Topics


Push button to start / stop recording with a webcam?

I want to make a "2 buttons recording machine" with a webcam and a display. It can be on Pi or PC. I could not find much useful information that tells me how to use a button to start/stop video recording. Can some one help to make this? or any useful resources for "pushing button to record video"

Topic by rootloop    |  last reply


Can you melt silver at home (for jewelry)? Answered

I want to melt metal, preferably silver, to stamp in the process of making jewelry. I want to know the process and the materials/equipment needed.

Question    |  last reply


Solved! Desperately searching for a project

Found it! https://www.instructables.com/id/Ductiles-Interactive-Graphic-and-Message-Board/Hi GuysAbout a year ago I saw a cool project that I can not find again. I have tried dozens of tags (typo picture/wall art/letter/game/puzzle/mosaic/grid...) and crawled many many pages but no success... please help. It was a kind of typography picture with replaceable wooden tiles on a grid, maybe 10 x 10 tiles. You can combine the different tiles to form a letter/character or a geometric shape/picture. A little bit like a "typography wooden pixel art mosaic" I would be very happy if someone out there remembers this project and shares a link with me. Thank you!

Topic by Tobotron10    |  last reply


Need help designing a current limiting circuit for a DC powered device.

What would the simplest and most energy efficient circuit be to limit the current from a DC transformer?  I have several 12-15VDC plug-in transformers that deliver between 800-1000mA, but a device I need to power requires 12-15VDC at 350mA MAX.  Any thoughts, help, or advice would be appreciated!

Question by AJackOfAllTrades    |  last reply


How do I get compression into my engine?

I have a 2000 Grand Am Pontiac 6 cylinder. I have low to no compression in my engine, i haven't got a compression test done, at first I thought it was because I had a hole in my radiator hose, but i changed that along with my battery and both are perfectly fine, but car still won't start. It makes the sound like there is no compression, so I was wondering how do you get compression back into an engine. I spoke with a mechanic and he said that i could pour transmission oil into the spark plugs and that should do, I just wanted a second oppinon and see if there are any other ideas.

Question by BriLaneaC    |  last reply


IOT communication from one Arduino to another

Hello, my friend and I had a idea but neither know how we would do it. Our thought was to build a system that would allow us to connect telegraph keys to Arduinos and use the IOT to allow us to communicate from our own houses in Morse code without having to use ham radios. https://getappvalley.com/ What we are hoping to achieve is a as I send a dit or dah his system tweakbox would sound it in real time. We would like to avoid using a system where I type the message in full and hit send. How could something like this work? tutuapp

Topic by VoltarGomes  


"Secrets" about CB/UHF antennas on your car

Despite more and cellphone and internet coverage mobile radios are still a favourite of people in remote areas or just loving to explore by 4WD.And for most the complex task of starting with this great hobby ends by buying a radio and antenna.Of course the raio goes it fits best and that is fine but what about that antenna and while at it what type of antenna do you need?Let's start with the great myth that so called rugged or heavy duty antennas are really worth their money.Durability and stiffness is their main selling point or better was.At highway speeds they won't bend and flex around like your whip antenna.In the bush they won't swing all the way down onto the painted parts of your car either.But then again, a more solid steel whip on a spring base would do the same - but won't look as cool or proffessional...Inside those plastic or fibreglass rods is a dipole antenna, in rare case you get a 5/8 configuration or even a normal steel whip with a pipe around it...Means in terms of reception or transmission quality they are not a tiny better or worse than any other antenna out there.Come down to well it is tuned and where the radiating part is located.Location...There are often obvious choices to put an antenna, like that nice mount or your nudge- or bull-bar.Or the good old boot clamp in the back.I have even see 4WD's with the antenna mounted onto the rear bumper :(Why is it so important to place the antenna correctly?Place on the front corner of your car it is not only quite low but also partially covered by the metal parts of your car - limiting where the antenna can properly radiate.If you ever got some half decent training on a tiny handheld UHF radio then you remember to seek higher ground if you can't get anyone to hear you.The same is true for the antenna on your car.You want nothing obstructing it.People with a long spring base often think of it as just an elevated foot.Most of these however are "ground idependent", which means they actually form a dipole with the antenna you screw on the top.Having this "pole" below bonnet hight is quite bad for your reach and reception quality already.Mounting just a normal whip on a direct foot here means you might have better luck with a handhelp from inside the car...The best would be right in the center of your roof, the highest and most centered point.This provides not only the optimum radiation pattern but also give you that little edge in terms of higher ground.How much gain do I need and how long should my antenna be?Gain is quite relative if you ask me as it far more important to mount the antenna in the best possible place.A 3DB antenna on the roof will often provide better reception and range than a 9DB mounted on the bullbar.Assuming you have the best feasable location than to simplify it:The further you can see the higher DB you want if reaching far is the main objective.For general use a 4.5 - 6DB antenna is always good.In hilly terrain range does not matter that much, here you want the outgoing signal to be as strong as possible and with a shape that allows better coverage by being more like a sphere.For extreme cases it can mean on a 9DB antenna your friend that is just over that little bump ahead is not visible and with that can't hear you.On a 3DB antenna however the signal is strong enough to reach that blindspot at a short distance.The overall length of an antenna can be deceiving for UHF frequencies.What matters is where the antenna is radiating from.In most cases it will be the top 15 to 30 cm of your antenna.For a dipole or ground independent antenna you often need to include the entrire base mount.Antenna tuning....For the good old 27MHz bands we always had our SWR meter at hand and tried to get the best tuning.Since the big jump to UHF the commercial antennas come pre-tuned and are claimed to be good to go.That means that are within acceptable performance to fit almost all installation locations.In terms of SWR reading it means that 1 over 3 is still perfectly fine.Would have been an outcry on 27Mhz though in my times.What is true though that there is not that much real difference to notice between a near perfect 1 over 1.1 to 1 over 3.If you would bother to a distance test it might be less than 200m you gain on the near perfect antenna.For the reception it does not even matter all, so why bother anyway?On the much lower frequencies a really good SWR does not only mean you can get your signal much further out there but also that your transmitter is happy.Modern ones are now all digital and have ways to protect and compensate for bad antennas or cables.Together it means we could just forget about these few extra meters and move on.The stress on the transmitter in your UHF radio however is still there ;)The reflective energy from a badly tuned antenna has to go somewhere and that is usually back into the transmitter.The bit that lost directly to your antenna, as said, does not matter too much with the overall limited range of the UHF frequencies.I did quite a lot of experimenting with my own and commercail UHF antennas, so a network analyser and SWR meter was a requirement anyway.In terms of output power a good SWR reading means you get what your transmitter is capable of and set for.With an SRW reading between 2.5 and 3 however a 4W radio might only actually transmit 3-3.5W.With a bad mounting and an not so optimal cable it might go below 3W!Distance is not so much affected by this as we now know, but the loss in power on 3DB antenna in hilly terrain can make the difference between being heard and your signal getting lost in static on the other end.Repairing a blown transmitter often costs more than a simple SWR meter for UHF, so why not add it to the Xmas wish list? ;)Two antennas...In some case you want two antennas.Be it for two different DB ratings on the same radio or for totally different frequencies.High and centered is still best here but you should keep the antennas as far apart as possible, preferable at different heights as well.On a single radio it does not matter too much but right next to each other the unused anteanna is like these beams on your TV antenna on the roof.Unlike the directional and watned features in a Yagi antenna the unused element means we change the radiation pattern.In the worst case creating a blindspot from which direction we won't get any signals.As a rule of thumb let them be apart at least twisc as far as the wavelenght, so for UHF over 65cm.

