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
Digitally Adjustable Boost Converter
Digipots and opamp
MCU controllable resistor - digital potentiometer (aka digipot)
FAQ https://www.analog.com/en/app-notes/an-1291.html
DAC
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.
MarkT
PWM
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