v0.4 Electrical Plan

TODO before v0.4 order

• determine why/if battery 5V jump start is needed
• test and integrate the external PDM microphone board
• test more GPIOs - LED indicator, capacitive touch

Must Have Changes

Fix bugs from v0.3

• connect 3.3VA to 3.3V
• change TP4056 to correct package, or replace it
• work with mechanical for better mounting holes
• fix silk screen so all is printed
• boards sometimes need 5V jumpstart to run off of 3.7V battery

Add Speakers

• find smallest speaker we can use with ESP32 (see v0.4 scratchpad wiki page)
• work with mechanical to get proper positioning
• integrate into current board

More Microphones

• select true I2S microphones (see v0.4 scratchpad wiki page)
• change external microphone board to incorporate I2S microphone

Power / Battery Management

We need a more efficient power solution that works from ~4.3V down to ~2.7V to use the full range of our LiPoly batteries. We also need a discharge and charging solution that balances the batteries for safety and longevity. We also want a coloumb counter so we can always know the current charge state of the device.

• choose battery scheme, charging IC(s), voltage IC, columb IC
• integrate into board

• see v0.4 scratchpad wiki page for list of possible chips to incorporate

Review

• onboard CH9102 UART - is it working ok?
• are the test points ok. Footprint ok?
• chip antenna, acceptable range?

Maybe, good to have

LED indicators

• choose RGB LEDs
• work with mechanical to identify placement - on endpiece sensor boards?
• integrate 2+ user-facing RGB LEDs into current design