Topic by Downunder35m  


How to automatically lift an object to an arbitrary angle?

How to raise the hypotenuse of the triangle to an arbitrary angle. I had a project like that but I couldn't do it because I was new to it. Tools in the project include inclinometer and servo motor. Please help me please. Sincere thanks

Question by DanhC2  


Building a circuit to flash an LED for 30 seconds, once every hour

Hi, im trying to build an integrated circuit for a device that will flash an LED for 30 seconds and I want it to flash every hour. I'd prefer not to use a microcontroller if possible and just use integrated circuit components. I've looked at oscillators but found none that have such a small frequency. Any advice?

Topic by JenrasGomes    |  last reply


Cant enter instructable in contests

Help I cant enter my instructables in contests. I have just published an instructable. For some reason when I click on any of the contests to enter, I get a pop up about "In order to enter this contest you must be logged in and have published an instructable since the launch of this contest." and I have no way to enter. The instructable was just published. Some of them close tomorrow that I want to enter. Can I get some help

Question by GunGeek369    |  last reply


Does the embed video in the editor work for you?

I've been trying to create an Instructable that includes a video I posted on YouTube, but after going through the process of embedding it in the Instructable editor, it seems to convert it to a photo every time I hit publish. I have reviewed the "How to use the Instructables Editor" several times to see if I'm skipping a step or something. Here is a link to the video:https://www.youtube.com/watch?v=yqfPuwQO0-Q

Topic by WayfinderAli    |  last reply


how do you disable the speed governor (limiter) in a car? Answered

How do you disable the speed governor (limiter) in a car? No specific car just wondering the different ways, and what actually tells the limiter to kick in?

Question by i make shooting things    |  last reply


how do I put a microphone at a bird feeder and listen in the house?

This would be very similar to a baby monitor.  Is there a way to transmit the signal from outside to inside the house?

Question by Petie    |  last reply


Does anybody know of a Canadian source of buying KNO3? Answered

I have looked everywhere in my city and cannot find anywhere that sells stump remover or any other potassium nitrate product. If somebody says "look at lowes" they should be ashamed =PI have looked at Lowes, Home Hardware, Canadian Tire, Home Depot, and every other garden supply center around.

Question by FunkNattidelic    |  last reply


eski - Autonomous Foosball Table - Universal Laser Cutter Finalist!

To see who won the VersaLaser, read the announcement here.eski was a finalist in the 2008 Instructables and Universal Laser Cutter Contest for:Autonomous Foosball TableShould this project win the grand prize VersaLaser laser cutter package from Universal Laser worth over $15,000? Help us judge the contest by rating this forum post! Audience votes will count for 20% of the total. Check out all the finalists, and vote for your favorites!This is a forum post created by the Instructables staff on behalf of the finalist. Thanks for all the support everybody!

Topic by eski    |  last reply


3D printing filament recycling guide

If you print a lot then you also have a lot of plastic to waste.Support structures, brims, failed parts....At some stage you start to wonder if it makes sense to invest into a filament extruder.A filament extruder is a simple way to make you own filament.A 25kg bag of granules in ABS cost only a few bucks and it will last like forever.It also the prefered choice for a plastic extruder of any sort - fresh, new and clean material!I do collect a lot of leftover plastic from my projects, is it worth getting a machine to recycle it?Trust the advertisements of the commercially available models you buy one right away - if you can afford it...But there is always a catch!What are the basic requirements when collecting you already used filament?It would be easier to state what you should avoid at all costs, so let me start with the most forgiving filament types - ABS and PLA....Both will require that you keep your filament clean at all costs.You want dust removed before the filament even enters you print head and same for all that you want to recycle.Conatminents are the biggest deal breaker when you recycle filament!!!That means parts of dissimilar materials,like when printing with two heads are just rubbish and go in the recycling bin outside.The difference between ABS and PLS for recycling comes with the material properties.ABS, if not printed too hot does not change too much, PLA on the other side usually ends up to be more brittle than new filament.ABS should not be heated too high, same for PLA when you recycle.But when PLA gets too hot it not only becomes really runny but also deteriotes very quickly.Run a bit of PLA through print head like when changing filament or cleaning the head.Do one run at normal temperatur, one run at 240°C and compare how the extruded and colled string reacts ;)PLA is also prone to oxidisation and burning, espcially the black type is tricky here as you won't be able to see it, so avoid black if possible.If it happens then you end up with rock hard piece, the size depends and can be tiny or bigger than a grain of sand.A total nightmare if you did not spot that black spot in the filament and let the recycled stuff run through your printer.A total block of the nozzle is the result.Nylon I can't really recommend for recycling, too complext to handle it properly.Same for filled filament like the wood or metal types.With them it is really easy to accumulate a lump of filler that does the same block to your nozzle.To wash or not to wash....No matter what you try there will be always some contaminents that end in your collected material.ABS can be washed with water and does not require too much fancy drying.If in doubt you can even try your dishwasher or with a good bag your washing machine - both require proper rinsing several times and the last run with some added alcohol to demineralised or destilled water.I use a box with a flyscreen cover and let it dry outside in the sun for a while.PLA does not go too well with water especially with added soaps or detergents.On the other hand it has no big problems tolerate things like Acetone.Downside such solvents also dissolve a lot of contaminats which mean even though you can recycle your washing Acetone many, many time you always need fresh Acetone for the rinsing.If you can try too keep all as clean as possible to eliminate the need for washing.Can I get better results from my cheap filament maker or the one I build for some online instructions?I find that there is always room to improve on things.Before you even think about extruding your home made filament think about how to get your failed print into the thing ! ;)The most vital part comes before you even heat the machine unless it is a really fancy one with a build in and big enough shredder.That is right you need a shredder of sorts to be able to get your recycled material fine enough for the filament maker.Some models you might quickly find as tutorials to build your own use basically a big wood drill for the mechanical part to simulate a meat grinder for plastic.Even the better ones for real money often use this basic system in one way or another.The problem is that you need to get all air out the material before it ends up to be the outgoing string you roll up.Any bubbles in filament will certainly have consequences if the bubble appears during the printing of visible areas.Imagine printing in vase mode and hitting a bubble during the last 20 minutes of a 3 hour print...Unless it is dirt simple hobby built there will some mechanism to deal with the air.However if what goes in is already very fine material it melts easier and air has it a lot easier to find a way out.A good shredder will produce quite small granules but not strips or blocks.The have their limits for intake size though.The best way to get through bigger builds is a band saw, if have a clean table you can even recycle the "saw dust".I prefer to heat bigger parts in the oven at moderate temps and then to use a hammer or press to flatten it first.No shredder or no money to add one to the list? No problem!If your filament maker does not have a pre-heated feeding area of sorts it makes sense to add one with aheating mantle and external temperature controller.Trust me, if you have odd stuff to push in it is way easier if the material softens already before it enter the extruder drive part.As the extruder will get quite warm anyway it can be as simple as adding a short pipe section with the heating mantle between the extruder inlet and feeding funnel or hopper.the temperature in theis areas should of course be will below melting point and slightly above the temp when the material start to become plyable.Hence the external temp controller here.With this heating in the fedding area you really need to get your recycled material into a suitable size and shape to allow the material to be transported easy into the extruder.Ok, I got it working, sort of...You will need some time to find the prefect temperatures for per-heating, extruder temps and coooling, so take it!If your filament comes out with bubbles or fine (hard and unwanted) particles it makes sense to cheat.Most filament makers include a filter before the melted material enters the nozzle and really hot part.In some cases this filter can be as simple as a steel mesh.If none find ways to add one ;)Said filter screen should be quite fine, preferably even finer that what you find in your faucet that airates thewater for the sink.As a rule of thumb the mesh size should at least 15% finer than the nozzle size you intent to use.Anything that makes it through will only be a problem for your nozzle if a lot of crap comes through and that you should be able to spot right away when the cooled filament comes out.If despite this you still get too many bubbles check first if your temps are not going too high so the plastic start to boil in an area.Too much speed can also cause a failure to expell all air in time, reducing the speed (watch the temps!!) can often resolve this nagging air problem.It it really worth it then?On a hobby level only if you print a lot and know you will keep going like this.Otherwise you really need to be able to source or build your filament maker as cheap as possible.Someone with a little print shop and three machines running 24/7 will certainly have a good benefit over time.Especially if the recycling is part of the overall printing process.Recycled material could be used in a dedicated head and extruder for supports, infills and so on.For example in the printer dedicated to produce the biggest parts as these usually have bigger nozzle sizes anyway.In a commercial sense however it must be considered what the material is worth in terms of normal recycling and the added hours and electricity cost for making your own filament.Unless even the cheapest commercailly available filament still costs much more than what you need to invest to the machines and electricity over the time the man hours are the biggest killer.If you need someone to monitor the filament maker and keep feeding it while making sure the spools wind up correctly then your own spools might end up quite costly.So decide carefully before you invest or use you oven and a mold to make you own recyled plastic bricks for your garden beds and such.

