Controlling two DC motors with VEX motor controllers and Arduino UNO

Other Hardware Motors, Mechanics, Power and CNC
1

I'm fairly new to Arduino and wanted to control an old RC car (Tyco Super Rebound) with the Arduino UNO. I purchased a motor shield and was able to succesfully get the motors to go forward/backward as desired. Only problem was they weren't getting enough power to rotate the RC car on axis.
Therefore, I ordered two VEX motor controller 29s. This is where I'm having my issues. There are 3-input wires - power, gnd, pwm and 2-output wires-power, gnd. I've attached the output wires to the RC motors and the power/gnd of the input from the 7.2V RC battery. I'm not sure how to use the pwm of the arduino. The VEX motor controller specs (http://www.vexrobotics.com/276-2193.html) say that the PWM Signal: 1ms - 2ms will give full reverse to full forward, 1.5ms is neutral. I've researched the PWM of the arduino and tried several codes I've found to no avail. Could someone please tell me how to power these DC motors with my setup using the arduino PWM? ...I want to be able to have left motor forward while right motor reversed or both motors forward or both motors reverse. Thanks in advance! If you need anymore details from me please let me know.

Tony

2

I admit I have not studied the "VEX Microontroller", but my guess is here that when they write "PWM" they do not mean the "PWM" that Arduino uses to simulate an analog output signal, nut more likely that of a Servo.

My suggestion is to use the Servo library and contrl the signal cable that way. Not that the servoe.write(n) you can enter the microseconds of the pulse width, which (and the reason why I think this is the solution) coincidentlly is in the same range. So (approximate code)

#include <Servo.h>
Servo Left, Right ;
 :
Left.attach(8) ;
Right.attach(9) ;
:
  Left.write(1500)  // stand still
  Right.write(1800) // slow back
  Left.write(1000) ; // full forward

You have to read the servo library code to see this microsecond feature described.