Mocked up preliminary button and housing components in 3D. Buttons need some kind of retention feature to prevent them contacting the eventual hall effect sensor.
Designed USB-C LiPo charging and power delivery test board using TP4056, DW01A & FS8205. Ordered on OSHPark and saved full-size version as new MS KiCAD template for future use if the test board is successful. This will be the power basis for all near-term handheld math manipulatives. Design based largely on the linked schematic here. 
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