I'm trying to build a 20"x20" touch surface made from glass, divided into a chessboard with 1" squares. I want each square to have an LED light behind it that turns on or off when touched. The challenge I'm facing is making the surface responsive to touch. I've looked into options, but I'm not keen on buying something pre-made. I need it to be resistive or capacitive since an IR light matrix won't work for my needs. I could really use some creative ideas or DIY techniques for making this touch surface!
3 Answers
Have you thought about using photoresistors under each square? You could keep them separate and use IR light from above to create a uniform light scenario. Your finger would cast a shadow, indicating a touch. It's a cheap solution too since photoresistors are pretty affordable. But keep in mind you’d have to wire a lot of sensors to make it work effectively, around 400 for the whole setup!
One way to go is by using acoustic sensors that can detect taps. You could put mics on each side to find the x and y coordinates. Since your resolution needs are pretty low, this might just fit the bill. A more industrial approach would involve a transparent conductive layer on the glass, but that requires specialized equipment and safety precautions due to the chemicals used. Alternatively, if you're okay with some compromise on transparency, a capacitive sensor PCB could do the job if you can position it correctly beneath the surface. Hmm, do you really need to see right through the glass? That could change your options a bit!
You might want to check out Transparent Conductive Film (TCF). It's what’s typically used in touch panels, and it is indeed possible to create a larger screen from it if you manage to get your hands on the right materials. Reaching out to suppliers for sample sizes could be a good start to see if you can build this yourself.