This week, I focused on determining the appropriate sizing for the capacitive touch grid, including the spacing required for a 9 x 9 grid system. Since our system only needs to detect one input at a time, rather than handling multiple simultaneous touches, I realized we could allow for slightly more spacing between the capacitors without sacrificing functionality.
Based on this, I designed a 12in x 12in grid using 1-inch-wide copper foil strips, with 0.375-inch (3/8-inch) gaps between each strip. This layout results in 1-inch by 1-inch capacitor squares, separated by 0.375-inch gaps.
Additionally, I plan to test different dielectric materials to determine which works best, including parchment paper and packing tape.
I do feel slightly behind schedule, as I had hoped to have the board built and begin testing with the MPR121 sensors by now. However, since the sensors have not yet arrived, and I had a fairly busy week with multiple projects, exams and assignments I fell behind.
Therefore my next steps will be to:
- Start writing pseudocode for the Raspberry Pi to prepare for debugging.
- Build a test grid to begin preliminary experiments as soon as the sensors arrive.
- If the MPR121 arrive, do testing as soon as possible and possibly begin working on implementing the full 9×9 grid.
