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Model RR, LEDs on variable ac input voltage Answered

Led's for ac powered model railroading, to replace incandescent bulbs.  Voltage to track varies from 5 to 17 volts AC.  Leds will light up, but what is it doing to them. They do not pop like a flash bulb at top voltage. I've rectified some to dc voltage for lights in cars, the variable voltage seems to power them. Ideally a circuit that put out a constant 3.2 DC volts, with a variable 5 to 17 volt AC input.  Or maybe would a constant 3.2 volt AC out would function? I found that with HO DCC control, a white led with a 1k resistor will function, have not ran them for more than few hours though. Prewired rectified leds go for around $3.00  each, 5 passenger cars, 2 bulbs each, gets pricey with 4 sets of cars. Surly someone has gone through this.

Question by 31cssinc    |  last reply

Why doesn't pdf download work any more? Answered

I've been a premium member for several years and have downloaded many pdf files.  The last week I get an error message- file does not begin with '%pdf-'. Rideable-Segway….pdf I've tried at lease 5 different files and get the same results.  Please help Don't know what category or channel is useful for this question, will just pick 1

Question by wmrhoward    |  last reply

I need to repeat radio frequency in the 402MHz range.

I need to repeat radio frequency in the 402MHz range.  How do you build a RF repeater? I need to extend the range of a CGM (Continuous Glucose Monitor). It uses the MICS protocol.  Can you adapt an existing device?

Topic by arourke1    |  last reply

Would you like an assembling package for your DIY project?

I am thinking about doing a project to build a set of parts that can be assembled together to build a package for any(most) DIY project. Most of time, the PCB is easy to make but the package is much harder(expensive) to make or find. I want to build a set of parts, so anyone can easily build a package for his/her own diy device. I will try to make them flexible, looking good(or fun) on most devices. Would you be interested in something like this? Please let me know, so I know I am building something someone may want. 

Topic by zpfxellose    |  last reply

Can someone hack into your car?

I have found a few interesting videos of vehicles hacked and controlled by other than the driver. Many things in the car can be controlled like the gas pedal and brakes. After the tragic death of journalist Michael Hastings more investigations are being done on the subject.

Topic by blkhawk    |  last reply

Year-to-Data, March 2014

Tl;dr: Check out this pie chart that shows the distribution of projects published in 2014 by category. The outer ring shows the channel within the category that had the highest volume of entries, along with the year to date project count. Do you ever wonder how the projects on Instructables are distributed across categories? I did, too. In a tenuous-at-best connection to the Pi Day Pie Contest, we made a pie chart showing where all the newly-published projects have been categorized since the start of 2014. That outside ring shows the most popular channels within the category, along with a project count for each. Some quick observations: (1) There isn’t as much food as I would have thought. It seems like people are posting food ALL THE TIME, but apparently the overall project volume is coming in via other channels. I guess we’re just getting a lot of good food entries that are being featured more often. The quality of authors’ food photography is getting very good, and the featuring team may be featuring projects under the influence of hunger. (2) Contests drive some (but not all) project builds. Since the start of the year, we’ve run paracord, organization, electronics, and crafting contests. And, wouldn’t you know it, those are the channels receiving the bulk of new projects. Even without a special contest, the Toys channel received an outsized number of projects, so we’ll see what happens later this year when we run a few contests around toys. (Pro-tip: Start stockpiling LEGO and KNEX pieces.) (3) Technology and Living make up just over half of the site’s new content. Sure, the robot has a strong preference for electronics projects, but we’re seeing a lot of great craft projects coming in as well. Either way, an army of hot-tool wielding* makers are creating some really cool stuff. (4) This community may be a little paranoid, but we’re prepared. Paracord and survival projects account for almost all of the outdoor projects we’ve seen so far this year. If I’m stuck in a rural farmhouse surrounded by zombies, I want some of you all right there with me. If you’re worried about the imminent collapse of civilization and are concerned that Instructables won't be around to help with the power out, you can buy a book of some of our best homesteading projects. You’ll be sitting pretty with a chicken coop and some rain barrels while everyone else gets punched over a can of soup. (Don't get punched over a can of soup.) (5) Did you notice anything interesting? Sound off in the comments. I've got some 3 month pro memberships to give away to insightful commenters. :D *or hot, tool-wielding authors.

