I'm working on a project to apply touch sensitivity to a modified pin display (30×30). The goal is to allow someone to interact with the display through their fingers and ideally touch.
We initially looked at detecting touch through capacitive touch sensing on a pin by pin basis, potentially using several pcb layers which would make contact with and allow us to track changes in the capacitance of each pin and therefore touch events. However, this is 900 pins for a 30×30 display and interference between the traces and maintaining contact with the pins could be a problem so we're looking to see if anyone has a better solution that allows us to make this pin display interactive.
We have also experimented with depth cameras (leapmotion) and the current solution is using a computer vision system to track the fingers and an interaction (ask them to push a button) to know if the fingers are contacting the display or not.
Any other novel approaches or better solutions which allow you to track both finger position and if they're contacting the display, would be very useful.
Below is an example of the type of pin display that we were looking at adding touch sensitivity too.
Best Answer
You could replicate the Pin array design with some linear array potentiometer by gluing them vertically on a PCB:
https://www.directindustry.com/prod/bourns/product-11910-205199.html https://www.directindustry.com/prod/althen-controls/product-209349-2243873.html
Then simply measure their resistance with a multiplexed system, might be a bit costly and time taking to make, but will be very accurate.