/diy/ - Do It Yourself

I have a teensy lc and I am trying to connect 12 (or more if it works) capacitive touch sensors and it only has pins for 11. I originally tried making a grid of lines but realized that if I touch one that it would trigger the other ones it went under/over.

I had a new idea to put them all on the same layer and then when I want to check one (touchRead) first set all the others to high or low so that they dont collect the charge and give a false read. I have a very weak understanding of electricity and unfortunately have to get this finished soon. I also thought to put a big either ground plane or 5v plane under all of the sensors and the columns of sensors would be connected under it so that it doesnt interfere.

Pic related is the top layer of the 'pcb' I am going to diy to test my idea. black are traces.
Anyone have any thoughts on this? I am a programmer and am very new to dealing with microcontrollers and electricity.