Topic by wilgubeast    |  last reply

What adhesive to use for gluing zip lock bag material to fabric?

I have a project in mind which I want to line with a food safe material. After some consideration It boiled down to just using pieces cut from a zip lock bag and cotton material. I'm going to hem the 2 materials together but don't want the zip lock material slouching and separating from the cotton material in the middle. If I used a spray adhesive for fabric to adhere the zip lock material flat to the cotton will the adhesive show through the zip lock liner? I want it to look clear so cotton material shows through the plastic like laminated cotton but don't want to use that material. Any ideas or product suggestions? Thanks.

Question by lexpres61    |  last reply

I am not able to enter Full Spectrum laser contest

I am not able to enter my instructable in the full spectrum laser contest. Can  you please help me out. I posted it on Mar 18, 2014 and it is within the dates they have mentioned.The following message appears.

Topic by BakeitUp    |  last reply

Hacking Flatbed Scanner Components

I am currently working on a project which was going to use a scanner to acquire an image. The scanner is/was an HP 6200C. When I was trying to modify the scanner I accidentally broke the lamp, but was then excited to discover [what I believe is] a linear photodiode array which functioned as the detector. (I also found some cool mirrors and a focusing lens inside.) This photodiode array could be very useful to my project.  This scanner interfaces with my computer through USB, and refused to work after I unplugged the lamp. I figure a resistor may trick the circuitry into thinking the lamp is still attached, but I no longer require the moving parts of the scanner at all; I only want the photodiode array and a way for it to interface with the computer, preferably giving either a "single line" type image or a "single really thick line" type image. (Basically I just need intensity and location of signal. If the received data is a full image, I can reduce it to what I need.) Does anyone have any experience or suggestions for me? I have uploaded a few pictures of the relevant circuitry and can add more upon request. Update: After further research, I've determined that it is not a photodiode array but a linear CCD.

Topic by rogers236    |  last reply

How can i make lcd display to show 1 when i press a momentary button 108 times and 2 when i press it another 108 times? Answered

Lcd display is a 2 digit display and i want it to go to 99. it should go up  by 1 every 108 button presses. any help is appreciated. forgot to mention i am using arduino so i needed help on code. thanks in advance

Question by sarju7    |  last reply

Brushless motor not running,help needed..!!!

I have Turnigy 2836, 2350Kv outrunner connected to Hobbyking 40A SBEC ,Rhino 1550mAh 3S 20c Lipoly Battery and a Hobbyking servo tester to control the motor .when i try to start it makes two beep sound, vibrates and turns was perfectly running last time i checked .which components' fault is this??? and how to check lipoly's voltage and current?can i use normal multimeter? thanks for the suggestion....

Question by ferraririder123    |  last reply

Motor controller circuit with inverting switch (automatic cover driver)

Hi!  I need some help on a circuit i need to make, for a tonnau cover open and close The basic principle of the circuit is i hit a switch, the switch tuns on a relay, the relay starts the motor, cover opens and automatically stops when hiting a microswitch on the tonnau cover that indicates the open state (of the cover) and keeps it that way until i hit the switch again. Then when i push the switch again, the cover should close and on the fully closed position hit a microswitch that resets the circuit or enables the first part again... I have a few ideas, but nothing concrete and i can't find any simmilar circuits :(

Question by Hrenowsky    |  last reply

How to laser cut 90 degree interlocking gears? Answered

I am working on a project that involves laser cutting wooden gears, and I would like some of these gears to be at 90 degrees to each other. Ideally, a beveled gear would be the best for this, but I doubt I could make one with a laser (I could possibly modify this method, or make one with interlocking parts but...) So to do that do I need to make a special type of gear, or could I just use this and mount them at 90 degrees?

Question by astroboy907    |  last reply

How can I make Plants vs Zombies to have a license for more than an hour?

How and where to download the game Plants vs Zombies  licensed, game found only demo.

Topic by pastore michel    |  last reply

Where you can download the game minecraft?

