A new version of a technique, based on telemetric devices, to monitor temporal aspects of the activity of homing species of limpets and the parallel recording of sea level oscillations is described. The home/away status of individual limpets was continually assessed by means of a magnetic reed switch. Signals from the reed sensors were transmitted to a distant automatic scanner/receiver, located away from the shoreline. The system can be easily replicated and employed for extensive long-lasting monitoring in the field, even in those cases where previous versions, based on cable connections, were unsuitable.