The forums are retiring and are now closed for new topics and comments. The existing content will remain online and accessible through 2020 to provide everyone the opportunity to save any relevant information. In the spring of 2021, these Community forums will be taken offline.

Search for membrane in Topics

Swapping Rubber-Membrane for Microswitches?

Is it possible to convert a button from using a rubber contact to using a microswitch? The intent I have in mind is to take the buttons on a GBA and make them more like those on the SP/DSi/3DS, but the idea could be applied to any instance of squishy rubber-contacts.My best guess of how to go about this would be to trace the positive and negative leads into the switch on the circuitboard, then to somehow break that connection and reroute them into the microswitch by soldering wires to them. I need to go double-check the leads are available on the particular board I'm working with, and I wanted to test the general theory using a cheaper board like a TV remote.Any thoughts?

Question by Oi27    |  last reply

Can I use membrane keyboard by directly touching on the membrane layer?

What happens if I press on the membrane layer directly with my figners? Will I get shock or something funny happens? 

Question by xeonornexus    |  last reply

projecting images onto fabric or membrane

I Have a BIG project that I need help on! I have to fill a pavilion with images and other information on the Moon. I have to have this done for a festival and I have less than a month. I want to project images of the moon either static or moving onto loose hanging fabric around the pavilion. I saw a remarkable Cirque de Soleil traveling venue (see photo below) where they projected images on to translucent fabric which allowed the performers behind the projected images to appear to interact with them. This interaction is not necessary for my use but it was fascinating. (I have no idea how they accomplished this or how much that equipment costs) I will be most grateful for any and all suggestions that can help me with this project! Blessings to you all!

Topic by addinar    |  last reply

Dude plans to jump from a plane and land on his belly. Really.

Jeb Corliss has leaped from buildings and other places in a single bound. Now, he plans to do it without the aid of a parachute.Corliss, who is a base jumper, has made jumps in 16 countries and five contents, more than 1,000 in all, from the likes of the Eiffel Tower and Golden Gate Bridge.His latest venture is trying to jump from a helicopter and land without using a parachute.Corliss says he’ll wear a wing suit, which makes him look like a flying squirrel. He plans to landing on a specially designed runway he designed. It will cost up to $2 million. Once he gets the funding for his project, he says it could take up to four months to actually pull off.He added, “A wing suit, basically, is fabric that goes between your arms and between your legs and it changes the shape of your body. So you become, in essence, a flying squirrel.'He explains that he plans to land on his belly, suggesting, "œImagine an aircraft. Aircraft don't land on their tails, they land on their bellies. That's exactly what I'm gonna become. I'm gonna become an aircraft. I'm gonna be landing on my belly.Why in the world would Corliss try this?"œI wouldn't say I'm doing this because I'm a thrill-seeker. I'm a person who has dreams and my life is based on making those dreams come true. And that's what I focus on."

Topic by fungus amungus  

Could you design a pvc woodwind instrument in tune with keys using a membrane reed? Answered

Pvc membrane pipe, tuned with in the key of either C or Bb

Question by bwells2    |  last reply

Where can I buy transparent touch switches? Answered

Basically I need a thin, transparent, pressure switch which can be glued, or otherwise bound to a glass surface, and determine when something is resting on it. It only needs to be an electrical switch, and does not have to report the coordinates of the contact. Any help is greatly appreciated!

Question by FutbolFan    |  last reply

Roof deck over synthetic membrane: water intrusion?

Oops, so I posted this in Outdoors before I found Home. Double posting is irritating but it's kind of relevant to both... I'm new to the forums here (long time reader, infrequent poster), if I just committed a major faux pas, gimme a heads up and I'll take one of these down! Anyway, so the back door of my 3rd floor apartment opens on to what amounts to a raised back yard; the only problem is that this "back yard" is the roof of a 2 story addition to the brownstone I live in, and I'd rather not put my foot through a very expensive roof. I've been looking into decking, and right now my plan is a contact-only solid frame all the way around the perimeter of the roof, with a lip extending over the edge of the roof (to supply stability without puncturing the membrane) connecting to the actual frame of the deck which would of course be placed over the top of the brick walls of the building. From there I was going to face the deck with synthetics, probably with struts placed along the horizontal struts of the roof connected to both the upper deck and sub-deck cross bracing (depending on what materials I use/can afford and their relative strength). My hope is to find a way to make the deck in modular pieces that can be removed for when the roof inevitably needs to be resurfaced. So basically it would be large squares (or irregular shapes, whatever) that would sit on top of the struts/cross bracing with the help of a few screws and provide the deck surface. What I'm worried about is water intrusion at the contact points, such as around the edge of the roof and on top of the studs in the middle of the roof. I know synthetics are much more resistant to this type of failure than older materials, but are they impervious? Where do the pros put contacts so water doesn't leak into the floor below? Even if you minimalize it, the deck will have to come into contact with the roof at some point, or you've found some fancy new way of building I'd love to hear about. A few other thoughts are footprint: the building is an 1890 Richmond row house, could this be done with a small enough profile to increase the value of the property without damaging the "drive by" value? (I was picturing an iron railing to keep the project semi period, and this roof actually connects to the big hulking wooden fire escape, so it wouldn't be marring a virgin landscape) Also, do you think any building codes in the country would allow L bracing and big old bolts to hold the structure of the deck together instead of end-nailing the boards? It would make removal for roof work a lot easier. For the corners, would it be better to miter the ends at 45 and run a bolt through the two of them, end nail an L joint or use a thick metal l bracket and a few bolts to hold the joint together? That was kind of an intense post, I'm just looking to shoot the breeze a little bit with anyone who has any thoughts. Everybody always has their perfect way of doing things, on such a big, high pressure job (if this goes south I'd be poor AND homeless!) I want to really chew on the idea a little bit first. Thanks to anyone who actually read this far!

Topic by Macadaciouse    |  last reply

rewiring keyboard matrix?

I want to know if it is possible to rewire the traces that go to the numpad on a keyboard so that the numpad section can be cut out? I've seen some boards where this is done but no explanation was given of what's going on. The trace that is supposed to go to the numpad keys should be rerouted back somehow, I am guessing.

Question by phillyj    |  last reply

how to make a arrow only keyboard?

Im converting a laptop to a tablet pc but i want to be able to duel boot it with linux jolicloud because it looks like it should be a tablet os, and windows because of the things available for it. to do this i will need the arrow keys and the enter key but i dont want to have a whole keyboard just for those 5 keys. ive been looking around for the answer for a couple of weeks now and ive found out how keyboards work but not how to make one with arrows and the enter keys. thanks

Question by golfmaster03    |  last reply

How do i wire a custom made membrane keyboard/keypad to work on a pc?

I am looking into making a custom membrane keyboard, but i have not found a way to wire one to work with a computer to use it as a keypad...

Question by ClemensY290    |  last reply

What kind of plastic film is this?

Hi All, I've come across this art installation by Ann Veronica Janssens and would really like to find out what this semi reflective material is for a small project I'm working on. Does anyone have any idea what it may be and where would be a good place to source something like it? Thanks 

Topic by MadhavK16    |  last reply

IBM model M has 5 keys that do not work. How can I clean those contacts in the membranes?

The keyboard is in excellent shape otherwise.  Can I puncture the bottom metal shell in the locations in trouble and then inject contact cleaner?  Are there some other vent holes that might be used?  Could it be an electonic problem or circuit board plating in those areas?  The five keys affected are : g,  h,    apostophe ,   up arow,  and the number pad zero. Thanks

Question by rogets    |  last reply

What's the best design for a touch sensor embedded in ~4 mm layer of silicone for prosthesis (Hand)?

I need the sensor to activate a motor, on and off after being touched. Preferably, with no IC.

Question by julanm    |  last reply

Hi..I am interested in building a vacuum table of the sort used when attaching wood veneer to another type of wood Answered

I understand the priniciples, but don't know what to use for the membrane that lays over the work or how it would be sealed at the perimeter...

Question by aw1929    |  last reply

Printing a circuit on clear plastic?

Hi Guys Inside most modern keyboards, you find a rubber membrane that presses a sandwich of three layers of plastic, with the upper and lower parts having circuits on them that make the contact. Is it possible to 'print' this type of circuit at home on standard laser or inkjet printers?  I could use Amanda's method with bare conductive ink, but printing would be better. Any info appreciated ;)

Topic by wizer    |  last reply

How do I separate the laminate layers in an old bullet resistant window? There is no glass layer,

It is all plastics. I want to harvest the two inner 1/2 inch layers of Lexan for projects. The two outer layers appear to be 3/16ths UV resistant plexi. The center membrane is killing me. I have tried mild heat and brute strength.

Question by JimFlo    |  last reply

how to fire clay Answered

Hi i have been trying to make a clay membrane at home ( similar to kitchen tile ). i have used clay from art store and home depot without any success. after making a plate  of various ticknesses , i dry the plate for a few days but when i try to heat it it will breaks down , makes a popping sound and chips off. any suggestions ? thanks Michael

Question by pacbe11    |  last reply

Proposed Evaporative Air Conditioner

Have an idea for a Evaporative Cooler.  In most conventional coolers a fan pulls warm air through a panel that is constantly soaked in water, the water pulls the heat from the air.  Another form of this system is the simple "Mister Jets" that spray a fine mist into the air which pull the heat from the air dropping the temperature.  My idea is a combination of the two... See Image. The concept is simple... - Fan pulls warm air in and forces it into the body of the cooling unit. - A mister sprays a fine mist that combines with the air pulling the heat out. - To remove the fine air molecules a synthetic membrane (like pond filter material) is used to collect the vapor and allow the air to pass freely through. - The resulting water will make its way down the membrane and drip into the water basin below. - The pump will then recirculate the water back through the system. Seems like an easy enough system, the only problems I can see are... - Mildew - Leaks - Filter doesn't remove all the water So let me know if you guys think this will work.

Topic by scubaru    |  last reply

Can you see the strings? ("Yes")

You may have seen on the news that a Dutch chap claims to have flown under his own power from a standing start. Watch the video... I don't buy it - I think that... those wings beat too quickly to generate enough lift (compare to the beat-rate of much smaller swans, eagles and condors) the wing membranes don't show enough sign of being under load - they're too loose and flappy. the wings look the same on the down- and up-strokes the upstroke should push him down, because the membrane doesn't close up like a bat's wing, or let air through like a bird's wing. In fact, I reckon he's on strings. What do you think? UPDATE Thanks to those comments from The Usual Suspects - so it's a fake after all. I ought to point out, as well, that the BBC had been reporting this on their website as well, but the story has mysteriously disappeared in the last few minutes (I didn't provide the BBC link, since most non-UK readers are able to see video on their site).