Where you can download the game minecraft full edition?

Topic by sara23    |  last reply

How to generate a beep sound in a watch ? Answered

I'm working on an electronic design project : Smart Watch  this watch worn  by clients suffering  from early stages of Alzheimer disease  will play a role so that it guides the patient back to his/her house . We pre-defined a distance boundary that the client will not exceed (speedometer). I want to know if there is a device (sensor) that should be integrated in the watch  so that it generates or creates beep sound (or vibrations) once the client crossed or approaches the Limit distance boundary ( something similar to the beep sound in the car system when it approaches an obstacle ). And , if it is possible ,any ideas or hints on how to implement it on the watch ? Thank you in advance , and if you need more information please let me know :)

Question by ClearVision    |  last reply

Download is still not working. Even with Mozilla, I get a 404?

I am still getting no downloads.  With Mozilla Firefox I get Error 404.  I am a member in good standing. What is up? Peter E. Hughes

Question by pehughes    |  last reply

Building custom tiny stereo to output sound from two different sources

Hello there, I'd want to build a tiny custom stereo, small enough to be mounted on a forearm. It has to receive input from two different sources: my smartphone (should act as a simple mp3 player) and a head mounted microphone. As I'm not into electronics really, I would use some help. I've read this instructable as reference: I'm not pretty sure about what kind of speakers I should use and what exact components I should need. I'd want to use two speakers and I don't really care about stereo sound, actually I would prefer mono sound. Maybe I could use one speaker for the phone output and the other one for the microphone output. I'd also like to put the amplifier distant from the speakers, since the forearm mount should be as slim as possible, so I'd put it in the back trousers pocket, if I manage to make it small enough. As you see I'm kind of confused, I have ideas, but not knowledge. Have you got any guide or whatever I could use? Thank you for your help!

Question by gabry207    |  last reply

Singing Book Cover

I want to build a book cover that plays a song i chose when pressed the button. I wrote a book about our good times with my girlfriend. I have it with hard cover. I wanna add a button on it that will play the song. But I'm so new to these things and have no idea how to do it. It have to be a little slim so to keep the esthetics. Anyone can help me with that ?

Topic by Morfildor    |  last reply

Why not get high voltage by boosting 300V to say 2KV ?

Hi, I plan to build High Voltage of 4KV. The output current is very low (say 100uA). I intend to use this as focus voltage in a CRT application. Hence, I am exploring the ways to do so. I have seen people building high voltage (8-20KV) using transformer followed by voltage multipliers. Now a days, MOSFETs are available which can withstand voltage upto 4.5KV. So it should be possible to create boost converter which could boost 300V to 2KV. Then one can further boost the voltage using voltage multipliers. The input voltage of 300V is achieved by rectifying the line voltage of 220V/50Hz. Visiting internet, I do not see anybody doing so. Hence I wonder what could be wrong in doing something of this kind. Could somebody elaborate ? Regards, Hardeep

Question by hardeeps    |  last reply

Connecting External Plastic Water Storage Tanks

I would like to ask a couple of questions about joining two external water storage tanks. The tanks have a capacity of 1,500 litres each and my plan is  to connect the two tanks with one inch pvc piping. The domestic water inlet is low pressure (and that's being kind!) but tank A is usually full. My question is will there be enough pressure in tank A to feed water through the one inch pvc piping and into tank B without using a pump? If you consider the water pressure to be high enough to transfer water from one tank to the next, how many tanks could be connected in this way (I am thinking of four tanks)? The outlet from the water pump feeds 9 washing machines in a small launderette. Sorry about the awful drawing. Thanks for any advice in advance.

Topic by apex2000    |  last reply


Why is it that when I go to select a single post/project, that, as soon as I select "favorite" it tends to say that everything by that author is my favorite?

Question by njc121983    |  last reply

Need Help with Arduino code for gesture controlled robotic arm?

