Manipulating the Microcontroller

While waiting for the our VEX challenge my school is planning to participate in the ROV sub-rescue challenge. Last year our team struggled with extensive wiring running to the surface from our robot for video and battery. This year i want to use the vex system to go wireless. First i need to include a new, larger battery. What are the limits of the Microcontroller? What kind of watts/voltage can it handle? I also need to be able to run small propellers, possibly by stripping one end of the extension wires and soldering that to the motor wires. Of course, all of this will be in a water tight container.
(Is any of this is at all possible?)

As always i look forward to hearing your thoughts and ideas.

If I can remember, the maximum voltage the micro controller can handle is 9.6 volts. I would double check with IFI before trying anything though (magic smoke is not fun!).

(EDIT: Don’t use 14.4 that was for the motors)

As for running motors, just buy some cheap speed controllers from banebot or somewhere else that offers a standard PWM interface speed controller. If its PWM it should be plug and play. If your really brave you could rip the controllers out of the back of the Vex motors.

Keep the Vex Controller at 9.6VDC, and I suggest using a Speed ControllerVictor 884 or an H-bridge controller from a Robotics Supply Place to control the Higher Current Motors.

So I have taken off the small circuit board(controller?) from the back of the motor, but now what? Where should I solder the stripped wires from the new motor?

the vex motor is basically a DC motor without the backing (speed controller) so it shouldn’t be too hard.

This thread talks about doing just what you are trying, complete with annotated pictures.

There are also several other threads on using non-Vex motors with the Vex system, so you might find additional useful info if you search the forum for “motor” and/or “controller”.


  • Dean

Thank you that is very helpful