These are two different designs to control a vehicle. The joystick is pretty straight forward, it sends a message to the other RCX via infrared, based on the position of the joystick.
The position is based on two sensors. They can measure 3 positions (three colors) each.
When the touch sensor at the top is triggered, the claw of the vehicle will close. In this case it grabs the bottle. I used 10 different IR signals in the program. Messages 1-9 tell the vehicle which direction to go, message 10 will cause the robot to grab or release the bottle. The robot is the 'hunterbot' from this book.
Programs: - Joystick. - Hunterbot.

The 'steering wheel' uses a similar trick. When the thing is tilted, the light sensor detects this. The touch sensors are used to gas and break. More information on how the sensors are used can be found in the programs:
- Steering wheel. - Rover.
All programs were written in NQC.