Topic by Kiteman    |  last reply

Can two MIDI devices be on the same output?

I'm making a keytar and was planning on finding a keyboard with  the number of keys that I want and a MIDI output, but I'm thinking that if I do find a keyboard, it won't have the pitch-bend functionality. Could I have an Arduino read a membrane potentiometer and send that out the same MIDI port that the keyboard is sending the note data out of and have the pitch bend affect the note?

Question by mbudde    |  last reply

Replacing laptop key

Hi, I have what can only be described as a "no-name" laptop sitting in the bottom of a drawer. Among other things it has a missing "G" key. The problem is I have absolutely no clue how to replace the key - I'm not going to pay for a whole new keyboard and the key + "springy bit" is long since gone. The only branding I can find is "Clevo M300N". I was hoping to buy a broken laptop and cannibalise it (there are other hardware issues, but the keyboard is driving me nuts) Can anyone give me a shove in the right direction here? (Sorry for rambling) Edit: UPDATE - I found the key, all I need now is some kind of spring or membrane to fix it right up!

Topic by voltagex    |  last reply

Inventing on Vacation: Wounded Fish

This idea came to me after a day of fishing (I lost my best lure, but through the miracle of snorkeling, found it.) This seems like a simple idea, and I'm surprised it hasn't been invented yet. It is an improvement on the lures that supposedly look like a wounded fish.The idea is simple. A small, sealable "refill tube" connects to a hollow area inside the lure. This is the reservoir for fish blood. A thin membrane on one side of the lure allows the blood to seep out. You refill by filling an eyedropper with blood and inserting it into the refill tube. (I'm being brief right now because this is the third time I've typed this and I'm getting tired.)

Topic by Spl1nt3rC3ll    |  last reply

How to Make and Eat a Nine-Egg Breakfast

The secret is quail eggs. I found the quail eggs' membranes tougher than expected, and I had to pinch them to actually crack open the eggs. Quail eggs taste more "like eggs" than standard chicken eggs -- like the difference between a factory-farmed egg and an egg from my neighbor's chickens that eat grubs all day. You can hard boil them too. I started the eggs in cold water, heated it until boiling, let it boil for 1 minute, and then turned the heat off let the eggs sit in the hot water for 7 minutes. Finally, I quickly cooled them under cold water, and the shells were easy to peel.

Topic by ewilhelm    |  last reply

how could i bound polyurethane and silicone ?

Hi I'm trying to make a two part model in polyurethane resin with a thin silicone membrane connecting them so it can expend  and still be maintained by the silicone layer. The problem is that i need to pour the silicone into the model, so i can't make them stick together with some coating or glue. Instead of the silicone i thought about using polyurethane elastomer but it is usually not very elastic and does not age well when frequently teared neither. So i'm searching for a way to pour silicone into polyurethan resin and make it stick. Maybe eventually by putting some fiber on the resin surface while wet so it'll get trapped in the silicone layer while it will catalyze but i doubt it'll resist to the tear strengh for a long term use. Did any of you tried it or found a solution to that problem ?

Question by naomori    |  last reply

Convert a keypad into a large single switch?

Hi Guys, I need a simple switch with a large footprint to light up an LED bulb. I was thinking to use a 12 or 16 key membrane keypad or maybe an old keyboard keypad and rig it for this purpose but I've never used either of them for anything like this. My switch will be DC momentary switch with probably not more than 3.5V maybe 6V running through it off a battery. To make the entire keypad a sort of big single switch, would it be a simple matter of gathering all the positive wires from each of the keys together into one common wire and do the same with the negative wires or, maybe they have one ground wire? Then if any of the individual switches get pressed, will the switch activate ok?  If so, if two or more of the keys are pressed at the same time, will that cause a problem, like a short or over heating? Please let me know. Thank you so much!!! Bretina

Topic by Bretina    |  last reply

How to store hydrogen at low pressure?

What is the most practical and cost efficient way to make a 10m3 gas bag for the storage of hydrogen? I am planning to store pure Hydrogen (made from water electrolysis) in an outdoor area, a bit like the way biodigestor gas is stored in low cost, small scale installations. My concern is the high effusing nature of the gas through membrane material. My first thought was to use reinforced PVC like that used for truck tarpaulins but I can't find any info on effusing rates verses other materials. Ideally the gas would be able to remain in the bag for a maximum 2-3 weeks until needed. This is an experiment on the practical applications of locally produced hydrogen, so I hope to be able to follow up any advice by constructing the gas bag and reporting back with the project progress. Any thoughts and advice would be gratefully received! Thanks in advance, Nick

Question by Nick 73    |  last reply

SSTC using microwave oven inverter?

I recently obtained a microwave oven inverter and I've been doing a lot of research trying to figure out how to power it. The microwave I found came with schematics and a decoder for the button membrane so I am able to operate the main control board and the MICOM board outside of the unit (with slight modifications) but I have yet to test the inverter in fear of blowing it up. Currently my question is can I build a 555 PWM to cheat the CPU or bypass it completely? if not then I suppose I could use the microwaves original circuitry to do so but I'd like to build a nice solid state tesla coil with it if possible.  Instructables is being retarded and wont let me add notes to my pictures  image one - Main control board to the left, MICOM control board in the middle, Iverter on the right image two - Slight modifications to power the board outside of the microwave image three - Used decoding chart to operate main circuit without button assembly image four and five - Showing the output of the MICOM board going to the CPU on the inverter and settings of Oscope (channel A)

Question by Jimmy Proton    |  last reply

Actuated Matter Workshop / Zurich / July 25-29

APPLY NOW !!!! The Actuated Matter workshop explores the application of smart materials and their ability to transform space into responsive, adaptive environments. We will develop a speculative model for membrane structures that exhibit properties of sensitivity, resilience, and decay. By physically engaging with the behaviours of active materials, we experiment with the threshold between the electronic and mechanic, the analog and the digital. The workshop follows a do-it-yourself approach and will result in the development of sonic, luminous and moving modules that will populate and activate the environment. This workshop is part of a recent research initiative called “Emotive Environments” and emerges from a collaboration between ZHDK's Institute for Computer Music and Sound Technology (, the Interaction Design Institute (, ETH's Chair for Computer Aided Architectural Design ( and London based Loop.pH Design Research Studio ( Participants will work in small groups, each be led by someone with experience in the particular field of research. The workshop will be complemented by a final presentation and unveiling event, where you are also invited to come see the results, if you cannot attend the workshop. The workshop is free of charge. Application forms and more information can be found at: APPLICATION CLOSES JULY 13 

Topic by M.Kretzer    |  last reply

Circuit for a simplified DIY galvanometer?

I'm putting together a DIY performance lighting show set as a project and I'm currently working on the laser aspect of it. I've looked into the Galvanometers, which are used in laser shows and those units go anywhere from $60 to $200 a pop. So One thing is that I don't need to create any advanced imagery, I just need to vibrate a mirror at a fast enough rate in order to make a laser spread. My current solution is this: Basically a small motor pivoting a mirror along the axis. What I am wondering is, is there something more suited for this that isn't a motor or an expensive galvanometer. I've seen people attach a small speaker and supplying a pulse signal to make the speaker membrane rock back and forth. The volume of the sound would control the amplitude of the vibration but the downside is that it's actually audible, even more so than the motor. I remembered this episode of ElectroBoom, where a coil wound around a hollow cylinder would produce a magnetic field which would pull a metal object towards the center. Before I would go off trying to attach a metal rod to a spring and repeatedly turn the electric magnet on and off to simulator osculation. Perhaps people would know of something like that which already exists?

Question by MilesT9    |  last reply

RGB LED Bathroom shower light project problem. ?

I finished two bathroom reno's with the exception of the shower ceiling light. I started off by cutting 3 1/4: square 304 stainless steel plates and drilled out 4 holes in each for the rgb. Then assembled the rgb's into the housings and sealed them with hot glue. Then figured out the resistors based on 12 V which if memory serves me right they were 470 ohms and soldered them in parallel. Then I soldered the connectors and hot glued them so they wouldn't come in contact with each other. After installing the ceiling tiles I drilled 2 1/4" wide X 2½" deep holes through the kerdi membrane and sealed a plastic cover with foam insulation in the attic. Then I roughed in rgb cable from one hole to the other, with a home run to the controller. I tried doing a rough in trial run and it worked until one of the rgb�s burned out since they came in contact wth each other. I could actually hear it fizzle. Anyone have any suggestions on how I can make this work or are there retrofit rgb units that will fit the opening without breaking the bank? Each bathroom has 6 rough openings. That would make it 6 x 2 = 12. I'd like them to be rgb leds and be controlled via 12V adaptor and controller. If I need to start over again I have a budget of $150.00 if a another unit would work better. Thanks

Question by My Dream    |  last reply

Charging BoostCaps

I recently got a few of the 3000 farad 2.7 boost caps from electronic goldmine.  I have a quick question about charging them.  Applying a higher than rated voltage before the capacitor is charged all the way would be fine, right?  The voltage drop should cause the source voltage to approach 0, thusly below the 2.7 volt rating.  As an extreme example, lets say you simply hooked up a 9 volt battery to it.  Since the battery can only supply like 200mA, the voltage drops to nearly 0 as the capacitor appears to be a dead short.  The dielectric (or ion exchange or napheon membrane or whatever it is in a ultracap, lol) should be fine, correct? My main goal is to later hook up one or two of these for a regenerative brake system of something like a small gokart or bike or something.  Stopping at 30mph is like (assuming 200kg total mass) 20k joules, and each one can hold about 10k joules, and assuming a max efficiency of like 30 or 40% (I think itd be much lower, though), these capacitors could brake a gokart going fairly several times without having to be discharged inbetween cycled (but of course they would be).  For braking, could these essentially be hooked up directly (of course with pwm, and other things, but in essence:) to the motor with a little protection circuitry to prevent overcharging the capacitors?  Or would the higher voltage instantly puncture and destroy the boostcap?

