Abstract: A battery operated device such as a road stud comprises a micro-controller, a battery, and a light source. The micro-controller is configured to operate the battery to provide a train of power pulses to the light source, and each power pulse has a characteristic pulse period and a characteristic duty cycle comprising an on-cycle and an off-cycle. The micro-controller is turned on during the on-cycle and turned into a power saving or sleep mode during the off cycle. Setting the micro-controller into the power saving or sleep mode during the off cycle of the power pulse means substantial battery power saved to extend the operation time per charging of the battery.