Failsafes monitor the quality of radio signal going to your speed controller from the receiver so if it receives an in-valid signal, interference or no signal at all it will prevent that from reaching the speed controller and making you lose full control of the robot.

When it does sence no signal or receives an invalid signal the failsafe detects this and sends its own signal to set the controller to neutral so your robot should stop dead.

There are mainly two types of failsafes...

Built In Failsafes : These are built into the electronics of the speed controller so its all there ready for you to use.

Plug In Failsafes : Are extra little units that plug in between your receiver and speed controller, and they do the exact same job as the built in ones.

If you tell us what make of speed controller you are using we would be able to tell you if it has a built in failsafe or not, or you can probably find out by reading the documentation that came with the speed controller.

Chris - http://www.featherweights.org/forumBreak