Topic by Downunder35m    |  last reply


How does one make a liquid plastic dip?

It is no longer sold in craft stores except in England and Europe. It was used to make plastic flowers. Dip in a wire form and it makes a minimum surface like a soap bubble.

Question by Kilix    |  last reply


How to grow a crystals with gypsum and other materials?

Dear: Instructables Just to let you know I am limited to materials in my house. I want to grow a crystal with plaster like plaster of Paris but I am running into a few problems. I know that Gypsum or plaster of Paris is already a crystal but it doesn't have the necessary hardness I want. I want It to have a hardness of a minimum of 6 on the Mohs's scale. I also am limited to chemistry knowledge. I've been trying all day to design a crystal with the specifications I want but I've been having trouble trying to draw a Lewis dot diagram for plaster of Paris. I am not that good at drawing Lewis dot diagrams unfortunately. Here are some materials in my house I think I could use to incorporate with the homemade crystals. Acetone Potassium Chloride Sugar Baking Soda Potassium Nitrate and more... Can I have some help please? Thank you. From: Noah

Topic by nschreiber0813    |  last reply


Summer, sun and what to do with faded plastics

A lot of us have machine, bikes or such with plastic parts.And if you are in a country where a UV rating of 10 is a nice spring day already plastics seem to fade away and fail quicker.Over the years I experimented with a lot of things to either prevent this or to fix it.If you ever had your old farm basher parked next to the same but sun protect model you almost start crying LOLColors look like you painted a white haze over it, white plastics turn yelloish and clear plastic, like on the head lamps of your car go dull and yellow.You might know what I mean if have really nice and long summers...So what is the reason for this problem that only seems to affect things in hot and sunny countries?A lot of plastics are actually fully UV resistant and they won't be harmed or changed.Great but they still suffer! ?Not really, it is the softeners, fillers and pigments that suffer most.In the case of clear plastics it is usually polycarbonate mixes and the culprit is the scratch resistant coating applied on it.The hard UV rays promote the oxidisation and break down.So whatever is not resistant to UV will suffer in and mostly on the outside of the plastic.Problem is that UV penetrates quite deep and as a result we often find that UV protecting agents are added.Sometimes as a coating, sometimes as a mix throughout.Older cars often show peeling paint onthe roof or boot lid - the UV protecting in the coating has failed or was just bad.Back in the old days there was whiteners in washing powder, we had white sheets for the beds and other things and leaving them in the sun to dry actually made them whiter and kept them looking fresh - a positive use for UV bleeching ;)In terms of real prevention options are almsot fully limited to keeping the xposure as low and short as possible.There is no clear coating you can apply to keep the UV out that won't affect the looks of the paint job or plastic.And not all of these coating work on all plastics.One option though is to keep the plastic clean and shiny.A highly reflective surface will not scatter the sunlight as much throughout the plastic.Oxidisation is limited as well, especially if you add some polish every now and then.In a lot of cases though this is either no option or way too time consuming for us to keep it up.As a result we start to neglect the routing here and there andover they years the plastic ages faster than what it should.How to fix or restored faded plastic without paying an arm and a leg for specialised products?White is always nice and if you have a washing machine or fridge close enough to a window you might have noticed over the years that the plastic parts now appear a bit darker or slightly yellow, often just on one side of the thing...Old electronics, like Gameboys are doing this too.Red is my other favourite as like black it produces a white haze easy.Either way the solution is pretty much the same: reduce the oxidisation by oxidising it more ;)Whatever is really oxidised in a bad way changed the color instead of just breaking dow the pigments.UV does this...On the other hand hydrogen peroxide bleeches and breaks down stains....As long as parts are small enough it is quite easy to put them in a zip lock bag to submerge them for a few hours or over night in hydrogen peroxide.Otherwise use a suitable container and keep turning and moving the parts around every hour or so until all looks even again.In severe cases and if the plastic permits it you can also add a small amount of diluted hydrochloric acid.Talking diluted! So that means of a low concentration!In most cases though a day or two with just hydrogen peroxide will suffice.Do a little test first though as some plastics might just be caoted and either show no reaction at all or the coating has pigment that break down in the peroxide - I never had this happen to me but I have read reports of it and seen the pics of the results.When it comes to really big parts, like the spoiler on your car or plastic covers on your bike and boat it can be impossible to submerge them even partially.In most cases people try to fix these by polishing them until the faded areas are litterally removed.A much nicer and easier way to cheat is to use a simple car polish that is suitable for plastic parts.Means it should have no warning on it to keep away for plastic parts ;)Wearing proper gloves you can add some hydrogen peroxide to a small amount of the polish.And I mean polish, not the stuff to fix a dull or bad paint - what you would use on a new car...The trick is that the polishing cleans the surface while the peroxide works on the staining and fading.You just don't let the stuff dry after applying it and polish the dry stufff of, you keep going wet until your color comes back ;)After that give it a final polish the normal way with just the polishing compound and no peroxide.Clear plastic...If it is just yor headlamps or other smaller parts for a once off it might make sense to go to a auto shop and buy a head lamp polishing kit.Thing with clear plastics is that only too often they come in shapes or installations that make a full access impossible.Like your head lamps that you can only reach from the front as they are glued into the assembly.Another problem is that they are aslo almost always coated with some protective stuff.If hydrogen peroxide alone does not help here then polishing will always remove some of this coating or even all of it.If the coating happens to be the culprit of the fading and yellowing then you of course get it all nice and shiny by just polishing the coating off - but you also loose all benefits of the coating.Some car models have headlamps where just the coating discolors and once removed the plastic start to crack under the exposure from UV and through all the tiny damages it get when driving around.For things like clear covers over a little display there is the problem as access as you might not be able to remove the window pane, a replacement might be the best option.Hey! Why all the fuzz? I use just oil and it works perfectly!!You can find online videos and full tutorials where people show you that just a bit of some oil and polishing it off with a lint free cloth brings all you faded colors back out again.Don't be fooled just because it works so great!Take a frosted piece of glass and put some oil on it and it becomes clear enough to see through again.Even works with very thin paper...What the oil really deos is to coat all these microscopic imperfections.And with the light now having a very easy way to get through it won't scatter anymore and the fading appears to be gone.Once the oil is gone the plastic looks as bad as before, hence the need to use an oil that dries off.Worst thing is that these oil affect the softeners in the plastic.In some cases this might be benefitial in most it is really bad though.Like any other solvent the oil mixes with these softeners and over time they are removed from the plastic, the more you use oil to keep it shine the more brittle you plastic might get.Once you did that it is next to impossible to remove the oil from within the damaged plastic and only way out i to polish it off after sanding it.The benefit of seemingly protecting the plastic from dirt and water is short lived as well.Some old oil you got on it would just wipe off but with the added oil in the plastic it can now penetrate.And that little black dot becomes hard to get rid of...Last words of wisdom:Check the type of plastic before you decide on anything!Especially when it comes to the black plastic with fibre re-inforcements.Do a tiny spot test in an area that is not so important before going full scale!Trust me, nothing is worse than only realising too late you selecting of choice is actually removing the pigments from the plastic - hint: if your cloth tunrs into the same color as your plastic then something is wrong.Use PPE! Gloves and face shield or at least goggle are a must have when working with hydrogen peroxide or acids.Even at just 3% the peroxide will bleech your skin quickly and long exposure won't be better either.Once you got a drop of peroxide in your eye you will never forget the googles, so just wear them right away please ;)If the fading is due to the breakdown of pigments that give the color like a white haze on red or blue plastic you might still have to polish off that thinnest layer on the surface to remove the fully bleached out layer.This however is really quickly done and after that the smooth surface will last much longer.Work clean!! It is of no use to start before you actually fully cleaned the plastic!