Topic by guyfrom7up    |  last reply

Make supercapacitors from graphite in a DVD burner

The outline is that you can deposit graphite oxide (a cheap bulk material) onto a film of PET (the plastic used in Coke bottles), hit it with a commodity infra-red laser (such as the one in a $30 LightScribe DVD burner) and end up with a form of activated carbon material that can be used as the electrode in an electrolytic capacitor.  Add some aluminium foil, separator membrane and electrolyte and you've got cheap, robust energy storage.  The headline numbers are a few hundred milliFarads per cubic centimetre at a few volts, which works out to 1.36kWh per cubic metre of stacked capacitors.  It's still about 50 times less energy per volume than lead acid batteries, but you could store as much energy as your house will need overnight in the size of a garden shed or a set of bunk beds.  They charge/discharge in seconds and retain >95% capacity at 10,000 cycles so seem suitable for storage to even out intermittent energy generation from, for example, solar or wind power. I'm really thinking about cost here- unless I'm missing something fundamental it doesn't seem like producing these on a high volume roll-to-roll process would be excessively difficult, and the cycle life means the replacement time would be many years even in heavy usage.  Could you get sufficient kWh per dollar to make these a viable storage mechanism for home-scale renewables? There's a more informative article here.

Topic by PKM    |  last reply

Windbelt, Cheap Generator Alternative, Set to Power Third World

Working in Haiti, Shawn Frayne, a 28-year-old inventor based in Mountain View, Calif., saw the need for small-scale wind power to juice LED lamps and radios in the homes of the poor. Conventional wind turbines don't scale down well -- there's too much friction in the gearbox and other components. "With rotary power, there's nothing out there that generates under 50 watts," Frayne says. So he took a new tack, studying the way vibrations caused by the wind led to the collapse in 1940 of Washington's Tacoma Narrows Bridge (aka Galloping Gertie).Frayne's device, which he calls a Windbelt, is a taut membrane fitted with a pair of magnets that oscillate between metal coils. Prototypes have generated 40 milliwatts in 10-mph slivers of wind, making his device 10 to 30 times as efficient as the best microturbines. Frayne envisions the Windbelt costing a few dollars and replacing kerosene lamps in Haitian homes. "Kerosene is smoky and it's a fire hazard," says Peter Haas, founder of the Appropriate Infrastructure Development Group, which helps people in developing countries to get environmentally sound access to clean water, sanitation and energy. "If Shawn's innovation breaks, locals can fix it. If a solar panel breaks, the family is out a panel."'Frayne hopes to help fund third-world distribution of his Windbelt with revenue from first-world applications -- such as replacing the batteries used to power temperature and humidity sensors in buildings. "œThere's not a huge amount of innovation being done for people making $2 to $4 per day," Haas says. "Shawn's work is definitely needed.'

Topic by ewilhelm    |  last reply

Where can I find a screwdriver for an Etch-A-Sketch Animator?

I have an old Etch-A-Sketch Animator from 1986. The rubber membrane buttons barely work now. I would love to take this apart and clean out the buttons but the security screws in this are very weird - a funky kind of three bladed thing for which I have never been able to find a bit/driver. It's not Tri-Lobe, Tri-Wing or Tri-Groove. It's a standard pan top screw with three slots, separated in the center by a tiny "triangle". The slots come together much more closely than Tri-Groove. The ends of the slots closest to the center of the screw are more shallow than the edges closest to the diameter of the screw. A Tri-Groove might work, but I don't think the driver is going to clear the outer plastic housing. If anyone knows where I can find a bit to remove these, I'd appreciate the help! As far as advice on improvised removal techniques: Dremel techniques or any kind of "use a pair of dikes" technique won't work here because the screw is recessed by about 1.5cm in a channel that is maybe 1mm wider than the screw head. I'd like to avoid "Melt a pen" techniques to avoid damage to the casing and/or getting a pen permanently melted into the shaft. Besides, with the size of these screws (1/4 inch head?) and the age of the device, I doubt a Bic pen will have the torque necessary to pop the screws. (Keeping that under my belt as a last resort, though.) Links to a recommended Tri-Groove set with plenty of differently sized bits would be awesome as a second to last resort. There's so many and I'm a bit out of my element.

Question by inanis    |  last reply

Saul Griffith awarded a MacArthur grant!

Saul Griffith from Squid Labs, Howtoons, Instructables, and other cool companies has been awarded the MacArthur "genius" grant. He gets $500k because he's so genius-y and it couldn't be going to a better guy. Saul Griffith is an inventor whose innovations span industrial design, technology, and science education. Through a variety of endeavors at MIT and as a principal in Squid Labs, Griffith demonstrates his boundless energy for inventing across diverse disciplines in the global public interest. While still a graduate student at MIT, he designed a unique membrane-based molding system that can produce a variety of common lenses from a single pair of flexible molding surfaces. This prototype has the potential to change the economics of corrective lenses in rural and underserved communities around the world and continues to be a major focus of research and development energy at Squid Labs. At MIT, Griffith co-founded, a web community that has produced socially conscious engineering solutions, such as novel household water-treatment systems. is the forerunner of, a remarkable do-it-yourself website driven by user contributions. He is also a creative force behind HowToons, an animated educational resource designed to engage children in hands-on science and engineering projects. Through the spin-off company Potenco, Griffith initiated the project design for a hand-held human-powered generator, which has the potential significantly to improve access to electronic devices such as laptops and water purifiers throughout the world. Though still quite young, he holds several patents in optics, textiles, and nanotechnology. In these engineering ventures as well as others yet to be imagined, Griffith is a prodigy of invention in service of the world community. Saul Griffith received a B.MET.E. (1997) from the University of New South Wales in Sydney, Australia, an M.E. (2000) from the University of Sydney, and an M.S. (2001) and Ph.D. (2004) from the Massachusetts Institute of Technology. He is a co-founding partner of Squid Labs and serves as a technical advisor at Potenco in Alameda, California. full story

Topic by fungus amungus    |  last reply

using calcium chloride as humidity reducer closets /laundry rooms

I bought a product called "damp rid "in a hardware store that was used for removing moisture from hamper area,laundry rooms, to prevent mildew. i realized the pelted looked familiar and it was calcium chloride. i want to make my own as i have access to a big bag of calcium chloride. it looks like there is a piece of tyvek/ or other moisture passing membrane on one side of the top upper half, the other 3 sides of the bag look like a mylar  type bag.  The seams all seam to be sealed, except the top has a piece of plastic snapped-sea;ed over it, with a couple very small holes that go into the top half of the bag. the top plastic piece  also has a hanger  loop.. when i bought it the calcium chloride was in the top hang and the bottom half was empty. There looks like a plastic seam weld separating the calcium from the bottom half, and i noticed that are a couple 1/4 inch gaps in the seam. the calcium, chloride draws the moisture out of the air and turns it into water, which falls to the bottom half of the bag.pretty cool device, and seems i t would be able to make, if i can find a source for mylar or whatever this material is. i would also have to make the seams, not sure if glue would work, maybe make a clamp like device , rather than the welds, this way i could just empty the water and replace the calcium chloride, no reason to throw it out. anyone seen these devices, i noticed they have a www with the same name, they may have pictures.  Also looking for a source for mylar and tyvek.  I am not sure if the postal envelopes would work, i would also like to scrounge a sheet of tyvek to use as a ground-cloth or emergency shelter when out on my bicycle and the t storms hit. i haven't seen it except in big rolls, i guess i should keep a lookout for construction sites trash areas.otherwise i am not sure where  i could get a 10 ft piece. i will take the bag apart later to dissect the workings and see if i can measure the thickness of the  mylar

Topic by escapefromyonkers    |  last reply

Observing single photons (may be future Instructable)

In a thread on building a DIY Geiger counter, I mentioned that it's possible to do an experiment to see single photons directly with your eyes. This is a lab we did when I was an undergraduate, more than 20 years ago. I haven't done the setup myself since then, so I'm just going to describe it; if I have the opportunity run it again, then I'll make an I'ble.If someone else decides to tackle it, please feel free to write it up yourself!The human eye detects light via a family of proteins called opsins. Different forms of photopsins are sensitive to different wavebands, which is what gives us color vision. Rhodopsin is sensitive mainly to greenish-blue light, and provides us with monochromatic night vision. Rhodopsin works by changing its conformation when it absorbs a photon; that change of conformation allows ions to flow through the rod cell's membrane and generate a signal. The signal from each rod cell is processed through the retina and passed to the visual cortex, where a representation of the visual field is constructed.Human rhodopsin has a quantum efficiency of about 25% (there's a 25% chance a single photon will be absorbed and produce the rod-cell signal). By comparison, cat rhodopsin is more than 90% quantum efficient. 25% QE is sufficiently high to be observable -- a source of single photons can be seen by a dark-adpated person with normal vision.You'll need a steady source of well-collimated photons. A green laser pointer (~532 nm) will do nicely. But how many photons does it generate? A wavelength of 532 nm corresponds to 3.53×10-19 joules. So a small 1mW laser pointer puts out 2.8×1015 photons per second (watt = joule/s). How do you reduce that to one photon at a time? With filters. An ND3 neutral density filter reduces the output light by 10-3 compared to the input, so a stack of just five ND3's in front of this laster pointer would result in (on average) just 2.8 photons per second! A stack of four ND4's would give you 0.28 photons/s on average.If you don't have neutral density filters, you can make a decent approximation, by stacking sheets of black trash-bag plastic. To make this work you have to measure the attenuation yourself, so you'll need a photodetector, something which gives an output (voltage, resistance, current, whatever) proportional to the intensity of light.Once you have your single-photon source, you need to set it up in a completely dark room. If you have access to an old-style photographic darkroom, use it. Otherwise, use thick (3-5 mm) black felt and gaffer's tape to seal any windows and doorframes. Put the laser on a table or stand pointed at your face, with the stack of NDs (or trash bags) in front of it. If you're doing this by yourself, you may want to have a piece of tape set up to hold the pointer's button down. Otherwise, your lab partner will take care of it.Sit in the dark for 20 to 30 minutes. This will seem like forever, so you may want something to help you keep track of the time. A standard CD will be about half finished, or you can get through ten pop sons on your iPod, when your eyes become dark adapted.Turn on the laser. You'll see intermittent flashes all coming from nearly the same place in your visual field; if you turn your head, the location will move in the opposite direction. If you've used filters to get down to a few flashes per second, POV will make them easier to see. At less than one photon per second, you'll see them individually.

