"It Will Be Awesome if They Don't Screw it Up"

Public Knowledge recently published a white paper on 3d printing (see link for downloadable PDF version). It compares low-cost home 3d printing technology with home computing and digital publishing, with specific reference to the possibility of DMCA-style legislation preventing the technology reaching its full potential. In many ways, today’s 3D printing community resembles the personal computing community of the early 1990s. They are a relatively small, technically proficient group, all intrigued by the potential of a great new technology. They tinker with their machines, share their discoveries and creations, and are more focused on what is possible than on what happens after they achieve it. They also benefit from following the personal computer revolution: the connective power of the Internet lets them share, innovate, and communicate much faster than the Homebrew Computer Club could have ever imagined. The personal computer revolution also casts light on some potential pitfalls that may be in store for the growth of 3D printing. When entrenched interests began to understand just how disruptive personal computing could be (especially massively networked personal computing) they organized in Washington, D.C. to protect their incumbent power. Rallying under the banner of combating piracy and theft, these interests pushed through laws like the Digital Millennium Copyright Act (DMCA) that made it harder to use computers in new and innovative ways. In response, the general public learned once-obscure terms like “fair use” and worked hard to defend their ability to discuss, create, and innovate. Unfortunately, this great public awakening came after Congress had already passed its restrictive laws. Of course, computers were not the first time that incumbents welcomed new technologies by attempting to restrict them. The arrival of the printing press resulted in new censorship and licensing laws designed to slow the spread of information. The music industry claimed that home taping would destroy it. And, perhaps most memorably, the movie industry compared the VCR to the Boston Strangler preying on a woman home alone. One of the goals of this whitepaper is to prepare the 3D printing community, and the public at large, before incumbents try to cripple 3D printing with restrictive intellectual property laws. By understanding how intellectual property law relates to 3D printing, and how changes might impact 3D printing’s future, this time we will be ready when incumbents come calling to Congress.   Podcasts and videos on 3d printing. Gothic Cathedral play set. BBC reportage. Freedom of Creation (3d printing designers)

Topic by Kiteman   |  last reply


Did I screw up my power converter?

My motorhome has a115v ac to 12v dc with a split transformer, the 2 outer leads went to press in diodes and the middle lead went to neg or pos.(cant remember witch)  it is 40amp converter. one of the diodes was bad and i was only getting 6 volts out so i replaced them both with 40 amp 600 volt ZENER diodes. Are the zener diodes the wrong type to use, all seemed good except my neg and pos polarity were reversed coming out of the power converter, I reversed the terminals at the hook up so polarity would be correct.  Could this discharge my battery when its not connected to 115v.                                                                                             Thank you, Duncan

Question by dsr.   |  last reply


What is the oil content of Eurasian Milfoil?

I would like to use the oil extracted from Milfoil to produce biodiesel. I would like to know what the oil content, if any, is of milfoil. I think it is great because it is unwanted and there is a lake near me that has two giant machines whose sole job is to cut milfoil. I could collect it, dry it, press it, and refine it for next to nothing. If you have seen anything like this let me know.

Question by jack.h   |  last reply


where to get small plastic gears, to OEM spec?

There was once a nice Cyberhome DVD player that was cheap and fast and good, but then the pinion gear on the laser carriage motor split, and suddenly it became a piece of junk. I found many sources for small gears, but not the right one. This one is a 12 tooth, 2mm bore, 6mm dia, 6mm tall item that press fits onto the shaft. Based on other posts on other sites, these players are electronic lemmings, and are all soon destined for the dumpster, mostly for this reason. HELP ME SAVE THEM FROM THEIR FATE! Perhaps we're all screwed, and this is not an off the shelf item.

Question by Fixerdad   |  last reply


Would this automatic curtains / blinds controller design work?