Topic by Downunder35m  


How to fix a defective tumbler lid?

I bought this tumbler a week ago and I just found out that the lid keeps popping up. At first, it was only a problem when it contains warm beverage. Now, it never closes even when empty. I cannot put it in my bag without the risk of spilling liquids on my stuff. Replacing it is not an option because in the first place, I bought it to reduce use of disposables. Add to that that I am a student on a tight budget. I've thought of gluing the lid shut completely, and simply use it like a screw-type lid, but then I'm not sure what type of glue is food-safe yet waterproof. In photos: Lid is flat when closed. After a few seconds, it pops open. The inside of the lid when closed. I suspect the rubber that is supposed to lock it in place is not enough. The lid structure when open. Looking forward to a *lead* to fix this lid ^-^

Question by gelatined    |  last reply


19v to 12v without current drop?

I have laptop charger of 19V 3.42A(65W).i want to step down that 19v to 12v without any decrease in current.i need 12v 3.42+A  what is the simple way? can i use resistors to radius voltage without current drop? can i use LM7812C to get 12v 3.42+A there is ant way to get 12v 5A(65W)

Question by vina1991    |  last reply


how can i drop 1A dc to 500ma dc? Answered

I have an AC-DC power supply with voltages of DC 3 - 4.5 - 6 - 7.5 - 9 - 12V and 1000ma and i want to drop this down to 500ma!

Question by thecookiemonster    |  last reply


K40 Chinese laser conversion to Arduino

After fixing most of the issues on cheap laser cutter I am about to do the next step and install an Arduino board to get rid of the dongle and crappy controller. I also would like to put this in the form of a nice Instructable so others can upgrade their machines as well. But during my research I noticed that several different versions of the controller, laser power supply and control panel exist. If you are interested in upgrading your machine so you can use Inkscape directly and no longer need a dongle and crappy software: Post a pic of your laser power supply (including a clear pic of the connection terminals), a pic of your control panel (both from the outside and the bottom), let me know if you already have safety switches for the lid and water flow. Everything posted here in time will be included in the Instructable if it is different from my machine. Once the Ible is finnished you will get detailed instructions on what you need, how to program the Arduino, get the plugins working in Inkscape and how to do your first real engravings and cuttings on the new setup after calibrating everything. Here is a video showing raster and vector engraving followed by cutting the piece out - what more can I ask for if only spare parts are used? ;) https://youtu.be/GqFTPMBchyQ  

Topic by Downunder35m    |  last reply


Question about Mini CNC Plotter Software

Hi Smart People!Sorry, but I need help! My head is absolutely spinning. And I suspect my question has a simple answer. I built a Mini Plotter using cd/dvd steppers and servo a couple of years ago. But I never quite finished for some reason. So I'm finally getting back to it now, but I have forgotten what software(s) to use. I'm using Inkscape ver. 48.5 w/ Unicorn to save as g-code. That much I've got. I understand that I need to send g-code to a grbl controller? But, I have downloaded so many programs over time, that I have no idea of the sequence anymore. Also, I do not remember gctrl.pde last time I was playing with this project. So my question is: Does anyone have a link for a tutorial for dummies that explains the software chain from Inkscape to finish? I have read so many, and watched so many videos that I have confused myself. Any guidance would be appreciated.

Question by Steve_Lane63    |  last reply


How do you make a digital counter circuit which counts to 10 minutes, it will rings a buzzer and when it continues to 15 minutes, it will rings a buzzer?

I need to make a digital counter circuit which it counts to 15 minutes for my big project in my campus . When the circuit counts to 10 minutes, it will rings a buzzer. Same when it continues to 15 minutes, it will ring a buzzer again. (the circuit is for public speaking, so the speaker knows that he or she already went speak for 10 minutes and 15 minutes). We weren't allowed to use an Arduino, Microcontroller, PLCs, IC NE555, and a 4000 series CMOS IC but we were allowed to use breadboard, flip flop, decoder and 7 segments display. I'm kinda stuck here and I'm thinking it's impossible to make such a thing. Do you have any idea guys?

