I’m looking to hack a simple project together and was wondering if the Vex h-bridge in the motor controller is good or if I need to buy something else. PWM signal in, motor power out. Sizes of motor are TBD but less powerful than Vex motors.
Anyone know the actual h-bridge inside the Motor Controller 29 part? I don’t want to destroy one off hand but may have to do so.
The specs on the web page say 4A at 8.5V while the linked data sheet says 3A at 8.5V.
And there’s another PIC controller in there too? So much more to learn!!!
Anyway, would this MC29 control a simple small motor if there was less voltage (say up to 6v) coming in on the MC29 part? Say an Arduino giving the PWM signal… Looking to avoid a whole other shield layer if possible.
And there’s another PIC controller in there too? So much more to learn!!!
Four fets are needed for the H-bridge, why this solution? probably cost. Also RC style pwm is not as easy to handle as continuous pwm. Most single chip H-bridges do not handle RC style pwm.
It would probably work, again, make sure you use the right type of pwm signal.
Adding to what James said about needing the right PWM signal:
The PIC is converting a standard servo pulse duration signal into 1.14kHz PWM for the H bridge. Needed this info for another project too so just confirmed with oscilloscope. 18ms Period and 1.5ms neutral pulse duration. Minimum (-100 power) = 1.0ms and Maximum (+100 power) = 2.0ms so nothing special, just standard servo control.
The Cortex generates a 3.3V level servo pulse signal. My best guess, without breaking one open, is the MC29 has the PIC12HV615 variant which can run from 2-15V owing to an internal shunt regulator. You could safely drive it with a 5V control signal and a standard servo control library (not PWM!).
