Multi-Touch Interface on the Cheap(really Cheap)


Introduction: Multi-Touch Interface on the Cheap(really Cheap)

This is my first Instructable so please be nice. This is how to make a multi-touch interface out of you desk for very little money. Finally got a video uploaded,sorry about the bad frame-rate my laptop isnt all that good.

Step 1: Necesary Objects

For this you will need a Webcam, a Glass Desk, software called roboRealm ( RoboRealm download ). For me i mounted my webcam under my desk with ducktape.

Step 2: The Software and Setup

For this step we will be setting up the software to read and interpret the image. You can download this software from there website iI have not perfected the software for using fingers,kinda hard to seperate them,but..., I do have a pen like thing that I built from random things lying around my room that powers up an LED. The file Pen.robo is for using the LED pen thingy,u can use anything that powers up an LED and for added precision you can put an IR filter over the camera that is made from either a floppy disk drive or a completely dark spot from a negative on camera filem strip, And the file Touch.robo is for using hands but is not perfected.

Step 3: The LED Pen Device

The following pictures(sorry about the quality) are my newest version of the LED pen device, in the picture i have about 6-7 LED's attached but you only need 1 or 2 for extra precision

Materials needed are
3 volt small clock/watch battery x 1
Zip tie x 2
Electrical Tape
Switch with 2 wires coming out of it
LED's x 1/2 (your choice)
Penny x1

Steps for it are:
1) take the + side and face it down
2) put a wire to the switch on the - side
3) wrap zip tie tightly around battery so wire is held firmly, cut off excess zip tie
4) put tape on battery and zip tie
5) place penney on tape making shure it does NOT touch the battery
6 place second wire to switch on penny
7) tightly tie second zip tie in opposite direction than first one and cut off excess
8) place squares of tape on top/bottom
9) insert LED(s) by taking the long end and bending it up a little and then further down bending it down so the two wires a further apart but still even and parallel with each other

and make shure the - side touches the penny and the + touches the + side of the battery and when you flip the switch it should turn on, this is a very easy/compact way of doing an LED pointer for this project



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    73 Discussions

    How exactly do you download the files? all i do is click them and it takes me to a blank site thingy and it shows ""

    4 replies

    also teh text in it is 205 0 320 0 TRUE 4 100 1 2 Current Source TRUE -90 0.00 -60 2 TRUE 2 TRUE -1 FALSE TRUE 9 TRUE -1 gui newX 1400 1050 newY...what do i do with this?

    Just save that file as a .txt and then after it is done downlaoding hange the extension to .robo

    very very nice project 4 stars because i had to figure it out a lil by myself idea for a sweet add on: 4 point calibration :)

    The touch one won't register my hand at all. Instead the thing locks onto the backround AND spazzes out I tried putting the thing so it is facing away from the light and my hands would be reflecting the light (night) and it still spazzes out, locked onto a black backround. What is the cause of this? BTW no laser pointer or LED or anything that I could rly use >_>

    1 reply

    The camera with IR filter seems to work better because it only picks up light that is escaping from the IR lens.

    the software doesn´t show me anything. only a grey screen. Why is that? and also I can get any signal or movement. please help!!!

    OMG I want to do this so badly! Sadly, though, I don't have a glass surface I could use, or even clear plastic... or do I.... Well... I have clear plastic that WOULD be usable.. if it weren't for the dips in it. It is from the Serpent's Spiral coaster set thing and it has some things dipped in to separate the areas. Would this work? I would have to use legos or K'nex to hold it up, but that isn't what I'm asking. Would it work? Also, I don't have a usable red/blue/anything LED. Unless I were to use something rly bulky lol.

    2 replies

    send me a picture of what it is your are planning on using and ill tell you how well it can work, and for a LED thing, for a low-cost solution if you want I can tell you how to make a LED light thing with only (2 zip ties, electrical tape, a 3 volt watch battery, a penny and a switch)

    I can't do that and here is why. Well I am using my only camera (a PS2 accessory hooked up to my PC) so if I set it up for the pic I can't take it.

    That's pretty cool. I was playing around with it and found that my 15FPS webcam just isn't fast enough to be translated over a whole screen. So my idea would be to change it to work like the pad on a laptop. Would that be possible? As it stands I have a 1280x1024 screen, and moving the cursor at a decent rate across the screen takes just a few frames, meaning very rough mouse movement. I actually sped it up a lot by disabling "low light boost" in the advanced tab of the video capture area, but I'd still like more tracking like systems.

    i am very impressed with your project, and so i decided to do my version, i have used part of your software in my project a 3d mouse using a web cam. thank-you again for releasing your code as i used it for school :) .
    i have posted it here
    best regards

    Hey, I had a great idea for clicking, I am not sure if it would work yet. The Basic Concept: To move the mouse you hold the pen at a certain height. To click you just move the mouse closer to the glass. I think this would be possible. Just thought I would add a little something.

    4 replies

    I thought of that when I made this but you have to lift it far up from the glass for there to be a noticeable difference in the size of the blob.

    could you use a rubber sheet with a grid on it stretched out over the area and have it detect deformations in the grid?

    Wow man, that's good thinking. Unfortunately, I don't know how to this. Anyone?