Hi all, I have been searching for ways to make an easy and cheap automatic curtains/blinds controller but have not really seen any that actually meets my basic needs but also does not require lots of complex IC components. Please let me know of any instructables I may have missed. So here is my design - hoping everyone can help to validate it and discuss design faults and improvements (mainly to reduce costs). The Requirements: 1) Costs: Total costs should be around $20 per curtain. I think professional systems cost about $100-$200 per curtain controller. 2) Parts: Easy to build and put together with some soldering. Parts are easy to find/buy or substitute for similar components. 3) Function: At least 2 buttons. One UP button and one DOWN button for manual triggering (wireless buttons would be better). 4) Function: One press of Button A fully opens the blinds with the motor stopping at the correct place to avoid damage to the blinds or the motor. The opposite goes for Button B to close the blinds. 5) Function: The controller should never be able to open or close the blinds past the normal safe positions, causing damage. 6) Optional Parts: Complete system is small enough to fit inside the blinds/curtain's cover / awning. I think it should be easy to fit in most covers anyway. Briefly how it should all work: With the curtains rolled up, you would press button A, which would roll the curtains DOWN, then stopping at the correct place (covering the whole window). Pressing button A once again would not do anything or further roll DOWN the curtains. Then, press button B and the curtains should start rolling UP constantly, stopping just before it gets to the top. Pressing button B once again would not do anything or further roll UP the curtains, avoiding damage to curtains or motor. Design/diagram below (sorry for the poor details, i used MS-Visio to draw it out). The Parts/Components (under $30 at time or writing): 1) 5-10kg servo $7 (using 5volts) that can be power in forward or reverse spin. Slow spinning speeds would be best for safe and low power operation? 2) Some hand made adapter to firmly connect the servo motor shaft to the curtain's shaft to spin/roll the curtains ($0 free). 3) A wireless power relay $14, (12 volts) with 2 channels and "constant on power" functions (links below). I guess wired relays are fine, but I would want to hide the wires to the buttons. 4) 2x 5V regulators $2, to reduce the 12v power from the Relay to 5v for the Servo. 5) 2x Magnetic or reed switches $5 (12 volts) that is Normally On (normally connected). 6) 4x Rare earth magnets $1 to work with the reed switches. These are small, thin and easy to hide, but are very strong. 7) A power source for the relay, 4x 18650 batteries?. Should be 12 volts or depending on what relay & servo combo you use. (links below) Construction: 1) Make an adapter to connect the servo to the blind's shaft. I dont have a picture of one or the steps for this as every servo & curtain combo situation will be different, but im sure it should be simple to make. Fail or malfunction of this part would cause too much damage to anything really? 2) For best practice, use temporary wiring to connect all the components together as per diagram and test out the functions as if they were installed in their places and on the blinds. 3) Glue or connect the adapter, curtain shaft and servo shaft together. Also mount the servo firmly somewhere, on the wall or curtain cover so it doesnt end up spinning itself. 