We believe the most significant risks to the success of the project currently are the feasibility of wireless charging, the maximum number of devices possible through BLE, and the integration of all the components into the 22mm height permitted. For wireless charging, our backup plan is that the microcontrollers can pass through charge to the LIPO batteries via USB. For the BLE issue, we are managing the risk by looking into alternative BLE standards such as bluetooth mesh, with the backup plan to make some of the keys act as receivers pair multiple of the receivers with the central microcontroller. For the integration, we can use low profile cherry switches and cut down on some of the “nice to haves” such as hot swap capabilities to reduce the Z-height.
There have been no changes so far to the design of the system so far as we have not gotten enough parts in to experience any real integration challenges yet.
We have some pictures of a small inductive charger working posted in Zhejia’s status report.