I'm trying to build an ESC (electronic speed controller) for three phase brushless motor. I found some intresting circuits but I am trying to build something very easy to do, with mosfet and pc817 and an Arduino.
I am using the DAC of the mcu to sense the voltage of the motor in each coil. So far I had used a resistor divider and worked, but motors vary a lot in voltage range (some are of 11.1V, others even of 22V and more,) so using a resistor divider limitsit to a certain family of motors.
I want to know if it is posible to divide whatever the voltage enter to the DAC pin (40v max) to 0 (or -5v) and 5v without losing the sine wave form.