4) Position both magnetic switches on the wall, behind and just under the curtain's roll of fabric as per diagram. A lot of testing and playing around will be needed to create the correct gap between each switch and curtain.    Switch A   (Limiter A) will be the most difficult to position. It will be used to stop the servo from rolling the blinds too far down. This means the magnet glued on the blinds is up high on top, which will be rolled inside layers of fabric and may spin close to Limiter A multiple times which may cut the circuit/power earlier than intended as the magnet spins round and round. Limiter B should be easier. 5) Wire the 2 channels on the relay to the Servo and the Limiters. The 5V regulators goes between both channels of the Relay's power OUT and the Servo's two power Inputs. Screw or glue the relay to somewhere firm like inside the curtain covers. 6) Glue the rare earth magnets to the desired positions, or sew them on if you dont trust the glue. The magnets will physically cut the power to the servo by activating the Magnetic reed switches, so using 2 magnets would be even better, just incase the servo you use spins really fast or has a lag. 7) Connect the relay to the battery/power cable. Of course double check all is good before adding power. In my case, I will have 12v power cables available to use. 8) Put the curtain cover back on to hide everything. Hopefully you did not create creases in the curtain fabric where the magnets are glued. Oh and maybe remove the curtain draw strings (used to pull up & down the curtains) to avoid breaking the Servo? Detailed explanation of how it should work: - The blinds are fully rolled up. - Press Button A once, Relay provides power to Channel A, Servo spins clockwise constantly (rolling down the curtain). - Servo's positive line A is cut (circuit open) when Magnet A rolls out and comes close to Limiter A. Relay is still outputting power to Channel A but no power goes to the Servo. - Press Button A once again, the Servo should not do anything. The Relay should then stop outputting power to Channel A. - Further presses of Button A does nothing but toggles Channel A's power on and off. Magnet A & Limiter A still disabling power to the Servo. - Press Button B once, Relay provides power to Channel B, Servo spins anti-clockwise constantly (rolling UP the curtain). - Servo's positive line B is cut when Magnet B rolls up close to Limiter B. Relay is still outputting power to Channel B. - Press Button B once again, the Servo should not do anything. - With this "latch" functionality of the Relay (see link below and product details), it is also possible to stop the curtains mid way, which might be useful for some people, i dont think i will use it. For future upgrades: I think it would be possible to control this controller from a PC program, by directly connecting IO cables to the Relay's button A & B on the PCB. Sending pulses from the PC as though it were remote button presses. Or just bring the remote to the PC's IO ports and connect there. Would anyone disagree? Links: - An example Servo: http://www.ebay.com.au/sch/i.html?_nkw=High+torque+Metal+Gear+RC+Servo - The wireless Relay: http://www.ebay.com.au/sch/i.html?rt=nc&LH;_PrefLoc=2&_nkw=2CH%2012V%20Wireless%20Relay - The 5v Regulators (L7805): http://www.ebay.com.au/sch/i.html?rt=nc&LH;_PrefLoc=2&_nkw=5v%20regulators&_fln=1&_trksid=p3286.c0.m283 - The magnetic reed switches: http://www.ebay.com.au/sch/i.html?_nkw=reed+switch - The rare earth magnets: http://www.ebay.com.au/sch/i.html?_nkw=rare+earth+magnets+n38 - Design/diagram: http://i50.tinypic.com/118emas.jpg

