Picture of Mini-Multitouch Interface
This Instructable shows you how to create a mini-multitouch interface out of simple parts you can order online or purchase at a typical construction/hardware store.

Multitouch interfaces are surfaces that can register multiple 'touch points' at the same time,
meaning users can use natural hand movements to manipulate digital objects. Most multitouch systems also project the screen image onto the touch surface, making interaction more intuitive.

Since big multitouch systems are expensive to build, this instructable teaches you how to build a simpler and smaller multitouch system for $50-150 using easy to find parts. A Mini-Multitouch.

Mini-Multitouch works by the same principles as larger systems, and is handy for all sorts of hack-ish or art-ish uses (think fingerpainting, music-by-touch, or other gesture-based interactions).

This Instructable is being submitted as part of the "Win a Laser Cutter" contest on behalf of Make:Philly, in the hope that we might be able to kick off the creation of our new community workspace with the introduction of a shiny new laser cutter :)


Difficulty: Intermediate (or intrepid beginner). Requires basic knowledge of soldering, use of hacksaw and utility knife, software installation, and following software tutorials. Passing familiarity with these topics and a willingness to learn will get you through this Instructable!

Build Time: 8-10 hours for an expert in above topics; 16-20 hours for beginner/intermediate.

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thanks for that intresting guide. Just had a few ideas by reading it.
sunnyy3 years ago
sir plzz tell me that how this interface works with the software. . what software i have to install and how it install. . this is also my final year project.and im started on working on it. plzzz tell me the complete detail and description. . . i shall be so grateful to you
tinker2344 years ago
hey could i use a PS3 camera i heard they work great
tinker2344 years ago
hey could i do alyer of infreid leds then a reciver so that on the surface i can just touch anywhere
tagadac4 years ago
I think it's possible. But it's less expensive to turn a webcam to an IR camera...
75771225 years ago
Can we use IR camera directly instead of converting webcam into IR camera??? Thanks.
yes sure u can
TheIronHobo5 years ago
did you make the one in the video?
MK2MR25 years ago
^ I'd like to know that as well
the idea of this project is to allow the webcam to see the infrared light right? so could i just make a stick that emit infrared light ratter than make the screen?

short answer - yes.

one problem - working out how your going to hold multiple IR-emitting pens in one hand. this of course opens up the possiblility for a multi-touch display without an actual box. you could simply wave the pens around in the air in front of an IR camera, and have the pointers show on a monitor.

You can create a glove with ir leds on it, and position the camera so it will react only to some distance in the space (so you can use shut them down like click, or make an button that shut downs the led's when you fully straignten the finger, every one of them, or when you bend them to certain degree. :)
earl_kim6 years ago
nice work! but it couldn't download example patch anymore. anybody has it email me that?
josheee126 years ago
i personally sanded with 400 grit, 800 grit, and the classic "blowtorch method".
UbuntuNinja6 years ago
Nice diagrams!
Please let me know the size of the sheet, thinkness, length and breath.
Sheet size is limited only by the brightness of the light source. As for thickness, I've heard 1/4" works the best.
sambam20067 years ago
For the people who are after IR leds then go here. I got mine from there. They come in strips. Easy installation took me five minutes. Shipping takes over a week. Contact him and leave him a message of your requirements etc.

fangtastic7 years ago
the download is working it's just being renamed weirdly, right click and do a 'save link as' or whatever your browser has as a similar option.

it will then give the file name as 'FH1S374F3KMNVOY.tmp' just go ahead and save to the desktop, or note where you saved it to.

when its downloaded just rename it to Touch_demo_3.v4p and you should be good to go :-)

Also many thanks for the instructible it's fascinating how many ways people are going about this, I had contacted a london based company that specialises in bar's to try and buy their system but their customer service has been so poor, I decided to research further and found this and many other far more exciting ideas. It's not so difficult and I'll get exactly what i want, so now instead of buying I'm going to build!!!

