Bluetooth Based Proximity Sensing for Reactive Mobile Robots

The Bluetooth radio system is an ideal communications tool for lightweight autonomous mobile robots but little research interest has been targeted at this application. Along with facilitating ad hoc communications, other features of Bluetooth may be exploited for use in the mobile robotics domain. We consider the likely scenario where a mobile robot becomes inoperably stuck and unable to free itself. The robot should be able to warn other robots about its situation in order to prevent further losses from the same potential failure. In this paper we demonstrate how the discovery phase of Bluetooth connection setup can provide simple proximity data without requiring an explicit connection to be established. Our lightweight proximity sensing mechanism, tightly coupled to a behavior based control architecture provides a cheap but effective method for kin recognition. Using the latency of the discovery process, we show various proximities can be attained whilst minimising power usage.