Prototype 2


Plans for version 2

  • battery level indicator (LCD + DAC converter)
  • 130 Ohm resistors for LEDs instead of 470 Ohm
  • optional remote charger
  • get power straight from PSU when in charge mode (something like TPS2113)
  • add to power board logic level 3.3V
  • brushless DC motors
  • look into adjustable output regulator based on L78M and LS141
  • choose an MCU. Forget about ATMega and RP2040, they don't have integrated battery management, that's why look into nRF52840
  • LCD screen. What is refresh rate on LCD screen with SPI protocol?

Control voltage with microcontroller

Good ref:

Digitally Adjustable Boost Converter

Like TPS61045 or MAX686

Digipots and opamp

MCU controllable resistor - digital potentiometer (aka digipot)




In general if you are not using a digital pot to handle an analog signal originating off-board, you don't need the digital pot, a DAC is the simplest approach. DACs are much more numerous and easy to source too.



The high-frequency switching of the PWM output stage consumes much more power than a low-power DAC or digital trim pot, both of which are DC by nature.

Cascade of resistor dividers and mosfets Motorized potentiometer


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