Topic by kelseymh    |  last reply


Hey there, I have been working on a recent project to build an Arduino Oscilloscope interfaced with a 4X4 keypad membrane with Nokia 5110 LCD display.I have successful individual code fragments/portions which 1)Generate waves interfaced with the keyboard  2)Display the same on the Nokia LCD 5110 i am using the Arduino Due and the 1st part of my code generates waves on DAC1 with the code as follows:- #include "Waveforms.h" #include #include //Set the desired duty cycle in percentage double dc,t,a,d; long d_milli,d_micro,a_milli,a_micro,m,n; int stage =0; int sample_delay1; LiquidCrystal lcd(A2, A3, A4, A5, A6, A7); float sample_delay; String num1,num2; int wave1; String wave_name; double duty_cycle,k; const byte ROWS = 4; //four rows const byte COLS = 4; //four columns //define the cymbols on the buttons of the keypads char hexaKeys[ROWS][COLS] = {   {'1','2','3','A'},   {'4','5','6','B'},   {'7','8','9','C'},   {'.','0','#','D'} }; byte rowPins[ROWS] = {23,25,27,29}; //connect to the row pinouts of the keypad byte colPins[COLS] = {31,33,35,37}; //connect to the column pinouts of the keypad int i = 0; int sample; //initialize an instance of class NewKeypad Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS); boolean in_setup = true; void setup() {   Serial.begin(9600);   analogWriteResolution(12);  // set the analog output resolution to 12 bit (4096 levels)   analogReadResolution(12);   lcd.begin(20,4);   char key = customKeypad.getKey();   lcd.setCursor(0, 0);   lcd.print("choose wave: ");   lcd.setCursor(0, 1);   lcd.print("A=Sine");   lcd.setCursor(8, 1);   lcd.print("B=Triangular");   lcd.setCursor(0, 2);   lcd.print("C=Sawtooth");   lcd.setCursor(11, 2);   lcd.print("D=Square");   while( true)   {         char key = customKeypad.getKey();         if(stage == 0)         {               Serial.println("in stage 0");               if(key == 'A' )               {                 wave1 = 0;                 lcd.clear();                 lcd.setCursor(0,0);                 lcd.print(" Sine?      ");                 wave_name ="Sinusoidal";                 Serial.println(wave_name);               }               else if(key == 'B')               {                 wave1 = 1;                 lcd.clear();                 lcd.setCursor(0,0);                 lcd.print("Triangular?");                 wave_name ="Triangular";                 Serial.println(wave_name);               }               else if(key == 'C')               {                 wave1 = 2;                 lcd.clear();                 lcd.setCursor(0,0);                 lcd.print("Sawtooth?  ");                 wave_name ="Sawtooth";                 Serial.println(wave_name);               }               else if(key == 'D')               {                 wave1 = 3;                 lcd.clear();                 lcd.setCursor(0,0);                 lcd.print("Square?    ");                 wave_name ="Square";                 Serial.println(wave_name);                               }               else if(key == '#')               {                 stage++;                 //lcd.clear();                 lcd.setCursor(0,1);                 lcd.print("Frequency=");                 Serial.println("Frequency=");               }         }        else if(stage == 1)         {               if(key != NO_KEY &&(key=='1'||key=='2'||key=='3'||key=='4'||key=='5'||key=='6'||key=='7'||key=='8'||key=='9'||key=='0'))               {                 num1 = num1 + key;                 //int numLength = num1.length();                 //to adjust one whitespace for operator                 lcd.setCursor(10,1);                 lcd.print(num1);               }                             else if(key == '#')               {                     k = num1.toInt();                     Serial.print(k);                                                                                        int sample_delay_int = 1000000/(k*120);                           float sample_delay_float = 1000000/(k*120);                           float difference= sample_delay_float-sample_delay_int;                           sample_delay1 = sample_delay_int - 6;                           if(difference > 0.5)                           {                             sample_delay1++;                           }                                                                               Serial.println(sample_delay1);                           lcd.clear();                           lcd.print(wave_name);                           lcd.setCursor(0,1);                           lcd.print("Frequency=");                           lcd.print(num1);                           lcd.print(" Hz");                                         break;                                       }                   }                                                 }       } void loop()   {   analogWrite(DAC1, waveformsTable[wave1][i] );    i++;   if(i == maxSamplesNum)  // Reset the counter to repeat the wave     i = 0;   else delayMicroseconds(sample_delay1);                   } Next, I input these waves from DAC1 into analog input A0 to display on the LCD with code as below:- #include #include #include #define DISPLAY_WIDTH 84 #define DISPLAY_HEIGHT 48 #define ARDUINO_PRECISION 1023.0 Adafruit_PCD8544 display = Adafruit_PCD8544(8,9,10,12,11); //Analog Pins int channelAI = A0;      // probe #define DELAY_POTENTIMETER //disabled it I don't have it connected #ifdef DELAY_POTENTIMETER int delayAI = A1;       // delay potentiometer #endif float delayVariable = 0; float scale = 0; int xCounter = 0; int yPosition = 0; int readings[DISPLAY_WIDTH+1]; int counter = 0; unsigned long drawtime = 0; unsigned long lastdraw = 0; int frames = 0; void setup(void) {   display.begin();   display.setContrast(30);// you might have a slightly different display so it might not be the optimal value for you   display.clearDisplay(); } void loop() {    #ifdef DELAY_POTENTIMETER   delayVariable = analogRead(delayAI);   delayVariable = (delayVariable/100);   #endif   scale = (float)(DISPLAY_HEIGHT-1)/ARDUINO_PRECISION;     //record readings   for(xCounter = 0; xCounter <= DISPLAY_WIDTH; xCounter++)   {                                     yPosition = analogRead(channelAI);     readings[xCounter] = (yPosition*scale);     #ifdef DELAY_POTENTIMETER     delay (delayVariable);     #endif   }     display.clearDisplay();   //Draw Voltage Ref Lines   display.drawLine( 10, 0, 10, DISPLAY_HEIGHT-1, BLACK);   display.drawLine( 5, (DISPLAY_HEIGHT-1)-(.2 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.2 *ARDUINO_PRECISION * scale), BLACK);   display.drawLine( 0, (DISPLAY_HEIGHT-1)-(.4 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.4 *ARDUINO_PRECISION * scale), BLACK);   display.drawLine( 5, (DISPLAY_HEIGHT-1)-(.6 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.6 *ARDUINO_PRECISION * scale), BLACK);   display.drawLine( 0, (DISPLAY_HEIGHT-1)-(.8 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.8 *ARDUINO_PRECISION * scale), BLACK);   //display.drawLine( 5, (DISPLAY_HEIGHT-1)-(.84 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.84 *ARDUINO_PRECISION * scale), BLACK);     //Draw Voltage Ref Numbers   display.setCursor(0,((DISPLAY_HEIGHT-1)-(.2 *ARDUINO_PRECISION * scale))-3);   display.print((int)(5.0*0.2));   display.setCursor(0,((DISPLAY_HEIGHT-1)-(.4 *ARDUINO_PRECISION * scale))-3);   display.print((int)(5.0*0.4));   display.setCursor(0,((DISPLAY_HEIGHT-1)-(.6 *ARDUINO_PRECISION * scale))-3);   display.print((int)(5.0*0.6));   display.setCursor(0,((DISPLAY_HEIGHT-1)-(.8 *ARDUINO_PRECISION * scale))-3);   display.print((int)(5.0*0.8));     for(xCounter = 0; xCounter <= DISPLAY_WIDTH; xCounter++)   {     display.drawPixel(xCounter, (DISPLAY_HEIGHT-1)-readings[xCounter], BLACK);     if(xCounter>1){       display.drawLine(xCounter-1, (DISPLAY_HEIGHT-1)-readings[xCounter-1], xCounter, (DISPLAY_HEIGHT-1)-readings[xCounter], BLACK);     }   }   //Draw FPS   display.setCursor((DISPLAY_WIDTH-1)-11,0);   display.print(frames);     //Draw Voltage   display.setCursor(((DISPLAY_WIDTH-1)/2),0);   display.print(analogRead(channelAI)/ARDUINO_PRECISION*5.0);     display.display();     //Calculate FPS   drawtime = micros();   frames=1000000/*a second*//(drawtime-lastdraw);   lastdraw = drawtime; } Now the problem arises when i try doing the 2 things on d same arduino due board. I got perfect results when i used arduino due and arduino uno simultaneously but have not been able to generate waves on the LCD using the same board. Is it possible to do the same. Can some1 help me incorporate the 2 programs into 1..Thanxx

