Okay. The Plan.
- software
- electrical
- mechanical
is my intended execution path through this project to the MVP.
1. software
I have identified two capacitive touch ic’s that are small enough and contain the requisite features needed to put together this project. Only one vendor however sells a development board that matches the requirements for this project so that is what I am going to be starting with.
The software todo list is as follows:
- Do ic bringup of the vendor dev kit.
- Get vendor dev kit presenting to computer as a pointing peripheral. Using probably using zephyr and the rp2040 to start.
- Add another vendor dev kit and create a compositor so that the 2 dev kits act as one. Will be using both rp2040 i2c peripherals for this.
- Address the Address Problem (capacitive touch ic’s share a single I2C address so they need to be obfuscated from the i2c bus and addressed through another mechanism).
- Update software so that N number of trackpads can be composited.
2. electrical
Will need to design a custom development board pcb with the IC used from the software.
- Design the “top” circuit which will consist of a connector, capacitive touch IC + passives and, the sensor array.
- Design the “bottom” circuit which will consistent of the middle man that solves the “Address Problem”.
3. mechanical
This is the part I have the least experience in. Instead of the todo list, I’ll focus on the requirements:
- Must house the electronics.
- Must fit in existing common key switch foot print.
- Must provide a nice keypress experience.
That is it for now. Will be following up with my individual todo lists.