R/C Vehicle Control

VEX V5 Technical Support UNOFFICIAL Tech Support
1

(copied from official support forum)

Vex uses standard hobby PWM servo protocol.
Here are some typical issues we come across with BEST Robotics;

You’ll need a male to male pwm cable or adapter for each plug, since Vex uses unshrouded male wires plugging into a female socket on the CPU,
but most RC hobby servos have a female wire tail.

Vex motor ports put out the full battery feedthrough, up to ~8volts,
while some servos are rated for 5v. BEST has burned out a number of 5v servos when they have a static load (stalled).

Vex supports BEST with a new male-male resistor cable.
http://www.vexrobotics.com/products/competition-products/best
and look for products Male to Male array, and Servo Power Adapter;
or make your own.

BEST uses the Cortex, not the PIC controller, but pinout and power are similar. If your ESC has its own battery feedthrough, you’ll probably be fine with the just the MM pin array rather than the resistor wire.

2

Thanks. Since posting my question I have purchased the R/C all terrain truck. The transmitter is obviously designed to provides all of the control functionality needed by the truck. I am starting to think that it might be better to mount a transmitter on the truck, and use the PIC to control the transmitter’s functions.

Not sure if this is feasable, but conceptually it seems like a better approach. The transmitter offers a range of customizable control features that would be retained with this approach.

3

There was an old thread and youtube video showing a Vexnet joystick controlling a robot that used servos to move a older-style 75MHZ Vex transmitter joysticks, which controlled a robot. There was noticable lag.

Depending on what automation you want to be provided by the PIC, it seems like the PIC will need sensors and direct control of the Vehicle motors.