Mini-Multitouch Interface

Step 6 Wiring the LEDs

This section covers all of the wiring you have to do, and covers connecting the LEDs to a power source.

We recommend using 1.5 V 100 mA LEDs, and for the purposes of this Instructable assume you are using a 200mA 3.3V DC power supply (such as a 'wall wort' or hobby power supply). You may need to adjust the wiring of your LEDs based on what power supply you have -- check with someone familiar with electronics if you are not sure how to adjust your wiring.

Solder the LEDs together as shown in the picture below... if you need some practice with soldering, do a test run using some LEDs that are NOT glued into the frame. To test the LED wiring, connect the power supply and point them towards the (IR-filtered) webcam. Run your webcam software: if the webcam is picking up the infrared light, you should see a bright red light on the webcam display (although you won't see any light coming from the LEDs themselves, cause it's infrared!).

Now back to the mini-multitouch display. Once you've wired up the LEDs using your soldering iron (according to the diagram below), point the IR-filtered webcam at the mini-multitouch box from above. Run your webcam software now if you do not already have it running: you should see a glow on the webcam display, along the frame when the infrared LEDs are mounted (but, again, you won't see any light from the actual LEDs!). If you can't see the glow you will need to check your wiring, and possibly consult someone familiar with electronics if you aren't sure how to fix the LED hookup.

A quick note: the glow described above is light-leak, and it is undesirable: we will be taking care of that in the next step so that the only infrared light emitted from the touchsurface is the light that comes from touching it. But, for now, it is a good way to check that your LEDs are wired correctly.

You are so close to having a mini-multitouch display!