What's the difference and trade-offs between a h-bridge motor controller and a mechanical speed controller for controlling a brushed motor in an RC car?
I have a cheap RC car that I'm trying to retrofit with an Arduino to convert it into a semi-autonomous robot. The car comes with a cheap mechanical speed controller, which seems to be essentially a rotary potentiometer mounted on top of a servo. The controller is also wired into an enormous resistor housed in an aluminium casing. It's motor is a brushed RS-540SH, which the specs say has a stall current of 42A, which I'm guessing is why it has such large resistors.
I could easily wire the mechanical speed controller's servo into an Arduino, but would there be any benefit to using a h-bridge motor controller instead? Based on what I know about each, the h-bridge benefits would be:
- completely solid-state, no slow servo or unreliable potentiometer involved
- ability to electronically brake the motor
while the benefits of the mechanical controller would be:
- it's already there and installed, so I don't need to do anything
- only uses a single DIO pin on the Arduino (vs 3 with a h-bridge)
- completely isolates the motor from interfering with all other onboard electronics
Am I missing anything?
I have a L298N based h-bridge on-hand that's rated for well over the motor's maximum voltage, but it can only handle at most 2A, which is much less than the motor's 42A stall current. Would that be safe to use, or would I be at risk of burning it out my h-bridge?