US Patent 7375644 Foot switch and output system having foot switch

The foot switch includes a pedal, an output command signal generating section for transmitting, when the pedal is operated, an output command signal to an apparatus which has a function of producing active output, a storage battery for supplying electrical power to the output command signal generating section, a condition-detecting section for detecting a remaining capacity of the storage battery, and a notifying section for making notification of an amount corresponding to the remaining capacity detected by the condition-detecting section. The condition-detecting section can detect the remaining capacity based on the remaining voltage of the storage battery.