I'm off to the shed, and I won't be back till breakfast :-D
I may be wrong, but couldn't you now use the Wii remote in place of the video camera? (a la Johnny Lee.)
imarzouka7 years ago
Use this led calculator to calculate the resistors you will need for your ir led array
jak067 years ago
what works better? lexan or acrylic
efko7 years ago
very nice! i've got a questions... 1) how about latency/responsiveness of such a thing... can it be used for real-time live music, for entering beats, controlling effects etc.? i'm considering building it, but maybe it want perform enough for what i would use it... 2) are there some requirements for lighting? that is can it be usable under any lighting condition? what about some club interiors, sometimes they love to use these UV lamps, do you think it can affect this somehow?
FarMcKon (author)  efko7 years ago
There is low latency on this, it's only limited by how fast your PC can process the video. IT should do OK under black (uv) lights, but it does not do so well in light that has a lot of Infra-red (ie, bright dayligt, outdoors). I hope that helps
efko FarMcKon7 years ago
Thanks! Though don't know what "low" exactly means:-) It's clear, that the processing machine probably won't do much more useful stuff then multitouch handling... But that could be OK. Anyway thanks for nice guide!
nuiman7 years ago
Check out http://nuigroup.com to learn more :) great tutorial thanks!
When modifying the webcam is it possible you could brake the computer?
FarMcKon (author)  shadowsrevenge7 years ago
Not at all, there is 0.001$ chance of breaking the computer. Even if you work on it plugged in (DON"T do that) you would at most ruin the one USB port you are plugged into. Now, having letting something fly across the room because you were prying too hard, that is possible. Don't work on this right next to you LCD monitor, for example.
digilevi7 years ago
HI FarMckon, this is a very good instructable, however i`ve some questions. 1) can i see my desktop on the table top? 2)shouldi run vvv together with the appz i want to manipulate(ex. photoshop)? 3) can u give us a demo video in manipulating some popular appz. thanks. more power to you cheers
so with this handy stuff i can like control my computer? like something i can use during a powerpoint presentation to control the pc without walking back and forth? and will more LEDs increase performance or accuracy? how many should i use? thanks
FarMcKon (author)  J50Nunlimited8 years ago
Yes, using this you can control you PC, but not a 'walk away' type of thing. It's like a homebrew Lemur Pad.

For my 8in x10in demo, I used 5 LED's and it worked great. An LED every 2 inches or so works for small boards, I can't recommend something for board over 15in or so, since I've not built one yet.
what do you mean by "not a walk away type"..."homebrew"?? does this mean like i CANT use the touchscreen to click the start menu and stuffs?
FarMcKon (author)  J50Nunlimited7 years ago
I mean that your hand has to be in contact with the touch surface to use it. You can't wave your hand a few feet away and have it accept commands. If you are using it in a projector room, you would need to have a long USB cable connecting your touch-box (sitting next to you) to the computer/projector you are using (sitting somewhere else). In this case "Homebrew" means it works similar to a commercial product, but it's built at home a lot cheaper. In this case, it not as good quality as the commercial product either.. You can use it to click start, etc, but it's more useful for situations that need multiple inputs at once. Such as playing digital piano/keyboard, various video games, etc.
Neodudeman8 years ago
lol. icanhascheezburger?
hi how do you power the LEDs becaue i attached mine to a 1.5v battery and they blow up
An LED is designed to run at a certain voltage and to draw a certain amount of current. If you exceed this rating it will overheat and burn out. When you get your LEDs they will have a specification sheet usually on the back of the package, or you can look them up online. Let's say that your LED runs on 2.2vdc and is supposed to draw 20mA of current. (That's 0.020 amps) So... how do you connect it without it blowing? Let's say you have a 5 volt power supply... 5 volts minus 2.2 volts is 2.8 volts. We know that we need to control this additional 2.8 volts to never exceed the 20 mA (0.020 Amps). 2.8 volts divided by 0.02 is 140. So we will need about 140 ohms of resistance... a quick trip to Radio Shack or other supplier and we find that the nearest resistance is 150 ohms. This will work just fine. In the discussion below... if we were to insert a 1K (1000 ohm) resistor, the formula would be... 2.8 volts divided by 1000 is 0.0028 amps... or 2.8 mA far below the operating current specified... they would be VERY dim indeed! Jerry
Agree with mrdspecs, you need a current-limiting resistor. 1k sounds a little high, typically regular LEDs will take 5-10 mA, at 1.5V means you want 300-150 Ohms, respectively. Just put it in series with the LED, so +battery -> resistor -> led -> -battery.
You need to put some sort of resistance in there. You can't just run the battery through the LED because all your electrons get out. Get like a 1k resistor at radioshack.
FarMcKon (author)  cheesemaker1018 years ago
What are you seeing that indicates they are burnt out? Are they getting extremely hot when they do that? What type/brand of battery are you using, just a standard AA battery? I'd like to help, but I don't have enough info to go on from your post so far.
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