Question by ranjana_1    |  last reply

UV filtration in your fish tank or small fish pond

Year after year the topic "I have a fish tank" seems to go more out of control. What was once a hobby just to have some fish can now be a design feature both in your home and inside the tank. Realistic looking lasdscapes, optical illusions that make you think the tank is much bigger and the list goes on. But one thing that now always pops up is the must have thing of UV filtration. Or to be precise: UV-C sterilisation! Now, if we trust Wiki and our big water suppliers then UV-C will literally kill anything alive that comes into contact with. So of course it would be a good thing to have for your tank - or not? UV-C is very dangerous for your eyesight and quite harmful for your skin! Looking into a proper UV-C lamp without protection means you can go blind! Even good sunglasses might not have enough protection in the UV-C range, so only use them for additional protection but never without and glass between you and the lamp! Don't be a fool! Treat UV-C seriously! You would not look into the full sun with your sunglasses and would not expose your eyes or skin to a powerful laser, UV-C is to be treated the same way! Let's start by using some boring text to explain the concept a little bit. On a large scale special and quite powerful systems are used to treat our drinking or pool water. Here special UV-C lights with a wavelenghts of 260nm or below are used to shine through the water passing by. There are two key factors here. a) the wavelenght b) the water flow rate and the corresponding time the water is in contact with the UV light To ensure all bacteria, viruses, algae and other harmful organics are dead the water must circulate for long enough so even the last water molecule had a few seconds of exposure. All this only works good with "crystal clear" water for obvious reasons as otherwise the UV has to be even more powerful to pass through. Single cell organisms literally crack into pieces similar to being exposed to gamma rays, more complex cells like algae have their cell membranes damages and the DNA suffers as well causing reproduction loss and early death. Even some chemicals break down, most importantly here chlorine based substances. Differences within the UV-C range! If you bothered to check Wiki about the topic of UV-C you will already know that only certain wavelengths within this spectrum will actuall be powerful enough to do what we want it to do. And here is the first problem for us hobby users. Most cheaply advertised "sterlisation lamps" you find in places like Ebay are actually totally useless. Stating to be selling a UV-C light to sterilze your water in such a case is still not considered to be fraud though. Simply because it still does what it supposed to do, just very slow and with very little effect. Only the so called "short wave" UV-C range is powerful enough! To avoid loosing business during the times of the biggest hype in 20 years no seller will actuall state the available wavelengths. That means without this info anywhere you can be certain the advertised lamp is of little to no use. Even those advertised to be short wave UV-C might not be the real deal. However, if a decent manufacturer is behind the actual lamp used it is possible to check the datasheet for these performance figures - but again most cheap systems come with no-name lamps inside. Check the prices for a reputable UV-C light with the same lamp fitting, e.g. G23 and you will see it might cost more than your entire system. Ok, you have a poper short wave UV-C lamp or consider getting a canister filter with one in it.... Never, ever test your lamp without proper protection!!!!! UV-C will damage your eye within seconds! If you system or lamp does not provide a viewing port or shine through area then you have to place a piece of glass between you and the light! UV-C won't be able to penetrate normal window glass but will pass through quartz glass. Place the lamp in a box and cover with the glass. How make proper use of UV-C sterilisation... The replacement lights are quite expensive, so let's see how to get the most out of them. As said before exposure is the key factor so the flow rate of the UV system must match tank size and flow rate of your filter system. Canister filters with a build in lamp should be designed to match but I will tell you later what to look for ;) Most of us will prefer to have a in-line system if there is already a good canister filter at work, so I will focus on those and rop in solutions. If you compare in-line system you might notice that some quite small and low power units claim to allow for the same flow rates as for example 40W units. Some are fraud and just want to sell while others use simple physics to make the claim true. A good system will utilise an auger like "ramp" that forces the water to circulate around the tube many times - causing up to ten times longer exposure rates. Others create this sprial effect more like a vortex with some diverters and modified inlets. The later seems to be less efficient though with low power lamps. An in-line system should be on the outlet side of your canister filter so the best quality water will pass through it. A drop in solution should be used alone and without the existing normal filter pump you might have in there. Ok, got it, but how do I actually use it now? Despite common thinking a UV-C system should not run 24/7 like your normal filter. You really only need it to solve problems you should not have in a healthy tank! It is not a magical solution to make your underlaying problems go away ;) Let's start with the most common reason someone buys a UV-C system: An algae or bacterial outbreak causing greenish or milky water. If that developed slowly over a period of weeks then you would be better off to do a good clean of the tank and filter plus a decent water exchange. A few drops of meds will do the rest. And if you constantly get algae growing on your glass, ornaments and plants then your nutrient levels and water quality is not right anyway and needs a good check. But of course there is also the problem of light - too much for too long and unwanted gree appears everywhere. If in doubt reduce the light power, shade out natural light or reduce the on time for your lights. Having said that we now face the problem of a sudden outbreak after introducing new fish or plants. If you don't have a quarantaine tank chances are that sooner or later you get unwanted or even harmful guest into your tank. Here the UV-C will be beneficial, which is why a canister filter with build in light should have a seperate switch or power supply for the light. After an outbreak or while introducing new life into your tank the UV-C will remove a lot of the things that we don't want to bring along. For new life I leave the light on non stop for a week, that is for a small 4ft tank with 200 liters. To control an outbreak it depends on how bad it is. I assume here you can still see the back of your tank  but that the water either appears greenish or slightly milky from bacteria. As a personal thing I prefer to to remove and clean my filter material before treating a severe outbreak. Once done I fill the filter with a mix of activate carbon material and fine filter wool. Reason for this quite simple: The outbreak causing stuff is already in your filter material and will be a constant source of re-infection. And since breaking down all this bad stuff causes even more bad stuff to be produced as biological waste we want to discard it properly once done. Using just fine filter wool and activated carbon also reduces the flow rate bit if compacted ;) Now we can turn on the light and pump and forget about it for a while. It is not recommended to run UV lights on a timer as you want them on all time to prevent short lifespan and have ongoing treatment of the water. Good idea to take a picture at the same of a day from now on to compare and check results. After 3 days the water should definately be clearer, if not then either your filter material is packed too losse or the lamp is no good. Once the water appears to be clear do a readin test - take a newspaper behind the tank and check if the text is clear - blurry means the water is still not clean. You will reach a point where the water quality will not further improve as much as in the days before. This is the time where you discard or clean out to dry your filter material and put the original stuff back in. The activated carbon should be discarded of course. You cleaned filter material will now need a certain time to grow enough good bacteria to go back to the old performance. During this time you should still leave the light on. In most cases with enough fish and plants in the tank a week should be sufficient. After that you can leave the light off and keep the tank fit and healthy. Special case: Algae everywhere! Especially after getting a new plant you can end up with quite pesty algae growth. Be it these long ghost hair types or in a bad case the black stuff growing on plants, ornaments and the glass. I have even seen tanks with algae covering the entire bottom of the tank causing the gravel to look like carpet. Here I can only advise to set up a quarantaine tank for your fish. Then remove all infested material for manual removal and cleaning. Infested plants should be cut clean and what can be boiled should be boiled in water for a few minutes. Now start scrubbing in the tank with ongoing water replacements. I prefer to let everything settle over night without any bubbler or pump running. This way I can suck up a lot of sediment the next day. If you can remove all plants and fish you can now use hydrogen peroxide and add it to your tank water. But this is only feasable for small desktop tanks. Before using the UV as above to cure an outbreak you should consider all water one last time. Allow at least 2 weeks with ongoing water checks before adding plants back in and another week before placing your fish back in the tank. The week before adding fish should be used to monitor the plats for any signs of algae you might have missed - if you find any remove it! A week after the fish is back in you can turn off the UV light. Underwater UV-C light!? In most online stores you will find quite cheap UV lights to be advertised as underwater or in tank use. Although it might sound tempting you should be well aware of the dangers of using them. The glass of your tank will block the harmfull UV rays but the water surface won't, so either don't ever look at it or use proper sunglasses with real UV protection. Apart from the dangers to you these lamps are not just cheap in price but also cheaply produced. That means there is no way of telling how much or how little UV-C is produced. If they are good then you still need to know in what type of tank setup you can use them. As plants can tolerate a bit of UV a placement as far away from the nearest plant should do, especially if you can place a bubble wall betwenn light and plants. The fish is another thing as some seem to be unaware of the danger in their tank. This means they can get too close to the light but I have not found any articles explaining how harmful UV-C is to fish or their eyesight. I guess once your fish starts to bounce into everything you know... ;) My advise is to stay away from the idea of hanging a UV-C lamp in your tank, the risk for you and your tank is just not justified. If you need to go cheap then get two or thre of these lamps so you have spares. But use them externally ;) Meaning: Take a UV proof plastic container of small size and place the light in there. To be really safe tape the lid and all holes for the hoses with black tape. Place the container above the water level of your tank and if you only have an internal filter pump push a suitable sized hose into the outlet to feed into you canister. Check how high you pump can make it and place the outlet or overflow slightly below this level. When to change the light? If you made it all the way down here then you might already had the benefit of using light to "cure" your tank. Now we are faced with the high replacement cost for the lamp itself. Ususally only flouroscent tubes are used. It is always good to check after purchase what type of lamp and manufacturer (if there is one) was used. In some cases the system itself is like an inkjet printer: Just a cheap way to make you buy the consumables. Let's say you new in-line filter was priced at $100 to have a nice round number, some are cheaper some much more expensive. The lamp used might be an exotic type and not even be available easy, so before you buy your system check where you can get spares, not just the lamp of course. A replacement lamp can be as ceap as 20 bucks or cost even more than your system if you need to order it elsewhere. The quartz glass sleeve can break too meaning you then need a lamp and cylinder. Going with a reputable brand and paying a bit more certainly helps to get spares in the future. Let's just assume you either got your system in bulk due to the price of replacement lamps or can get them at a reasonable price. UV-C lamps are not like your normal flouroscent light tubes you have around or maybe even on top of your tank. Consider them like the tubes used in the now unhealthy tanning beds. After a certain amount of time they no longer produce enough of the short wave UV light that we need. As you can't see it and most of us won't have the means to specifically measure it we have to trust manufacturers recommendations. For most good brands the numbers are the same: 8000 hours max. Considering the costs it does make sense to keep written track of the usage. Not too hard since we won't use them like normal lights but instead have them on for a week or more without turning them off. I recommend to have a replacement at hand long before you need it. A lamp can fail premature, crack or simply burn out. The 8000 hours are based on 24 hour usage, so one day on, one day off. This could mean for us the lifetime can be slightly longer but I would not go over 9000 hours. As a rule of thumb: If the water does not show good signs of getting clear on day thre the lamp is due.

Topic by Downunder35m    |  last reply

Magnetmotor - really impossible or just supressed?