Hello! I'm doing a project on gesture controlled robotic arm. I'm using MATLAB for gesture recognition, and have interfaced it with the arduino board. When a gesture, say up, is recognised, a pin is made high. How do I go about programming the arduino to make the arm move up (i.e control the servo motor in one direction) as long as I show up, and make it move back down when I show the gesture for down (make the servo motor rotate in the opposite direction for as long as the gesture is shown)?  I only know how to do this for analog inputs, not digital ones. I'm sorry if this is a silly question, I'm new to Arduino. Thank you for your time!

Question by AnjanaRao    |  last reply

CHALLENGE: Dirty Video Mixer with Sound Sensor!

Hey guys I have a challenge for you all but forewarning I am a bit of a novice with Arduino and electronics in general. I want to adapt Karl Klomp's Dirty & Cheap video mixer (schematic attached) into something a bit more responsive. The original video mixer is essentially just two RCA inputs fed into a potentiometer and then a combined output is produced as a mix of the two original video sources. I want to swap the potentiometer for a sound sensor (image attached) to allow for the mix of the video output to be governed by the volume of the mixer's surroundings. If anyone could please help me that would be great!!! (Even my lecturers are stumped) Thanks in advance guys! Ryan

Topic by rachten    |  last reply

How can I sequence several small motors. Answered

Wife approved Home Theater ​I plan to build raised panel cabinets that also hide home theater speakers and 60" screen. Open display/bookshelves sit between the speaker garage and the 60" screen. The raised panel (I'll make with my 5hp shaper) covering the speaker will roll over the display cabinet allowing the speakers to move out into the room on motorized platforms. Then, the speakers will rotate on a motorized turntable  to the desired position. Next, the two panels covering the screen will move under the speaker panels and also cover the display cabinet plus a little of the garage space. I want this to all be initiated with the push of a button. The motors will all be sequential in the above order. First, the speaker panel can roll until it hits a button, next, the speaker platform movement could be controlled by motor revolutions as in a stepmotor and would stop the platform at the right spot. When this action is complete, the speaker rotation could also use a step motor count. Next, the two screen panels will roll under the speaker panels until they hit a final stop button. I will need a central controller to manage the sequence order. I am familiar with Fishertechnik robotics controllers but I'm hoping that someone here can give me some suggestions to make this work. Thanks for reading. Chuck

Question by oneartist    |  last reply

Contest Moderation Ideas

Hi guys. I want to talk about contests. Contests have an age limit that prevents I'bles that are over a month old from entering. The age limit is there because of a valid issue, but in my opinion, it's not our best solution. If there were no limits at all, people would try to enter all of their Instructables into every contest, which is no good. The one month age limit encourages people to create new Instructables for specific contests. Which is great. It's what we want. The contests are here to encourage us to make new I'bles and grow the site. That's not always what happens though. It's tempting to try to enter every new Instructable into every current contest. Most of the time this tactic doesn't work, but sometimes it works better than it should. Actually, it's seeming to me like the first potential contest entry always seems to get accepted, no matter how irrelevant it is. What's up with that? Maybe we need a new set of guidelines to follow when deciding whether an Instructable should enter a contest. Something like this: 1.  Instructables can only enter, say, 7 contests. 2.  Instructables cannot win more than one contest. 3.  Instructables cannot try to enter more than, say, 15 contests. This way a user must consider whether a certain contest is really the right contest to enter. Contests become a limited resource; something to choose between wisely. The age limit may encourage the creation of many new I'bles, but the alternative system I have proposed gives people the incentive to make wiser choices, which in turn helps moderate the contests. While the number of new Instructables might drop a little, this alternative system could keep our wonderful website in better order. What about you guys? Do you have any ideas for better contest moderation systems? Do you agree or disagree with my idea? It's just an idea, but maybe it'll spark a discussion that could lead to some good.

Topic by Sadi789    |  last reply

Mind Control RC Car

Hi my names Paul Im doing a project on building a Mind Control RC Car using the EEG Emotiv Headset. I was planning connect the headset to the laptop and use an arduino to connect up to an interface board(im not too sure) which connects to the remote joystick.  I was wondering if anyone has done this project before and it would be so awesome to get any tips or instructions of any sort.  Thanks please let me know

Topic by paulyshin  

Using an optocoupler ? Answered

Hi i got a few opocouplers , MOC3023 I read the data sheet and it says that the input voltage for the control side is about 1.2v I want to use it with an arduino uno , any idea how to reduce the voltage from 5v to 1.2v? here is the link for the data sheet Thank you in advance Aki

Question by akinich    |  last reply

Ideas for my black walnut table?