Question by sonhy   |  last reply


Algae oil

I've been reading about biodiesel and about using vegitable oil from algae. It would seem that per acre you can produce 250 times as much vegitable oil using algae than soy beans. I've been looking into the necessary parts for a very small scale demonstration project, including production, harvesting, drying and converting oil into diesel, but I'm having problems finding information of oil extraction. There are some very large oil extractors using screw and expeller. Even a very small one would cost several thousand dollars and since it is made for seeds I'm not sure it would work with algae. Does anyone here know about oil extraction process and how it can be scaled down and used with algae? The system I envision would only take the first pass in extracting oil, about 70%. From what I've been reading it is possible to get another 25% but requires some very nasty chemicals. Also, taking only that first press, the leftovers (refered to as "oil cake") makes for an excellent animal feed. After extracting that last 25% the leftovers are no longer suitable because of the toxic chemicals used. I'd rather have the 70% and animal feed and not have to bother with some very elaborate procedures for handling toxic chemicals. Anyone else interested in helping to put together a demo project like this? I already have resources on converting voil to biodiesel. Like I said, I'm mostly looking for information on extracting the oil. Thanks

Topic by GlobalVillageIdiot   |  last reply


Options to improve cooling and reduce consumption for portable coolers

I recently had to start learning how to service airconditioners on the fast and that learning got me thinking about my portable coolers.... Some of us like to go camping or on longer fishing trips, so there might be one of those 3-way fridges in use or a better cmpressor model. The one thing they all have in common is that they can only cool down to a difference in ambient temperatures. No matter which way we turn it the cooling produces heat and that needs to get away somehow. The other big thing is the cooling cycling - or the lack of it on a warm day. After some reading and thinking I came up with some ideas that might be applicable to your existing cooler if you are willing to mess around a bit. Let's start with the produced heat, shall we? Down here in Australia most people either have the fridge in their4WD or camper. In a car or small camper trailer there is often the problem of airflow, so the cooler might be doing overtime for no other reason than a lack of airflow. If you check online sites like Amozon and Ebay you quickly find fan systems meant to be installed inside the cooler to get lower temperatures and a quicker cooling of fresh goods. The thing is that the box is quite well insulated and the benefit of the airflow goes only as far as it can reach. And even if the box is quite empty and you would have a benefit of the cold air moving around it won't change the fact that "improved" cooling always comes with more heat in this case. But if we use one of these fan systems to actually improve the airflow on the hot side we not only get better cooling but also a reduce power consumption - something worth considering if you have no backup power generator.... This of course brings us to placement. As I have done the mistake myself you might be tempted to put a 3way cooler onto your seat. Opening it with the back free means the lid always gets stuck on the seat, do it the other way around and you block the airflow. If you do put it on the seat then make sure two things match: 1. The thing is secured properly. 2. The airflow from your aircon is able to reach the hot side of the cooler. Even permanent installations in a camper benefit from a good airflow. Often the fridge or freezer is built into some sort of bench and the airflow behind might be very limited. A simple solution here is to add a vent on top of the bench to allow the hot air to escape. A better one is to use a fan that is powered together with the heating element or compressor and drives the hot air to the outside. How to improve the cold side of the box or fridge? Well, to be honest there is not much that can be done unless you are prepared for some serious work. Depending on compartment size, contents and how full it is a little fan can help to keep the temperatures even but it won't help to get it cooler or reduce the cycling periods for the cooling. The only really working way that I found is to use a "battery" for the storage of the cold. The cooling works by checking the inside temp of the box and if above the set temp the cooling won't stop. This is all well and good while we have a constant supply of power but once we are on batteries it would be great to keep the active time to a minimum. A working solution is to build a container that fits around the cooling element. Smaller types often use an aluminium heatsink, bigger types might come with a compressor and an evaporator. In either case proper sealing is important! Most good models are fully waterproof, meaning even if you would fill them with water they would not leak in other areas than the door. But double check and if in doubt use a bit of silicone to make sure. Ok, but how do we "store" the cold coming from the device? Cold packs ;) These things contain a ready to use mix that holds cold temperatures quite well. Another really good alternative is alcohol or radiator coolant, although the last has limited capabilites in terms of holding capaity for the cold as it is desinged to exchange heat fast rather than to keep it. With a suitable sized and sealed box around the active cooling element we will need longer to actually see any cooling happen (with a warm "battery") but that can be compensated for by good planning or a frozen water bottle. If the cooling element is covered with a box of cooling gel then it has to cool this first before anything happens inside the box. But once it does the pack is already far below the normal temp it would have during normal operation. Remember the inside of the cold pack cools down first before the outside will get cold ;) So once the set temperature is reached