The idea for the coffee table is to have an interactive touch-sensing table to play some simple games, music or just have fun with it.
There are many similar projects, but most of them offer no touch-sensing which limits abilities of the table.
My expected goal is to have 20x20 RGB LED matrix which you control with a simple touch. My extended goal is to convert this setup into a standard MIDI instrument, so you can connect it to your amplifier and have your fund louder.
I'll be using IKEA table with a glass top.
Coffee table with glass top
Nice and powerful controller board which should handle everything
Individually adressable RGB LED for 20x20 matrix
Once I'm happy with basic lighting and touch sensing, I'm planning to add USB port to it so it can act as a MIDI instrument for anything else. This way you can connect iPad and playback your coffee table presses through AirPlay to your audio system.
There are many apps available for it. All you need to do is to buy a USB dongle for your tablet.
I saw several ways of creating a matrix with cells for LEDs, but most of them involved too much special material, wood/acrylic working, and even laser cutting.
Once I was looking for some window blinds for something else, and then I realized that these are perfectly cut and sized for my project. They are cheap enough too. I'll have to make minor modifications to insert one to another one, but that's minor compared to other projects I saw.
I was experimenting with Infrared touch. First I tried to use a normal IR LED, but I got into issues with ambient light. I tried to substract it during calculations, but results were not stable enough for me.
Next thing I tried is to use 38KHz modulated IR LED. The results are much better. However, I need more powerful LEDs to be able to get through the glass surface and able to detect a reflection properly.
It appears that many high-power IR LEDs are not so high power. I tried IR LED from a remote control, that worked nice so I need to be able to get 400 of those without braking a bank.