Question by Najedfahad14    |  last reply


Embedded pictures not working on mobile

I posted an Instructable (https://www.instructables.com/id/Escape-Room-Engineering-Review-Game/) and before I published I checked it over by previewing it. Everything worked, all my pictures showed up, and I thought I was good. After I published I checked my Instructable on my phone and two embedded pictures of a the cryptex in Steps 4 and 5 did not show up. So I got back on my computer, opened it up and the pictures were showing.I unpublished the Instructable, decided to delete those two pictures, reupload them, and try to embed them again. I thought that fixed it because last time I couldn't embed the pictures in anything but the SQUARE3 format and this time it let me embed them as LARGE. Checked the Instructable again on line, everything looked good, and better than before because the pictures showed up the size I wanted. Published again and the two cryptex pictures reverted back to SQUARE3 format and won't show up when I look at it on my phone again. When I go back into the edit page those pictures show up fine and are in the LARGE format. I've never had this happen but I'm somewhat new to embedding images into an Instructable with HTML.Two Questions:1. Does anyone know why this is and happening or someway I can fix this issue?2. The first time I published I entered this Instructable in a contest. When I unpublished it did that remove my contest entry and if so can I reenter the contest somehow?

Topic by TeacherMike    |  last reply


Help: DIY Solar Li-Ion Battery Charger

Heylo, I’m a mechanical engineer by trade but lately I have taken up a fascination in building some fun DIY electronics. I wanted to make a device that could charge 18650’s via solar and then could use those batteries to charge my phone. So I found an instructables tutorial that seemed legit so I bought the following things and tried to wire it all up: Dual 18650 Battery Holder TP4056 Protection Circuit MT3608 5V 2A Boost Circuit Voltmeter Screen So I wanted to kind of figure things out on my own so I wired things up without referencing anything and I’ve done it multiple times but I cannot get anything to work. I have attached photos for reference. Basically, I bought 2 18650 holders and pulled the switch from one and wired it to the other. My thinking was that if I had switches on both the positive and negative terminals, I could switch it between solar charging mode and battery powered mode. It doesn’t work at all and I’m not sure what I did wrong. None of the lights even turn on, on the TP4056 yet alone the LED on 5V 2A circuit. I feel like everything I did was sound. But it’s probably not. Please don’t judge my soldering ability, I know it’s awful. I’m learning and I have awful hand tremors which makes soldering especially difficult. Anyways, thanks for your help in advance. If you need any more photos please let me know.

Topic by Thats Wild    |  last reply


what sealant / glue would i use to repair a life proof case screen that is peeling away?

I went to a hardware store to get recommendation on re-sealing the screen to the lifeproof case but the lady incorrectly suggested a superglue that supposedly was meant to work with plastic and rubber but didn't. As you can see, the superglue burnt the plastic and rubber a bit.  Could someone please recommend a glue or sealant to seal the case again so its waterproof and also is durable so that it doesn't rub off in my pocket. Help please!

Topic by shnookface    |  last reply


Is building a wormhole generator possible?

I have read an interesting patent on a "magnetic vortex wormhole generator"and I think it could work. Before you start discrediting and "debunking" this patent or idea check the patent out. http://www.scribd.com/doc/25112/Magnetic-Votrex-Wormhole-GeneratorPlease write constructive and helpful comments. Also if anyone happens to build one based on the patent and experiments with it successfully, make an instructable; share the information. I just want to know if its possible.

Question    |  last reply


Video Game Ideas Wanted

A couple of friends and I are planning on making our own Video Game. I thought it would be cool to ask others for ideas. Our game is a mixed genre (we are attempting to put as many game types into one as possible, but still keeping it somewhat reasonable) sci fi game based a couple hundred years into the future. Humans have colonized mars, but their is a war between the two planetary alliances. Meanwhile there is an underground organization that controls everything going on in human society. They prepare for the return of the true martian race who left behind some ancient relics which were discovered and kept a secret. The main character is a super soldier created by the underground society. You unite the human race and fight against the aliens. We have story ideas but would like to hear ideas from other people. All suggestions are welcome. Suggestions could include, but are not limited to: Characters Events Weapons Technology Genre types Plot ideas and twists Side missions One other thing is that we were thinking that the aliens could be human based, and be like a sub-species of humans. Yes or No? Any other ideas are welcome. Thanks to all who help.

Topic by DeviateKarma    |  last reply


Peltier Voltage control

I have a broken TEC wine cooler that I am converting into a temp controlled humidor. The MOSFET on the control board blew up so I was able to buy it for $9. I am adding humidity control and I want to log so I am going to control it with a raspberry pi. A Arduino would do but I want to program it in python and will have it host its own site to view data logging or to send failure alert.The wine cooler was rated at 70w, I'm not sure what the Peltier is rated but I am assuming less then that @ 12v. I did some tests with a bench PSU to see what it will draw at various voltages up to 8v (the max my psu goes)

Topic by BintuGomes    |  last reply


Max number of accelerometers

Fairly new to arduino. Using it for a postgrad research experiment.Not sure if my googling is just shitty or if it can’t be done. I’m trying to do measurements of flutter for a flutter suppression system in a wing, and because of this I need to make a high fidelity computer model of the wing using accelerometers. I should be able to get away with six accelerometers and three servos, however from what I can see the ADXL345 only has two independent slave addresses (0x53 and 0x1D) so then I would need at least 3 boards (MEGA2560 currently). In this case I’m worried about bottle necking my control system. So first question is, is two the max number of accelerometers I can use? Second is, are there any better alternatives to arduino for this? Three, if I do need to use multiple boards, is there a tutorial for an easy way I can get them to talk to one another without going through a pc? Otherwise what’s a realistic delay between receiving the accelerometers data, analysing it on a PC and the transmitting a command to the three servos on a different board?

Topic by MarvinGomes    |  last reply


how do i repair a leaking gas tank without welding it?

no one makes the tank for my motorhome anymore and i do not have welding tools.so how do i fix this?

Question by twighahn    |  last reply


Image Keeps Darkening

I'm making an instructable. When I upload a cover photo and save, the cover photo keeps darkening! Anyone know how to fix it?Thanks for reading this!

Topic by zakbobdop    |  last reply


Need help with Original GameBoy DMG

I have an Original GameBoy DMG, that when I turn on with game cartridge loaded , it goes through its trademark symbol then starts flashing with what looks like zeros up and down and across the entire screen, I checked to make sure it was not the game by trying it in another GameBoy I have and it worked fine, any ideas on how to fix, please and thank you.

Question by Smallville1962    |  last reply


Back EMF protection for ignition coil

Hi, i made an ignition coil driver circuit (check image) witch is nothing special cause they are everywhere on the internet but what's really bothering me is the back EMF that would fry the 555IC so if i put a rectifying diode (IN4007) at the VCC pin and the reset pin (like in the circuit image) would it solve the problem? Btw this is my first post so sry for any unclear information, thx.