When someone starts talking about a so called magnetmotor than most people judge right away.Laws of physics, perpetuum mobile is impossible, magnets are static....We all know the limitations nature puts on us... That however did not stop quite a few people since the 1950's to build working magnet motors. Or, to be precise: To make the claim, show them and then somehow disappear. A few though seem to have survived and even claim to make good business. Securely closed machine, stellite tracking and 24/7 online monitoring. Either just a bad and long running hoax or a real attempt to keep a secret secret. Even the somewhat famous Yildiz motor showed off around the world only to disappear.Some like them, some don't. Either way all this sounds like the perfect conspirary theory LOL So lets take a look on what is fake and what might be real but missing some vital clues. You can find several good Youtube channels created by people trying to build a working magnet motor. Some of them have no problems to admit failure and still keep trying and updating their projects. Did long enough and you see two outcomes. The first is giving up or "realising" that it will never work. The second often seems like a user is getting some relly good results and is really close to keep the magnetmotor running. Both disappear without and updates or traces. Now of course this is just confirmation that it will never work, but then again: What if it did already quite a few times? Even Tesla had patents for a magnetmotor and so far none of his patents were a hoax. Although none of his patents allow to actually build a working devices without some additional info and knowledge. And that is the key that I am trying to get: The lost knowledge.How can a magnetmotor never work? That one is quite simple from the start. If a linear model won't work no matter where you start then a rotary version will fail as well. And if a linear version works, it has to do so far at least 5 segments and with preferably increasing or at least constant speed. Having said that and assuming you know a little bit about magnetism: Ever wondered about shapes of magnets?? The common types are block, round like a bar and those disk like ones, some even with holes. A less well known version is the ring magnet. You can look them up as well as their corresponding magnetic field geometry - or what is assumed to be the right geometry. To give you a clue: All those floating spinning toys use a ring magnet in the base and onother one in the spinner. In the center is a dead zone for the magnetic field that is far lower than further out on the ring. And the strnger outer fields also reach further - giving the entire spinner a bowl like area to float on, the spinning just stabilises it like a gyroscope. A similar flat disk magnet wouldn't have this indentation in the field but rather a dome like sphere. The ring just kicks a dint into this sphere if you don't mind the simpification. Similar changes in the field structure happen when you combine two or more magnets. One example we all know is stacking identical smaller magnets. And often we are suprised how much stronger two thin disk magnets are compared to a single. Distance however sets a certain limit. And take those hook magnets... Just a small ring magnet in a metal pot with core. Remove the magnet and just by itself it is far weaker. Why? Quite simple.... The same way a transformer core directs the magnetic flow, the metal part of the hook magnet provides a shortcut for the magnetic field - and in return all is much stronger ;) Now you have some more clues, but still there are tons of options for failure... The most common is the sticking effect. No matter how well you planned and designed in most cases you linear or rotary prototype will stall sooner or later. Even if started manually at high speeds some seem to run very long but once they slow down and stop it is obvious they always stop where the magnetic field won't allow the binding effect to be overcome.Wouldn't dare to say that I have a working magnetmotor, but I might have some clues you want to try if you decide to give it a try yourself. So how COULD a magnetmotor actually work? Like in the Perendiv examples all over the web, you could aloow a moving responder to the rotor. Like a piston the responder will be lifted in areas it would otherwise limit or reduce the speed of the system. Well designed only a few mm would b required but it also means wasted energy to move the responder. Then there is the nice way of modifying fields by adding magnets in different angles and polarities. Lets say towards the end of your stages on the linear model it is hard to overcome the binding effect from the end of the previous stage. The perendiv model would now somehow change the distances. But you can also add magnets to lower the binding effect ;) Like a ring or hook magnet you can shape the field and offer a stronger repulsin field or a lower binding force. Last but certainly not least is the option of adding magnetic metals like iron or somehow weirder ones like bismuth. So, do we have any examples of something very common utilising any of this? We sure do :) Take a speaker apart and you end with the cage, the membrane, the actual work coil and the magnet. We don't need anything but the magnet so take a good and very close look. What in the audio world is called a shield to prevent the magnet from messing with things close by is exactly the same as on a hook magnet ;) Only difference is the tiny gap for the coil. The magnetic field is directed into two paths, one by the metal core, the other by the inner enclosure of the magnet or the magnet itself. The coil operates in the area of maximum flux.Last hints... If you take two identical and strong magnets with north or south facing up then it is quite hard to push them very close together. But check what happens if you try the same wen both soth poles (or both north poles) are placed on a magnetic surface - if in doubt your standard fridge door. Suddenly you can move much closer together with the same amout of force (not considering the added friction!). And similar story for opposing configurations. Where in free air or on a table the magnets would just jump together, on a metal plated you can move them much, much closer before this happens. Copper pipe and magnet fun :) Ideally you would have a straight copper pipe and a cylindrical magnet that has a loose fit in the pipe. Aluminium pipe work too or even a roll of aluminium foil if you have nothing else. A magnet in the pipe will travel very slow down the pipe, friction is not an issue here. So what is slowing it down? The magnet creates a field in the pipe and through that the pipe generates electicity. And funny enough this electricity creates an opposing magnetic field in the pipe - the magnet slows down. Even if you glue it onto a wooden stick it won't rush through it. Trying to push it by hand and you feel the created resistance. The faster you push, the harder it is to push! If you made it all the way down here with the reading then I have to assume you fit into one of three of my categories. a) You are a total sceptic and just read it for your amusement. If so, then please don't post a reply with usual negative feedback, instead see it as the same fun you had reading it ;) b) You are at least curious and like to play with magnets. In this case take the above as inspiration to explore more ways to have fun with your magnets! c) You are more or less frustated because you wasted a lot of time and some money to build a magnet motor that just won't work. A and B might go on and enjoy the fun, C however might want to read very attentive now ;) If you take some indicator sheet for magnetic fields, like these funny green ones, and play with moving magnets then you see a very interesting effect on the "screen". The otherwise static field lines change chape and sometimes even seem to disappear or shrink. With a small rotor assembly it almost looks like flashes when the magnets move past each other. This effect is often totally neglected and to be honest I overlooked it for a long time as well. Being able to see how the magnetic field changes gives the thing an whole new dimension so to speak. Creating a magnet with a complex shape is difficult to say the least. Only ferrite or ceramic ones can be used and you would cut of machine them according to your desired shape and with regards to the orginal center of the magnetic field. So most people revert to the classic way of shaping by adding magnets of various types, sizes and amounts. Modern neodymium magnets make this trial and error process easier as there are many sizes and strengths available. Add a detector shield of suitable size and you have hours of fun time ahead of you. But doing so in any rotary assembly is next to impossible. So what did Yildiz differently and what was missed so many times? Yildiz took it a step further and not only provided "shunts" to create very strong magnetic field from the generated electricity but also a second rotor. Since we all start small lets focus on the basics first. Remember the hook magnet and speaker or the copper pipe? Some examples for shape shifting your otherwise static magnetic fields: 1. A magnetic metal "connection" from one (low in the armature) pole to an opposing (high in the amature) pole with cause the field from the "high" pole to "bend" towards the connected magnet. 2. A magnet with an orientation of 90° to the last magnet is the sequence will severely influence the field of this last magnet! This goes for either orientations! 3. Adding a non-magnetic "shield" around a magnet, like a piece of copper pipe, will not affect the static field of the magnet. However it will severely alter the field of the enclosed magnet when another magnet passes it! It will also affect the overal field during the passing as the moving magnet will also induce a field in the copper by affecting the field of the enclosed magnet! Thickness and lenght of the shield influence the strength of these effects. 4. In a simple perendiv motor design the bar that creates the attraction for the spinning part is a magnet too. Either a long bar type or two small ones with an iron or nickel rod between them. There is no need for a piston or something that drives the bar up or out of the way ;) Just use the right magnet at the right spot on your rotor to repell the bar ;) Mount the ar with suitable springs and you suddenly can have multiple stages on your rotor instead of just the usual one! Don't forget the moving magnet on the opposing side of the segment in question though as otherwise you still will get stuck. (Hint: You can place a small but powerful magnet in the center of the opposing bar ;) Just make sure you limit the springs movement so the bar won't be pulled closer)Ok, hold on now! Does a magnet motor actually work or not? I can only give hints and say the laws of physics as we know them apply to magnetmotors the same way as everything else. Unlimeted motion without supplying energy is not possible. Limited motion with adding or using energy however is still possible and real. The same is true for being able to machine, 3D print or otherwise manufacture at very tight tolerence and accuracy levels. This includes bearings or bearing systems with very little friction losses. Just check these floting and rotating magnet toys that look like a spindle. Only a tiny needle like pin makes contact with a glass surface - next to no friction loss. A proper and supposedly working magnet motor should provide more energy than what it uses - one way or the other. No law of physics lets us get around the fact that such a motor could only keep spinning if the produced power or motion energy is at least the same as what is required to make it move. Magnets lose their strenght over time, they are like a very slowly depleting battery. So, isn't it funny that all magnet motors so far that claimed to work also had the requirement to replace the magnets once the things fails to work or start? And if you leave a very strong neodymium magnet shielded from outside fields or magnetic stuff than your grandkids will still find a quite strong magnet. Do a little performance test with your new magnets, like how much force is required is required to lift them off a steel plate. Make the same test with the magnets once you played around extensively with them in your motor. Now take a spare magnet that was never used from the orginal batch and compare both against each other ;) If the motor would not use energy then why are the magnets depleted to a certain degree, realted to runtime and usage time? Wait a minute! Does that now mean it actually works? Lets just say energy is certainly used. We only know similar effects from electromagnetic systems. But did anyone ever really check how much actual energy is in magnetic field generated by a non electric magnet? Get a good sized N52 neodymium magnet and check how much force is required to pull it off a steel surface. Now try to get the smallest sized electromagnet capable of that force and check how much energy it consumes at the level that equals the pulling force of the N52 magnet ;) Makes no sense to even try to compare these you will say now. I just say energy is energy and we were formed to only think in certain ways and don't even try silly things like this ;) To keep the fun up let us imagine we would actually have a similar energy available than what our electro magnet would require. In reality more because we wouldn't have electrical or flux related losses in the metal around the coil. Or is the imagined reality, no clue ;) If true it would mean even a motor with very bad efficiency would be able to create huge amounts of torque. Well, torque is basically acceleration. Which would mean our motor would not just be happy to spin, it would speed up until the bearing fail or the thing is ripped apart. Imagine a dental drill of that size and weight suddenly falling apart at full speed... Every example of motors claimed to be working, that are not fakes, seem to be happy no matter what the load is. It the thing turns a generator than it would have to slow down a bit with the increased load but they don't. With no limited factors otherwise this makes them a fake. Even a perfect motor would have to react to load changes.... Don't we agree that the stronger the magnetic force or field in a conductor the stronger the resulting magnetic and opposing field of the conductor? We use the difference to either drive a motor or take out electricity... But if you take the "open" shielding of a magnet in a changing field than the influence of the shield on the overall field gets stronger with stronger field changes. And properly desinged and orientated they would actually double as a natural limiter for the rotation speed. Once the electrical energy in the shield becomes too strong it will be able to cancel out the field of the enclosed magnet...If we assume a magnet motor is really possible and works with the intended output to keep it spinning or even take energy out: Then what would be possible downfalls that stop this thing happening in everyones garage? We can explore the stars but so far no one bothered to invent anything to visualise magnetic field in a 3 dimensional way other than by simulation. No realtime and true observation like this. The few working technologies that exist rely on sensors, interpretaion and filling in gaps. But imagine something like a detector shield as cloud! And then even better with selctive spacing to get a realtime view of where exactly the field lines go. All we can do is forget our teaching and try it out anyway ;) If by some mistake a magnet motor would really work right away, then chances are high the inventor would wonder why that thing takes off like mad and how to stop it. Unless well prepared it would certainly end in the destrution of the motor. But the inventor would know what to look for in the next prototype. The logical conclusion would be to the couple the energy taken to the speed while physically limittin the free load speed. The other one would be the design the electrical generator around the and within the motor. To even get close to this point you would have to spend endless days and nights working on finding a solution. The closer you get the more disappointment when the final model still fails to keep spinning for more than a few hours. Most people will then accept defeat and move on... Still not saying it actually works but if you made it to this point in time where it could be easier to move on and do other things:Ever wondered what would happen if you "shield" a magnet with a coil? Of course nothing would happen as we know. But try this in some fixed assembly that allows you move another magnet through the field of the shielded one. Perferably witha force gauge or some option to read out the energy required to move it through the various stages of the field. See what happens if you short the coil or add a resistor to it ;) Now if this coild is able to produce electricity then the more we use the more the effects on the required force would change. What do you think would happen if you combine common coil relations of electric motors to a "coil shielded" magnet motor? Right, all these coils would interact with the magnetic fields of the coils they are connected to... And through that with the overall field surrounding the enclosed magnet..... I leave up to you to imagine how these interacting coils could provide "resistance" or "acceleration"/"surplus electricity"...Like they say: You can only find out if you try ;) To keep up the positive thinking: A permanent magnet just sticks to any magnetic surface and does so with the same force. But the real energy loss in terms of getting weaker can almost be neglected. Any electromagnet capable of the same holding force woul require ongoing energy supplies to keep it up. It is using energy the same way the permanent magnet does! The difference is the permanent magnet is not seen as anything that would provide us with energy.... And if it can't provide energy other than passing through coils then why the heck does it keep sticking to the fridge year after year? It does require energy to keep this weight up doesn't it, even if you add a thin teflon disk and oil to reduce friction? ;) No magic, no "free energy" bogus, just plain physics viewed from a slightly different angle than what we learn in school ;) Have a good laugh and a good beer, then read it again and just consider some of the things here that are not mentioned in any literature about magnetism that we commonly use. Now I got you thinking, didn't I ? ;)

Topic by Downunder35m    |  last reply

Looking for a cheap compressor with a high pressure rating or for airbrush use?