I cut down 2 huge black walnut trees in my backyard and I have decided to make some tables but I need some tips and ideas for the table.. The thing stumping me the most (haha) is how should I make the legs for a table that small probably 2 feet in across?

Question by Don,t try this at home    |  last reply

how to make a moped out of a mountain bike?

Where can i find a good cheap kit? what can i use for a engine? 

Question by mrknowit    |  last reply

Need Help With Quadcopter Idea

Hello, I’m a senior in high school and I will be participating in a senior project in about 2 months from now. i had decided that I wanted to build a quadcopter thinking that it would give me good experience with electronics and programming. I was planning on using a simple Arduino to control the quad but now that I think of it, it might be much harder than I thought. I know a fair bit of java, have some experience with other microcontrollers, but very little with Arduinos. My initial thought was to buy all of the parts for a quad and program the whole thing myself with a few extra electronics like gyros and accelerometers, there seems to be little info about people who have programmed quads using Arduinos which doesn’t help. Do you think that programing the whole thing will serve to be way too difficult for me (will have a little help from some programing teachers) or should I just go for a complete flight controller instead. There needs to be some work that I have to do for 5 hours a day for 3 weeks, is there anything where the programing is simplified but requires me to do some work. Is there any flight controllers that I can program on top of like for example add IR sensors for obstacle avoidance. With a flight control board, things will be too easy, the only thing I can think of is to maybe create a CAD frame and 3d print it or something. What I’m really asking is, is there a simpler way to do this while keeping me occupied at work? Or even any suggestions on things I can do? Thanks,

Topic by dodomang777    |  last reply

peltier device air con

Hey guys I am working on a project, my first, and am wondering if any one is willing to offer advice. the simple setup uses a swamp cooler to blow cold air over a radiator. the radiator cools down water that is connected to a peltier.if my theory is half accurate (which at best it is) I should be able to make the peltier quite a few degrees below the ambient temperature.

Topic by plucas1    |  last reply

BEC and Semi Conductors

Hey everyone, I don't know if this is right, but today I came to the conclusion that everything in the universe is a conductor or a semi conductor. Is this right? I was thinking if you were to turn something into BEC (Bose-Einstein condensate), (which I know is at the moment impossible), the electrons/current should be able to move through the substance without any resistance. With this being said, couldn't any thing and everything become a perfect conductor if reaching absolute zero is possible? This is just a thought, but I am very interested to find out for a science class I'm taking.                                                                             Thanks for your time KayakKid.

Topic by Kayak Kid    |  last reply

Help with Company Name

I have a Pic searched what i could any one know its an LCD 20 pin cant find pinouts

Question by MACKattacksnipe    |  last reply

How can replicate the functionality of this bike rack cradle?

I have a bike rack with rubber cradles that have dried out. I'm annoyed because the cradles are no longer available and every rack manufacturer seems to make cradles to fit a different bar diameter. In my case it's 1.125". Current racks on the market are either 1" or 1.25". Any ideas on how to replicate the functionality of this cradle? I need to make 8 of them. It needs to be soft enough not to scratch the paint finish on a bicycle.

Question by goodgnus    |  last reply

fav sports

Hey guys list ur fav sport right here!! mine is..........FOOTBALL!!!

Topic by kylekosan23    |  last reply

Assembling a Development Team (VC funding in progress)

I will keep this short and sweet. I am in the process of getting VC funding for my company/video game. I am taking emails on all parts of the development cycle. I will be using the Unity Gaming Engine for proof of concept and possible the complete game. Being that funding has not be secured yet this will be "pro bono". Please note that once funding is approved you will be offered a full-time position.  You will NOT be asked to do any work without knowing you will be offered a full time position. A non disclosure agreement has already been drafted and will have to be signed before any discussion about the game can take place. If you are interested please contact me at Again I am looking at all parts of the development process. If you do not know the Unity Engine that does NOT disqualify you as there are many parts to the video game developement process that exist outside of Unity. 

