I am using transistors and relays attached to pieces of copper tape on the screen to stimulate the touch on the ipad screen. I actually saw two posts on Hackaday that taught me how to do this, and for this project I basically combined those two posts to make this.
Basically, light sensors detect if a tile is white or black.
The arduino than turns transistors on/off based on the sensor values, which turn the relays on/off