Gyro
From Combat Robot
Two-wheeled combat robots have many advantages: simplicity of construction, high spin rate, fantastic maneuverability, and weight savings. Perhaps their greatest problem is their instability in a straight line – they just don’t go where you point them! Model helicopters have similar problems, and their pilots developed solid-state devices using piezoelectric accelerometers to sense rotation. These became known as ‘piezo gyros’.
The Gyro itself exerts no physical turning force on the robot. It acts by modifying the steering signal from the radio receiver. The gyro plugs into the steering channel of your radio receiver, and the steering servo, on-board mixer, or mixer-equipped motor controller plugs into a port on the gyro. Although very useful in correcting some types of robot control problems,gyros are not compatible with transmitter channel mixing or two-stick tank steering. If your two-channel motor controller includes mixing you're all set. If not, you can buy a stand-alone mixer to plug in between the gyro and your controllers for single-stick control.
Four-wheeled 'bots usually have no trouble maintaining a straight line, but carving a smooth turn can be a challenge. A heading hold gyro can assist 'bots with four or more wheels in maintainig a nice, constant rate turn.
If your 'bot is invertable, make sure your gyro has a remote switch to either turn it off or reverse its output or it will apply reverse correction and your 'bot will death spin.
See also: Beginners guide to combat robot gyros