the device will shut off. But since the cold pack is far below the set temp it will continue to cool our box until the core is warmer than the set temp. Quick thinkers will now say the benefit is lost as the time required to cool the "battery" down again is much longer than the normal cycle time - and they would be correct. But as we get much colder temps inside the gel box the overall running will still be less compared to normal operation. And since from the second cycle on the gel is only warming up to operating temp of the box it will be much faster than with a warm box. Another benefit might be the ease of cleaning and ice removal. Some peltier driven coolers have big cooling fins or a quite bad design for the heatsink allowing mould to grow where you can't remove it easy. If the box is made from stainless steel and flush with the back wall of the box we won't have that problem anymore. Ok, but how much is good or too much for the size and gel content? You got me there as it is bit tricky. You don't want to loose much usable space for starters and you don't want to wait hours for the gel to cool down if the box was not used. IMHO the size should fit the cooling element with about 20% to spare all around. If stainless steel is not an option than aluminium is the next best choice. Thin sheets can either be be cold formed with a hammer or "brazed" with a good torch and the right rods. Ok, before that route is there anything I should consider or do first? Depends ;) 3-way systems usually use a flame or heating elements to heat an ammoia solution. After years of neglect corrosion can form and reduce the amount of heat transfered into the system and reducing the efficiency this way. It might help to take the heating elements out once a year or so to clean them and the contact areas from any corrosion or dirt build up. With a fixed shedule for this you won't have the problem of never noticing a badly corroded heating element either - and this is the main failure on these systems.... Modifying your camper or making a few mods to your 4WD drawer system is not for the faint of heart and should be done with consideration. The last thing you want to do is rush things to find out it was not necessary. Before cutting holes check if you can't find the room for the fan in a different spot and use ducts to control the airflow - sometimes it is easier to blow air in than to get air out ;) When it comes to creating vents or connections for air to the outside always make sure it is waterproof and insect safe! If you can let the outlet go downwards so water won't run in, for 4WD trailers consider a flap to prevent water from going during a river crossing. Flyscreens will not only prevent insects from coming in but on the inside also prevent dust to go eerywhere - allow to the removal and cleaning! The salts used in these cold packs can be corrosive, so you have to make sure there are no leaks and that there is no steel to come into contact with gel - this includes screw ends hidden in through-holes. If in doubt use a coat of paint but keep it as thin as possible. Even on peltier systems it might be impossible to remove the heatsink without massive surgery on the internals. So before you take it all apart to gain access check if it is far easier to seal around the box opening and possible screw connections using silicone. The cooling battery can be screwed on and sealed with silicone as well as an easy escape route. Although for this to work you need to check if the material of the box allows for a proper bond with the silicone! Some materials just won't allow anything to stick at all, even after sanding them. So do a test first in an area where you would be able to cut the silicone away without causing damage. If you can rip or peel it off the surface you should not try to use a cooling battery screwed to the wall, only use a box that is fully sealed with the cooling element and has a seperate back - one complete unit around the cooling element. I have a 3-way system with a freezer compartment that does the cooling for the fridge too - what can I do? These units either provide good freezing with the fridge temps too low or good fridge cooling with no freezing capabilites - depending on the thermostat used. Our problem is that is next to impossible to add a cooling battery of the normal kind to these systems. The L-shaped freezer box can really only be added with a L-shaped cooling battery from underneath. Only if you don't need any freezing at all you could add a cooling battery to fit into the freezer box shape. In either case the benefit is somehow limited by the way the thermostat is used. If there is no temp control for freezing it should be fine. Warnings... Only peltier driven coolers are free from refrigerants. Every 3-way or compressor system uses refrigerant as evident by more or less piping and heating elements. Never attempt to screw anything into a cooling element containing refrigerant! Even if you think between the channels all will be fine it won't be! The material is just pressed to form the channels and any damage caould mean refrigerant leaking out! Use silicone instead and make sure all surfaces are properly cleaned before applying it, also wait until the silicone is really fully cured before putting any stress on it. As said, these cooling gels can be corrosive, especially if DC voltage is involved. Make sure that everything that is not aluminum or plastic is properly sealed before allowing ongoing contact with cooling gels. Do not attempt any of this if you have to ask yourself what tools you might need or how make a suitable container for the gel. If in doubt check Google on how to work with aluminium or stainless steel if there are not enough Instructables for it. The gel will expand a little bit if it freezes, this no problem in a metal container if you allow for a bit of flex or on the side added strength  - whatever suits you better. Another option is to get a few different cold packs (by the active ingredient) and to do a check in a little container. Freeze it and note whe level cold and warm. Little to no difference means nothing to worry in terms of expansion during freezing.

Topic by Downunder35m