Topic by danders2    |  last reply

Lets discuss our project interest here

Hello everyone, share your thoughts & ideas here..

Topic by ALP Electronic Innovation    |  last reply

Extremely Slow Download for PDF documents

Hello All,  I am having trouble when trying to access PDF documents with my pro membership.  I am trying to download the "How to make a custom library part in Eagle Cad-too.pdf" and I am getting about 700Bytes/Second download speeds (that is 700 Bytes, Not Kbytes or Mbytes.  I haven't had one finish to be able to determine if the file does eventually come through intact or not.  Is there something I am doing wrong?  I don't have speed issues on any other site.  Most of the time I average 2-3Mbytes/second downloads

Topic by Damageinc333    |  last reply

Why can't I publish my project?

I'm desperately trying to publish my video but it does not publish. :( I don't know what it is the problem , can someone help me please? Here's the link : Thank you

Question by DELETED_gorgeousvoyager    |  last reply

Pop Rivet reamaining Stem removal on its head

How do i remove the remaining stem on this pop rivet? please help guys. highly appreciated. thanks so much

Question by avanteguarde    |  last reply

Robot Shirt Hall of Fame!

Hey Guys! One of my favorite things to see while I'm pouring over projects on the site is images of makers wearing their Instructables T-shirt while they are making stuff! So today, I am reaching out to YOU, YES YOU!!! to post your Instructables Robot -T-shirt-Selfie to this forum post. I would like to make a mosaic of all you lovely makers out there reppin' the robot. (and possibly put it on the homepage rotator behind the "let's make_______") The Instructables Community is totally amazing, and I can't wait to see you in your Robot Shirt. xo Aud

Topic by audreyobscura    |  last reply

EVA thickness for solar cells? Answered

Does it matter what thickness I use to encapsulate my solar cells?  I have gone with a 0.23 mm sheet and the sales rep is trying to get me to buy the 0.4mm sheet which is more expensive saying that the lighting conditions will be better off than on the thinner eva. I don't really believe that the thicker sheet would allow the solar cell / panel to increase the power generation but i have no experience in this nor could i find a forum that discusses this topic.  What have you guys found? does the eva thickness matter? Thanks!

Question by Poloman    |  last reply

How can you make your computer dual screen (as in two monitors)?

It would be great if some one sent me a link or a vid on how its done or explain it below

Question by kevincity228    |  last reply

One Front/Thumbnail Image Not Displaying

Hello, I have an odd problem.  On one of my submissions, the front/thumbnail image stopped displaying.  It was OK some time ago.  I have tried deleting the old image, re-uploading it and re-selecting it without success.  The image is perfectly visible in the "edit" page and image library - as well as on a computer outside of  The problem can be seen when searching thus:;=adeldor+acorn I don't know beforehand if it'll show here, but I'll attempt to attach the problem image to this message. Any advice appreciated! Cheers.

Topic by Adeldor    |  last reply

Incorrect Thumbnail image

In my Quik Shawl (Chop) Stick the thumbnail image is incorrect.  I deleted that image from my library on Jan 5, 2014; before publishing the instructable today.  I had made many versions since I deleted the current Thumbnail image.  Yet it is appearing as the thumbnail.  I do not want that image as the first image seen.  The cover image should be the Thumbnail image. I am using Window XP. Firefox ESR 24.2.0 I just remembered during the editing of the instructable I clicked the Try The New Editor! button.  After I finished making edits and closed the instructable then went back in for edits I was no longer using the new editor.  Thank you in-advance for your help.

Topic by ezman    |  last reply

robot control via internet and shield gsm

Hello from tunisia could you please help me a little bit about my final project fo study i wanna control a robot using a gsm/gprs shield arduino and a arduino mega 2560 card. i wanna make a webpage that control the robot via internet using the sim card inside the robt. do you have anyidea how to do it . is it possible that the robot send pictures capture of the camera ov 7670 cmos  to the web page . thank you

Topic by joujou_tunisien    |  last reply