Question by SND SND    |  last reply


Making smart spy car using Raspberry pi.

Hello guys, here i have new task. lets see who is complete this task.making smart car that can added futures are1) This car can be controlled by voice controlled or a WiFi controlled.2) Obstacle avoided3) installed web cam or pi cam.

Topic by rupesh.waghmale718    |  last reply


how can i turn a magnetron from a microwave into a herf gun? Answered

Hello i am feeling particularily creative at the moment and would like to go down to the beach and pick coconuts from the coconut trees, using a herf ray , in which i would blow up the coconuts with the microwaves being emmited from the magnetron. what i want to know though, as it seems to be missing from every single webpage which mentions the construction of a herf ray using a magnetron is, how exactly would i set up the magnetron so that it would create a directional beam capable of frying a coconut abbout 10-30m off the ground? i have seen this being done by a guy on the beach before, making the coconuts explode using a herf ray, when i asked this person how he was doing it he simply said that he was using a microwave gun made from a microwave also, i have no intension of climbing the trees to get the coconuts

Question by oldmanbeefjerky    |  last reply


Watching the moon without the blurry view?

We put our biggest telescopes on the highest mountians and as far away from civilisation as possible.Reason behind is light pollution and atmospheric distortion.My days of playing with a big telescope in the garden every night are long over, life moves on once you need a job to make a living and something like a family.A while ago I had a look through a friend's telescope at night again when I was asked to give him a hand with the connection to Wifi, computer, printer and so on.Just imagine a big telescope with built in camera and Wifi.Checking the claimed to be astonishingly clear pictures of the moon we took I started to wonder...Being able to get a "close up" so to say of a little crater on the moon is nice.But I missed the clearity.If you take a picture with your phone or camera with perfect setting then you get the best possible picture.Not so much for the moon.Those who ever used a telescopic lens on the camera with some haze or fog will know how things in the atmosphere have certain effects.The moon is basically in a boring grey so BW cameras would be sufficient and also eliminate all the bad side effects of colored imagining chips.Other reasons than our atmosphere that can prevent a clear picture...The earth rotates and so does the moon, sadly this makes tracking hard over such a distance.Constantly changing brightness levels make the right exposure a nightmare, especially if you want to combine images to get a combined one without the shadows.So why not use what we already have to eliminate or compensate most of the issues we have?The hardware required for the tracking of stellar objects and computer control should not be an issue anymore.Once you position is syncronised with the current position of the moon the computer would be able to calculate and track with extreme precision.Using highly sensitive BW cameras might be a short term fix, better would be a chip and lens system only sensitive to the visible wavelengths with the least atmospheric distortions.The last would be to actually use an AI to track every pixel as it is taken and to compare it with previous pixels taken in that same spot to check for brightness matches and wavelenght.A simplyfied version of this is still in use for the restauration of old films from the analog days.The moving film meant that the pictures are not always perfectly in sync in terms of their position for the single images.If digitised like this the result would be a quite blurry film.An algorithm checks for the usual up and down differences and matches the positions so in reference to the selected frame rate it results in the sharpest possible image.For the moon there is always a majority of less distortion giving us the impression of the image we see.The key is have an algorithm that can detect and filter out those frames or if powerful enough pixels with the most distortion.Quite similar to the steady function on your cameras and phones these days, at least for the digital part.Just in reverse so to say.With perfect and smooth tracking a frame by frame collection of the area you want an image of would result in a much clearer and detailed image.A bit like HDR works now.You take a lot of images and combine them to get the best possible details on all light level and all colors.We only need BW though...How would an algorithm an an AI be able to make an image clearer and more detailed?Currently we already compensate for camera movements, brightness levels, focus, colors and much more through the AI of our phones.Where someone with a DSLR or the good old SLR and real film needs to find the perfect setting for a shot in the amount of time the shot is available we just click a button on the screen and the AI does the rest for us.Sure, instead of three or four pictures taken as quickly as your phone can do our MOON-HDR algorithm might need a few thausand pictures to create one good image and several hours to do so....But hey, it is up there every night and day, we can perfectly track it and automate the process over days or weeks if we want to capture a full cycle.If it that easy then certainly the big telescopes on those mountains would make use of it!!Well, they actually do, but for the sole purpose of deep space exploration.The movements of earth and in space and referenced to the possible errors of the hardware...We only need to care about pixels moving in a fixed image...The algorithm in the simple form works on a frame by frame base, the proper one on a direct pixel one.Either way the collected images will create piles where all checks match.More piles means more and more areas to overlay like in a stitching process.More overlays mean more "filter" used to check the original images against.The amount of light hitting the moon is pretty predictable and easy to factor in for an AI.The amount of light loss by the atmosphere at the time the image was taken could be factored in by the means of external atmospheric sensors.In the most basic form a "ping" with a laser onto a satellite on a fixed position between telescope and moon, or close by.The the google AI tries to find more and more links to make more and more reference about our internet use our algorithm collects pixel informations for a fixed position in a digital image.Quite simple once you think about it, isn't it? ;)It is just a matter of time and amount of data being collected.What was already possible in the days of converting analog movies into the digital world can't be too hard to do with an object that we can literally nail to the wall in terms of images....So why isn't anyone doing it already?In therory anyone could just hire some time on a quantum computer or old style super computer and use their own algorithms to sort the images.In reality that would cost you a few millions quickly.Graphics card are already well in use to do other things than bringing an image to a monitor.They used a calculating work horses - the bitcoin mining is a prime example here.Medical and scientific use another.Her it is quite ommon that clusters of powerful graphics cards do nothing than to run simulations.Already a form of AI, although quite simple.There is no huge market for telescopes, let alone big and powerful ones for the sole purpose of watching moon.Why bother, it is up there every night but all the stars and planets up there need to watched first....You will have a hard time finding a manual telescope with a simple way to follow the moon through the night.Watching the andromeda nebula on the other hand is quite easy...Worse still for the cameras.What is out there for use with telescopes or integrated into one is optimised to get the most light out of everything that is quite dim.Even your basic telescope usually has a moon filter already because the thing is so damn bright.Professional BW cameras would need expensive and custom made adapters to fit a telescope's optics.Last but not least is the tracking mechincs that are simply not designed to follow the moon, neither in its movement, nor the speed it is moving.But as said the tracking could be fixed with a custom version designed for watching the moon and a little microcontroller to drive very smoth running motors and gears.Is a fancy smartphone the way out for the images?Not really unless you want to constanly fight to get and keep manual control about the settings for the BW camera on the back.And they are not really designed to be used like that for hours every night.The only way out is size and speed.What would the perfect telscope/camera combination look like?Atmospheric interference means the light is scattered.And ideally that should be the only thing the AI has to worry about later on.Sadly, when we take a picture we need a certain exposure time to capture enough light.This mean mean collect something you compare to a fast moving object.You just cant get a clear image of spinning fan blades easy these days...Shorter exposure times are only possible with enough light.There are two way we use to get enough light for a given exposure time.Add some more light or use a bigger lens.Our standard telescopes are designed for eye pieces for, well, our eyes.Imaginea huge sized 40 megapixel sensor perfectly positioned in a telescope.Using only optics to compensate image distortion and to match the incoming image size to the sensor size.No telescope optics and camera optincs fighting for the right position, just perfectly matched for the purpose of takin images from the moon...If said sensor would be highly sensible most people would cry out and say the moon is too bright - but we want to use every bit of light to lowe our exposure times ;)Imagine a high speed camera only taking BW picture of the moon.At a speed of over 2000 frames per second....Why bother with overcomplicated tracking if you can take millions of images every night.You will only bother about storage and calculating problems after a single night already LOLThe amount of pixels of near identical properties in the same spot would soon be much higher than the amount of blurry pixels with different values.And the AI would still be able to match those blurry ones with frames from other images.But who really wants to see footprints and left over parts on the moon?We have been there, we have seen it...And if go up again we will have live coverage anyway from up close, so there really is no need for anyone to get a clear image of the moon from down here, or is there?