Today a friend of mine asked me if I know a way to reduce the noise level of his compressor in the work shed. With the current heat he prefers to work in the evening and nights, which does not make his neighbours too happy. His main use for several airbrush guns and sometimes for mormal airtools or the big spray gun for an undercoat or similar. So his main concern is oil in the airline and the actual flow rate is of second concern as he has an old 25kg propane cyclinder as an additional air tank. For relative low air volumes I would suggest an old fridge compressor. With a thicker pipe at the outlet that is filled with stainless steel wool most of the oil stays in the compressor. That is if this pipe is a) long enough b) upright c) of sufficient diameter so there is enough for the oil to avoid it being pushed up A second, standard oil seperator will be enough for the oil level required for airbrush stuff - and most other things too. If there is no pressure regulator on the airbrush system it is best to add a small air tank and shut off valve for it. In our case however a fridge compressor would be just enough to keep the bigger airbrush gun running but not to fill the tank at the same time. Not to mention the problem of fluctuating pressure levels. Since we already had a tank and pressure shut off connected to the loud compressor it was only a matter of finding something that keeps the neighbours happy. The first thing we did was to check how often the compressor comes on and how long it runs till the tank is back to pressure. With that and the stated air volume on the compressor we guesstimated that something a bit bigger than the compressor of a window airconditioner should be sufficient. The search begins.... If you don't know what to look for I give you a few hints: Older airconditioners often run on R22 or R12 - both use quite high system pressures which is a bonus, but more on that later. As a rule of thumb for these compressors you cans say: the bigger the higher the flow rate. At the local wreckers and scrap yards we found a few units but noticed the bigger ones often used three phases and not just one :( So we opted for the R22 compressor of a 4.5kW unit. Keep in mind the 4.5kW is for the entire system, so the quite massive fans can be removed from the sum. Usually the compressor alone is the 2.5 - 3kW range. Ok, we found the big thing but how does this help us? First things first ;) The oil was removed as the housing stating the original oil amount. This allowed us to use an oil rated for air use that has little to no water absorption qualities - you don't want water in your compressor. With the usual heat the water should be no problem anyway. Next was a pressure test to make sure the thing actually still works, so we added some plumping in the form of standard connectors to the inlet and outlet. We got well above 200PSI and abondoned the test at this stage as it was more than enough already. The air volume seemd to be well more than expected too so let'S move to the next stage. A fridge or aircon compressor always needs to have a certain amount of oil in it as it will otherwise seize and overheat quickly. But they are also designed so that the oil mixes with the refrigerant to cool all moving parts. So the biggest hurdle is to make sure the oil stays where it should stay and won't enter or get lost in the tank. Only real option for this to use something to catch the oil that is capable of releasing it into the compressor once it shuts off. Now there are several options for this so I start with the most basic: A "catch can" will get most of the oil, especially if filled with stainless steel wool or similar. Downside is that you have to find a way to get it back into the compressor. A step better is a thicker pipe filled with stainless steel wool to catch the oil. If placed upright and the outgoing pipe can be bend a bit upwards you have a good chance that most of the oil will sweep through the valves and get back down into the compressor housing. But only too often the cheap or even free compressor is better than expected and the oil won't get back into the housing as the vlaves are just too good. The last and IMHO best option is a pressurised return system. Most compressors for bigger aircons have a seperate filling port or sealed off piece of pipe. In this case you can do a simple check to see if they are usable for our purposes. Open the port of pipe and use a simple bike bump or similar to get some pressure in it. With a dedicated oil filling port you are best off but they are hard to find. The air you pump in should come out of the high pressure side - you might need a little pressure to overcome the valves. If you hear any bubbling in the housing (use a pipe on your ear or a sensitive microphone) it means you are going through the oil inside the compressor - perfect! You might not hear any bubbling but the port or pipe is still usable. Get ready with your fingers and start the compressor. The fill pipe should be sucking air in, same for the service port if there is one. A dedicated oil port should not suck but instead force some oil up if you cover the high pressure outlet. I assume all is good and no oil is splashing out of the open pipe or port. Add a small amount of oil with a syringe or similar into the port/pipe. If you see an oil mist coming out of the high side it is bad news. Clean outlet air is good. To get the oil back from the catch pipe or can we have to add a hose or pipe with a needle valve. It needs to be adjusted so that there is only a very little airflow (or oil mist) coming out. This regulated outlet is now being connect to the port/pipe with a bit of suction that we found earlier. Now every time the compressor runs the collected oil is forced back into the compressor :) Please double check the port/pipe used is not directly connected to the intake port! The last thing you want is a puddle of oil going into the cylinder and damaging it! They are designed to move gas but not liquid! If in doubt use a hardened sttel nail or similar to create a small puncture in the top of the compressor housing if there is nothing else to use. Check first if the material sound very thick, if so it might help to drill with a 5 or 6mm drill first - only about 1mm to make sure you won't enter the housing and conimate it with metal shavings! Once you have a small puncture hole of about 2mm in diameter get some 2 component metal repair glue mix and add a suitable connection for the collecting pipe/can. If you feel up to it you can of course use a blow torch and solder the connection on. Now we have the compressor working with a oil return system that also gives up very little to no oil at all in our system. You might now think you are good to go but you should at least add a decent and fine filter to the air inlet ;) The compressor noise of a bigger system can still be an issue if thicker pipes are used that allow the noise to travel out. Keep in mind they usually run in a fully closed system.... As we only need to match the noise level of the compressor itself a solid steel can like an old fire extinguisher in the 1kg rage is a good way out. Fill it with filter wool and a fine filter pad after adding some hose connectors either end. You can misuse the trigger nozzle and keep it to seal the top if you braze a connector on it. If the intake here is about 5 times larger than the pipe connection to the compressor itself the air flow going into the thing is low enough for a cheap paper air filter can or box if you have a quite dusty enviroment to work with. The real trick is to have a hose or pipe on the inside of the fire extinguisher connected to the compressor pipe connection. A garden hose is great here as is reduces the noise quite good and is dirt cheap. Make a lot of about 2mm sized holes in this pipe and close the other end of it off. Now the compressor will suck it through the small holes and the soft garden hose reduces the noise, the surrounding padding brings it down to basically nothing. The special case of clean air for airbrush.... If you read this for the sole purpose of airbrush use then this chapter is just for you, all other might want to skip it. The two things you don't want to enter your gun is oil or water. Both are a common thing in normal compressors due to lubrication and pressure difference resulting in condensation of the humidity in the intake air. Oil free compressors of good quality can cost quite a few bucks and often require ongoing replacement of membranes or piston seals. A refrigeration compressor with the above modifications already provides clean enough air for most airbrush users if a proper tank is used to store enough of the compressed air. So you might just want to add a basic oil filter or very fine paper filter close to the regulator. For very detailed work with very sensitive paints you might want to build a filter box containing of several layers of oil absorbent paper. This stuff is often used in the industry to clean up minor oil spills and bind oil very well. A PVC pipe (pressure rated please) with 5-8 layers of filter screens should last about a lifetime before the filters need changing if the diameter is in the 10-15cm range. That leaves us with the dreaded problem of condensation and water contamination. Depending on the type of paint and gun used a small amount of water vapour is usually no problem. Solvent based paints usally show their disliking by unwanted drops or run offs caused by water droplets. Of course you just go and buy a professional dehumidifier and accept the ongoing replacement costs for the cartridges... But if you are in a climated that has above 30% humidity for most of the year than you will have to remove the water one way or the other. A big enough storage tank for the air that is upright usually helps to release any condensated water prior to usage. But if you use a homemade tank you might want to avoid this problem completely and forget about water in the system altogehter. Silaca gel is the answer here, specifically the indicating variety that changes color once "full". A spaghetti glas or similar should be big enough unless you are in a very humid climate - is so just use multiple in a row. The air intake side for the compressor has to go through the silica gel to be effictive. This mean we need two holes in the lid. One with a pipe or hose going all the way to the botom - that is the air intake side. The other right on the lid - this is the air outlet side which continues to the compressor intake. With the color change in the silica gel we can estimate how much usage we have left until we have to heat it up to remove the water. If this color change happens quite fast from the bottom to the top, let's say within three days or less than you really need to use more jars with silica gel in a row or a longer one - like using a long and clear acrylic pipe instead. Of course you can always just cut holes and "viewing glasses" along the length to a PVC pipe.... No matter how wet your climate is you want to get at least 100 hours of compressor run time before you need to recharge the silica gel. This brings us to the recharging.... Once the color changes and you only have about one quarter left to the top you want to get the water out of the gel and re-use it. To do this you simply heat it up in your oven to around 120-150°C - the supplier should state the max temp for this. If you use a gas oven or one with limited accuracy here it is best to stay within the 120° range. You need to stir and mix the gel or use something big enough like an oven tray. But be aware that these little balls are like glass! The roll and bounce like no tomorrow! IMHO it best to use an old cooking pot that has no plastic handles for this and not to overfill it. This allows for easy mixing without making a mess that might cause a bad trpping hazard on your kitchen floor tiles! Once the gel is back to original colr it is time to let it cool of to a safe temperature and to fill it back into our canister or pipe. Tanks and shut off systems.... We have a refrigeration compressor working for us, and since it was for R22 we can use much higher pressures as a simple compressor from the hardware store. The low pressure side is used to 70PSI or around 5Bar of pressure in normal working conditions. The high side often works at pressure in the range of 200-300PSI or 14-20Bar! The tank we used is a big propane tank that was restamped at some stage in his life for the use of LPG - so it was tested to quite high pressures. The lower pressure limit is what keeps the stored gas liquid at the given temperature. For Propane at an imaginary 30°C this would around 155PSI or 10Bar. The stamped test pressure, although outdated, showed 600PSI or around 40Bar of pressure with no problems - and the thing was thick in the walls... The old shut off switch from an old air compressor was adjustable after removing the safety cap with a bit of force and the help of few cold beer. With a little tank attached we adjusted it to turn the compressor off at 250PSI or around 17Bar of pressure. If your tank is old or has no test pressure stamped on do your own test in a safe location. Make sure the area is secured so there is no chance of debris from a brusting