DISPLAY :: e-ink (Waveshare 7 inch with IT8951 controller has <1s full refresh rate, also supports partial refresh)

SOUND :: 8 OHM / 8W speaker Visaton K50 connected to Respeaker 2-mic audio out

USB male to female cable, with port exported to the side of the Primer

AUDIO :: Respeaker 2-mic array with additional button

Grove - Gesture is PAJ7620U2 (I2C)

ssh

tricky situation: USB charging 5V, LiPo batterias 3.7V, e-ink controller needs 5V, solar panel gives 7V

diverse circuits for voltage increase (booster, step-up), decrease (buck, step-down) are needed, or current stabilization (photovoltaics) are needed

WittyPi allows us to get current/voltage information, have inner clock, have device with its own boot on, boot off cycles

cute little Voltmeter connected to the third state of the main button