This week, I focused on developing a fully functional 9×9 capacitive touch grid. I laser-cut and assembled a new version of the grid, incorporating several design improvements for better usability and stability. While maintaining the 9-inch by 9-inch active area, I added extra border space to separate the wiring and relieve pressure on the connections, which had previously caused reliability issues. The extended edge also allows for clamping, making the overall structure more rigid.
For the top layer, I experimented with 1/16-inch acrylic instead of cardstock to take advantage of its rigidity. Although it initially showed some promise, the material ultimately required excessive pressure to register touches, resulting in inconsistent readings. I plan to revert to a thinner, more responsive material and iterate from there.
There was a minor setback this week: one of the MPR121 ICs was shorted during testing. I’ve ordered replacements and will rebuild the grid once they arrive, continuing to refine the material and construction for optimal performance.