tank can go anywhere - this includes to chain down the tank itself ;) Use the aircon compressor to fill it up to 300PSI or 20Bar of pressure - this should be tolerated with ease by any propane or LPG tank. Shut the valves and let it rest for a day or so. It is best to do this in the early morning so the heat from the day will slightly increase the pressure. At the end you still want to have a working tank and no major pressure losses. All of our mods on this tank were done without actually harming the tank. This was possible as the original valve had a release port for filling purposes - as it standard on most refillable ones. Here we removed the valve and added a pressure guage instead - better to know what is happening than to assume things. As this "port" had a seperate connection to the bottom of the brass valve we added as T-connection to allow for the connection to the compressor. Just be be really sure a thin piece of copper tubing was brazed to the exit hole of this port so all incoming air will be going down and away from the outlet connection with the big shut off valve on top - which we use to actually isolate and close the tank when not it use. Last thing required was something to connect the pressure shut off switch and regulator to. That was the only major expense on this project as we had no old BBQ hose or similar to get a suitable connector to the tank. We bought a simple adapter for the use of smaller hoses and cut the unwanted bits off we there was only the bottle conntector with the nut left. After removing the rubber ring we brazed piece of copper pipe onto it. Here we drilled holes and fitted severy connectors. First for the pressure switch, then for the connection to the pressure regulator and two standard ones with a ball valve for air hose connections. One air hose connection female, the other male so a standard compressor can be connected as well or "backfilled" for additional and mobile storage use. As we wanted to avoid any reduction in the safety and burst pressure no release valve was added at the bottom on the tank. The added silica gel filter stage was used instead so no water will get into the system to begin with. Additionally, and painfully for me and me friend, the inside of the tank was coated with a layer of acrylic paint to prevent and rust as it was free from it when we checked it at the beginning. This involved filling a suitable amount of paint into it, closing the top while keeping the thread clean and then to move the tank around to cover the inside evenly. If you do this be prepared for some weird movements with your friends LOL Once we were sure all ust be covered by paint at least three times we released the exxess paint and allowed the inside to dry with the assistance of some air forced to go in with a length of pipe. This was repeated 3 times... Then another two just for the bottom third of it where there might be some moisture after all... Now you don't want to remove the brass valve with everything connected to it just to turn the tank over to releae the collected water. Instead we made sure the added pipe on the former relese port would go all the way to the bottom of the tank. If any water collection is suspected only the connection to the compressor needs an additional valve for the disconnection so the water will be force back out here. To make this easy and fast we used standard quick connectors and a piece of flexible airhose rated to 20bar of pressure for the connection to the compressor. We checked the performance of the moisture removal and oil removal only for a few hours of running time while priming some surface for later use. The compressor oil used was very smelly to say it nice but nothing coul be smelled in the first paper filter after the pressure regulator. To check for remaining moisture levels (65% humidity in the house) we used a 10m length of clear PVC tubing going through an ice bath. After 30 minutes of moderate air release there was no condensation on the inside of the tubing visible. Of course if you only need it for air supply and don't care about a bit of moisture and oil you can keep it simple ;) Benefits of doing such a stupid thing: For starters noise and the peace of mind that you can do a lot of airbrushing until the compressor needs to kick in again. Then of course the benefit of an almost silent system compared to a standard compressor - something you can actually tolerate while doing art. But the real deal is knowing YOU did it and you did it for cheap. Warnings and some advise... I know, it should be at the very beginning but I just hope you read till the end ;) If the compressor fails from overheating you are up for a new one. This means the tan size should be within the limits of what the compressor can handle - same for what you actually use on air. You want an empty tank to be filled before the compressor feels hot to touch - quite warm is fine but if you can't leave your hand on it then it is too hot. Same story for the usage. There is no point in using a tiny 10 liter storage tank if you need that capacity every few minutes. The compressor would only have little pauses and overheat quickly. You want a good balance of usage time before the tank goes below supply pressure and running time of the compressor to get it to full pressure again. This brings us to the safety of high pressures. Where possible only copper tubing or sufficiently rate hoses should be used, the later as short as possible to avoid them acting like a whip if something goes wrong. When it comes to the safety of the tank you want to make sure to stay withing it's rated limits. All benefits of a compressor capable of producing over 500PSI otr close to 35Bar is wasted if your tank and pressure regulator can't handle it. This must not mean that you try to use a gas cylinder of unknow age and pressure rating and assume it will work! If in doubt use a lower shut off pressure and stay within the limits of normal air compressors - which is around 120PSI or 8Bar. Never, ever use a tank that is compromised by inside rust or bad corrosion on the outside! If you don't know how to braze copper tubing, pipes and connectors then check out some of the great Instructables about it! Whenever you know you won't use any compressed air for more than a few hours close all valves especially the ones going back to the compressor on the high pressure side! Some compressors really don't like a huge pressure difference constantly pushing on the reed valves. If your tank is big enough to allow for more than one hour of operation before the compressor has to top it up you might want to consider a one way valve right on the compressor outlet. This will prevent any massive pressures going onto the valves - especially helpful for modern compressors that only rely on the sealing capabilities of the clyinders or rotary system used. One thing you should always consider is a pressure relief valve rated for about 50PSI more than your tank pressure - it can be added to the pipe ;) If the shut off valve ever fails the relief valve gives you the ease of mind that it will blow before your tank does. Maintenance... If modded correctly the compressor should stay in the compressor and the compressor itself should not overheat from use. Having said that your compressor might force out a little more than your best catch system can handle. If that becomes a problem it might help to use an oil with a lower viscosity. If all fails it just means you need to top up oil once the last last paper filter is filthy or use slightly more to begin with so the intervals are longer. The silica gel, if used should be recharged before all of it is wasted - no point in adding it if you use it once full of water. If no gel is used there will be water in the storage tank. Even with the added paint and a good air filter it is possible that nasty things grow in there. Making sure the tank is emptied of any water after long uses and again before the next use is good practise. If no pressure gauge is used on the tank you must make sure the shut off valve is always working fine and within set parameters. I strongly recommend using a gauge and if not to perform a pressure check of the system every now and then to confirm all is within parameters of normal operation. A compressor constantly running means you either use far too much air or you have a leak - same story if the compressos kicks in after some of forgetting to shut it off and close the valves. If you keep the above in mind the salvaged compressor should work just fine for many years to come. Troubleshooting and alternatives.... You put everything together the right way, double checked and something is till not right? Maybe my crystal ball helps me to find something... 1. Always oil coming through the catch system. It usually means you use too much of it. A salvaged compressor, if the refrigent was removed legally from the system should still have a "correct" level of oil inside. Too much oil would mean is being pumped through the system at an excessive rate. Very thin compressor oils tend to do that in the compressor is misude like we do. Changing to standard mineral oil can help here. As a last resort you can use a pressure gauge or good judgement to allow more flow through the needle valve from the catch system back to the compressor. Too much backflow here would mean we loose system pressure to the set level of this needle valve! 2. The R22 rated compressor seems to be unable to produce enough pressure. First do a leak test using soapy water to rule out any leaks. Do a back pressure test on the ports. If you can push air through them in the reverse way with ease it means the valves are damaged making the compressor useless. You need to replace it. A regular cause with our type of usage is a constand back pressure from the storage tank to the compressor. To prevent this it might help to mount an electric solenoid between the compressor and storage tank. Such valve should be off when the pressure switch is engaged and on when the pressure switch is disengaged. This prevents the coil from overheating but requires a "normally off" type of valve. A good source at the wreckers are cars with LPG systems installed, they usually have suitable 12V valves somewhere on or near the tank and filler cap. 3. I am using several kg of silica gel but still get a lot of water in my storage tank. Going overboard in a humid climate can be a good thing here but if moisture makes it into the tank even with great amounts of silica gel there are only two causes: a) the tube or cylinder used is not long enough or not wide enough to allow the absorption of all the moisture going through. b) the flow rate is too high and the temperatures are too. For the first the solution is obvious enough. The second is related to the first for the diameter and lenght but temperatures constantly above the 30°C while operating somehow limits what the gel can do. Using a cooling coil on the intake side or simply putting the gel containers in icy water will help to a great deal here. If that is not an option than I suggest to layer the gel and to seperate it with fine paper filter screens. This will slow and even out the airflow allowing for more contact time with the gel. 4. The compressor gets very noisy after some time. If "some time" means more than 30-45 minutes you simply have it running too much and it overheats. If the noise increases too much when reaching the shut off pressure it can mean the pressure is too high for it. 5. Can I use multiple compressors from smaller units or refrigerators to get enough air volume? Of course you can but it might mean you have to lower your pressure expectations. Consider that each individual compressor would get the back pressure from all other compressors running while it's outlet valve is closed. To avoid premature failure you want to make sure the compressors are shut off at a lowver pressure. 6. I don't want to use a big tank but require a good airflow for airbrush. Two or three fridge compressors working one after the other with a small tank to keep the output pressure even can allow for about 30 minutes runtime per compressor. With three it gives one hour for the the first to cool off and should be enough for ongoing work. Downside is you need to make some sort of automatic switch to "rotate" to compressor working. Last words.... Is you find any spelling mistakes you can keep them. However, if you use them in any way to make a profit with them I kindly ask for 10% of your earning from it ;) Why did I not make an Instructable out of all this? Well the day was very hot, the beer very cold and my mobile phone at home, so I did not take any pics. To top it up the whole thing is now in a seperate box for additional noise reduction so it can be used in the same room where the guy is working. Of course he just used a nailgun for the job without any regard of access or at least easy view of the two pressure gauges. Typical if you have a great idea and the cold beer tells you to forget all about screws or hinges ROFL Only comment was: You created it and it works fine, why would need more than the pipe connections for the gel and regulator? Maybe he will reconsider when the service is due....

Topic by Downunder35m    |  last reply