Topic by Downunder35m  


Need HELP with project 30Kva induction heater

Hi. I am Paulo from Portugal. I am trying to build that 30Kva from instructables.com but i need some help. I tryed to contact Mr Wang with no sucess. I have some amateur knowledge about electronics only. I need that machine to melt some exotic steel. It seems you are familiar with that 30kva project. Can someone help me with some answers? I would be grafeful.I already read several times that instructions and to start my first questions are: 1)What for and where connect that 4-position rotary connector? 2) what the exact specs of the main capacitors? About capacitors i found throught ebay the square black box connected on first IGVT is a snubber with specs 20uF and 800V - where to find this one? At ebay only 2nd hand... The other capacitor at the 2nd IGVT can read at scheme specs are 920uF - But how many volts?? - where to buy? And the last one of tank circuit same problem - Can read at scheme is a 3.75uF and also a "high-quality polypropylene or mica giant snubber capacitor" - How many volts?? - Where to buy? I really would apreciate your help if possible. My contact is vfr998@gmail.com . Thanks in advance and best regards. Paulo. Hope to listen from you soon.

Topic by REDMACHINE-A  


What does the Huawei trade ban mean for us?

You might have got in the news ages ago but for those in other countires:The company Huawei together with some of the subdivided companies got involved in the trade war between China and the US.In terms of consequenses for the users we certainly will see that there won't be any new devices getting on the local markets until this disaster got resolved.For existing users or those buying stocked items from before the ban took place the future might be not as good as previously thought.Firmware updates might not be allowed anymore, meaning if Huawei has a usable update for another region that could work it is a manual process that might render the device into a brick.Google already stopped Playstore support for many devices and there won't be any Google licinsed new devies anymore either if they get their will.Gives regional selling a whole new meaning and finally allows the full use of firmware checks and more to keep devices with addded but unlicensed Google services fully out.How did it come to the ban?The claim is that Huawei can already be used by the Chinese government to spy on users or might be to in the future.What gave it a feed for the press was the phones, the ban however is more aimed on backbone infrastructure.Collateral damage so to say.A bit like taking someone without any proof of wrongdoing and to lock him away.Oh, wait that is already a common thing...The funny thing is the same that Huawei now uses in a court claim against the US:Every hardware used for the internet in any way can have security issues.Otherwise we would not need firmware updates to fix security issues.What's the big deal then? Well, that is exactly the point Huawei is trying to make in court now.The problem behind the band and now issues worldwide is however realted to something we might not really consider at a first glance: The new 5G network for our mobile phones and other mobile devices.Once some "hackers" exposed and excessive list of security flaws in the 5G network two things became evident way too quickly:A) The same agencies that signed up on the security of the network got exposed for already impementing them into their surveillance systems.B) The securtiy flaws are so severe that anyone with access to the backbone infrastructure could basically check whatever happens on any part of the network, down to the user level and possible device control through remote services.The first is not a deal breaker as the agencies got exposed for abusing the rights of people since they exist.The second means it is no big deal to create patches for the flaws that can be implemented through firmware updates.And that is exactly the concerns of those spying on us (legally they claim).To implement the fixes you need to provide the information on the flaws and the exact way to fix them - which means you provide the information required to get acess like before even with the updates rolled out.Huawei provides everything from end user devices (phones and such), over routers and modems to the hardware required by your ISP or those in charge of the worldwide backbone infrastructure.With the ban it is now possible to get the 5G network happening with "Made in the USA" hardware only.Or, of course hardware from "trusted" companies outside the US.Brings nice and decent boost for the local harware manufactures while hiding the fact that the 5G network in the current form is more like a Swiss chesse - fully holes in terms of security.There are now claims however that say those agencies that signed up on the security "overlooked" the security flaws with the intention of having a future option against China in the trade war.Too bad the security flaws were not kep secret by those "hacker" paid to confirm the safety, instead they made an almost public event to present them.Otherwise the whole thing would have gone totally unnoticed by the world.And if such a move ever showed one thing than it is loyalty and only those countries with strong ties to the US jumped onto the ban while other either say they don't see concerns or simply wait until the concerns are proven to be real before replacing all the expensive gear with US products.If you followed the trade war a bit you realised it already thing with global consequences.Entire supply chains struggle or collapse already.Jobs are lost, economies suffer.And what was already a problem for countries outside Chinese and USA territories is now affecting the big guys as well.The world depends on fair trade.This fair bit is now devided by two countries deciding on what the rest of the world has to pay.What started with the refusal to take our rubbish was played out like a fight between two rival sibling below school age.Things are said and tossed around with no care about what happens as a result.Only problem is the toys are not stying in a kids room, the toys are things in other countries.The scratches are not a kids skin, they are in the hip pockets of everyone.Except for a few things both countries could do fine without each other that is what trading is for.But both countries want full control about everything with no care about how this affects other countries and people in the world.Prices are going up for everything as result.Will there be a winner, will there be an end, how might it end?There is only one winner and this winner is already clear, or make that two: Big companies and banks.Only those with a supply chain affected by the trade war will struggle to compensate and adjust to the changes.We just pay a higher price and have to accept it.Unless both sides give in and act like adults instead of toddlers the only possible end is once one side has fully control again.The most likely end would be a great devide between the US and China and a s result China getting an even stronger focus on being better than the rest of the world without involving it.Trillions of Dollars are wasted every year just because those two have to make copies of everything the other onew does wihtout ever really working together to more than half the costs.Not mention the money saved on no longer needing to spy on each other.Just take the moon, the USA needs to get back up there fast, China has fixed plans and India is not far behind either.Russia is stitting back and doing a bit here and there for everyone to be included without wasting too much money.If you check the territories in Antartica you will notice there is not that much Chinese presence.That bit of our world is appearntly only for peaceful exploration, despite the ever present military.Now what about the moon again ?China already managed several times to sent probes not only to the moon but also onto the moon - without any of it being detected by the US.Only once China presented images and videos it becae evident that their space program is much further ahead than previously thought.Pretending to only help the poor civilians aorund the south pole is a thing you might get away with.Not so much however when it comes to territories on the moon.If you can estabilsh a scientific base on the moon or estabilsh moning operations than how hard would it be to do the same with a military installation?And from up there even throwing rocks down to earth would do enough damage if the rocks are big enough...Nw, if you can't trsut a a space travelling country here on earth: How can you trust them to behave on the moon where really no one can go have a quick check on things?It is not like anyone would go for a quick drive to next outpost if it means risking your life every meter of the way.The consequences of this useless trade war are not only globally but start to affect the lifes everyone in the modern world.And did anyone ever consider that the atmospheric distortions are a problem for a telescope when watching the moon but not so much the other way around?Using the same digital telescope a pixel on the moon circles about 50 meters.Thanks to the long distance from out atmosphere to the moon.On the other hand the same pixel on earth, if watched from the moon, would only move around a few cm at the worst of times!

