Re: [Electronics_101] Re: motor controller help (VEX)
- A word of caution. PWM by itself does not provide any directional
information. Varying the duty cycle will not change the direction a
motor rotates. Because the output on pins 1 and 2 of a NXT motor port
come from a H bridge the polarity of the signals on pins 1 and 2 change
when the NXT Brick wants the motor to rotate in the opposite direction.
It is also the key reason the Bipolar Mosfet Amplifier uses optical
I don't know what type of signal a VEX controller uses to control a
motor. Seeing as you haven't had any responses from this mail group to
this subject I suggest you try the VEX Forum. See:
However, if a VEX controller uses a method similar to a NXT Brick for
controlling a motor then the same type of Bipolar MOSFET Amplifier
recommended for use with a NXT motor port is recommended for use with a
VEX controller. You could use a H Bridge IC instead of 4 separate MOSFET
transistors to reduce the number of parts. But you will still need 4
Chuck Merja wrote:
> Thanks for all the help!
> Anyone have experience or resources for adding bigger motors to a VEX kit.
> I think the VEX controller actually puts out a PWM, then I'd need some
> and cheap to build H bridge?)
> Chuck Merja