Multitouch interface: LED frame


Today I was building the LED frame that will light the acrylic panel. As I wrote before, for the prototype I’m building I’m using two 90cm L-shaped aluminium profiles (the panel is 76cm, but I bought 90cm to use them as a support over the sawhorses). I will put 25 infrared LEDs on them.

I haven’t done any test yet, but I already have some concerns. The profiles are raw aluminium, and probably I should use polished aluminium to help with reflecting the light leaks back to the acrylic. In any case, this is only a prototype, the final version shoul duse polished frames U-shaped to seal the entire panel perimeter.

Drilling marks

Separation between each LED is 3cm aprox., and I will mount them so one side frame will cover the low iluminated point on the other side. To explain it better, where we have a “hole” between 2 LEDs, the other side has one:

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

I printed some templates to paste them over the aluminium, so I can mark the points where I have to drill.

Ruler and LED comparison

The LED thickness is about 5mm, so I’ll use a 5mm drill bit, obviously. The idea is to place LEDs from the back of the frame, attaching them tigh to aluminium, like in the next picture, where I used a regular ruler with a 5mm holeon it.

As soon I drill the holes, the assembly will be like the photography below (I still didn’t drilled, so it doesn’t have the LEDs, but you will notice the appearance it will have):

Tomorrow I’ll do it, and I hope to obtain the wires too (I will use just these wires with a tip similar to hard disk jumpers, so I shouldn’t need soldering the LEDs and resistors.

Tale prototype