The "VEX" transmitter is a 6 channel FM transmitter with 2 joysticks that can go up & down and from side to side. On the backside of the transmitter there are 4 buttons which control channel 5 and channel 6. The transmitter controls can be set to tank-style or arcade-style. The transmitter has a host of other features.
This makes it a very cheap way to remote control servos. The only problem is that you can only control servos motors and you need to buy an expensive $149.99 "VEX" microcontroller just in order to do that. That is until now!
Step 1: How It All Works
The chip uses the input from the two buttons on channel 5 to control the input from the "VEX" transmitter left joystick so that it can control 6 motors. The chip uses the input from the other 2 buttons on channel 6 to lock in the high or low output on pin 14 of the motor interface chip.
The motor interface chip has the following features. These features may not work since a receiver may pick up a signal from anywhere. We assume no responsible directly or indirectly from using these parts. WARNING! NEVER USE THE REMOTE ON A ROBOT THAT CAN CAUSE DAMAGE IF IT GOES OUT OF CONTROL. If your robot goes out of transmitter range; the motor interface chip may shut down the motors and give control to a microcontroller if your robot is using one. This may also be true if you turn your transmitter off.
The motor interface chip does not use a serial port to
communicate with other microcontrollers. This means you can use a very inexpensive microcontroller chip to be the brains of your robot.
Putting a low on pin 2 will cause all the motors to operate at half the power level when using the transmitter.