Topic by Downunder35m  


how can I embed images in an instructable ?

I have read a thread detailing image embedding using https://www.instructables.com/id/How-to-Embed-Photos-in-an-Instructable/ However, I can't make this work : I upload the images. I embed them using the img html tag. The image is correctly shown in the edition window. When I press "preview", the images are no longer shown. I have tried different sizes and formats, some have briefly worked (= were shown in the preview window), but all ended up disappearing at one point or another.

Question by IverB    |  last reply


Relay with small in size

I have a relay with an Outline Dimensions:(15.5x10.5x11.8)mm 5V,3A--> Switching voltage 230VACDatasheet is given above..could you suggest the similar capacity with small in size (not a solid state relay) relay ??i was search website like MOUSER,LCSC .didn't find any suitable one.

Topic by shavanwe0    |  last reply


Three Dual Voltage Output Circuit required

I have an 30v 0 30v 10 amp with 12v 0 12v 1.5 amp AC Volt Output Transformer. I required +24v 0 -24v and +12v 0 -12v and 05v DC Voltage, How can i taken these three output using this transformer. I am using a audio board so its required less than 1 amp output capacity only, But in transformer capacity was 10 amp. I want to to know excess amp will affect the board or Not ?Kindly sent the idea and Circuit diagramThanking You.

Question by ragavan123  


Why or why not does .9 repeating equal 1?

I already posted this as a regular question, but someone told me to make it as a burning question, so here it is: HI! I am wondering if .999...=1? I mean if 1/3=.333 and 1/3+1/3+1/3=3/3 and 3/3=1. So wouldn't .333...+.333...+.333...=1? But it actually equals .999... not 1. I googled this question and I got many different answers ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For example...(someone wrote): I'm not really into math, but a friend brought something up to me today that really seemed very strange. (For the duration of this post, .999 will mean .9 repeating unless otherwise specified- just for the sake of ease) .999=x 10x=9.999 10x - x = 9x 9x=9 1x=1. .999 = 1. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Someone else wrote: Numbers are fake. They are a manifestation of our minds to describe something, similar to words. Just because we say "red" doesn't mean something is red. what is red? Languages and math are very similar. Math is universal...at least for our planet though. .999~ does not = 1. But what .999~ repeating represents, does in fact equal what 1 represents. No-one will ever be able to comprehend infinity, os its time to stop trying. Think of space and the universe. IT IS GROWING. how can it continue to grow with no stop? what is there to contain it? WE need something to contain it in order for us to understand it. We need a stopping point, but there is none. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Another person wrote: In your proof that .333...*3=.999... you forgot to include the fact that .3333... is NOT 1/3. 1/3 if not a number that can be turned into a decimal in any way. I thought someone might like to know this fact. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ And the last person wrote: Just a pedantic point the equation for differentiation is given by lim x->0 [f(x+h)-f(x)]/h, it has the minus sign. It is after all just telling you the slope and is no different really from doing simple trig using the tan function. Here you just take a really small triangle. As to the 0.99~ thing, this is really just writing the supremum (spelling might be off) of the numbers less than 1. Just think of it as taking the smallest number 'n-word' than 0 away from 1. They are not identical for if they were we would not have a continuous number line, but rather a dashed one with lots of wholes in it. I could simply argue that 0.99~8 is just as close to 0.99~9 as 0.99~ is to 1. For those who really want to understand go and look up supremum numbers and the axioms of the real number line. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ So who is correct? Do you agree that .999...=1? Or .999... does not equal 1?

Topic by Pizzapie500    |  last reply


Using two 12V batteries in series with both a 12V and 24V output

I have a tornado shelterthat I have wired for both 120V AC and 12V DC. All of the lighting is via 12V DC while the AC is used for recharging the batteries and running a 1500 VA UPS system that powers a small TV and radio. The UPS system normally uses two small 12V SLA batteries in series. To increase the run time of the UPS I want to use auto batteries instead of the small SLA batteries normally used. In order to cut down on the cost of batteries I want to use two auto batteries, one 100AH battery used for the main lighting and a 50AH battery in series with the 100AH battery to provide the 24 volts for the UPS system. The UPS system will only use the two batteries when the AC is out which is normally rare. Do you see any problems with this setup providing I install a diode in the UPS battery feed to prevent the UPS from recharging the batteries and use separate smart chargers connected to each individual battery? I feel I have overlooked something but I can't seem to put my finger on it.

Question by Uncorkvet    |  last reply


Is the KNEX gun community dead?

So there has not been a post in the KNEX forum section for weeks about KNEX guns and It is getting so slow and dead around here that I could not stand it any more so I thought I would post a topic to see what others think. Are any of you working on stuff? I know some KNEX gunners have moved to YouTube but there is still very little content also a lot of people have left I know years ago everybody was saying that the community was dead but there was a nice jump in activity in the last year or so but It seams that stuff is dead as meat around here know. I found this community to be are very welcoming and fun place on the internet and I would hate to see it dead for good. Is there anybody that has plans of posting again? I just want to know how things are going has everybody lost interest or just grown out of this hobby? I hope that we can come back to life but I don't know will 2015 go down as the year the KNEX gun community died? Hope all is well with all you KNEXers! 

Topic by sonic broom    |  last reply


Cover image darkening Answered

Hello,I recently made an instructable and when i saved it, it always darkened the cover image so it made it really hard to see. I tried over and over again but every time and even with different pictures, after generating the image, it would make it really dark.I'm wondering if there is a way to fix this? I hope it does not affect my instructable as it is entered in a contest. I took a screenshot to show the difference, i might not look bad but on the contest its really dark.Contest linkInstructable Link

Question by Perfect DIY    |  last reply


how to reduce current with out affecting the voltage?

I have a 12V transformer and i want to hook it up to my NST but it has a current rating of 8A but my transformer is to powerful and the lowest voltage is 12V.

Question by Jimmy Proton    |  last reply


FPGA and video projector

Hi I want to use FPGA as source for a Video projector.Is it possible? And if so,Should I code it as when I want to connect it to VGA monitor?

Question by Saeid_haghighipour    |  last reply