Patent ID: 8712085

Claim:
A hearing aid comprising in combination: a) a case containing electronics for processing audio signals, b) a battery for powering the electronics, c) a photovoltaic cell responsive to light for generating an electrical voltage, d) a charging circuit coupled to the photovoltaic cell for charging the battery, e) a voltage comparator having an input coupled to the photovoltaic cell and being responsive to the electrical voltage generated thereby, the voltage comparator including an output for providing a first output signal when the electrical voltage generated by the photovoltaic cell is greater than a reference voltage, and for providing a second output signal when the electrical voltage generated by the photovoltaic cell is less than said reference voltage, and f) a timer coupled to the output of the voltage comparator, said timer detecting changes at the output of the voltage comparator between the first output signal and the second output signal having a duration of approximately 0.2 seconds or longer resulting from variations in the intensity of light incident upon said photovoltaic cell, g) wherein said electronics for processing audio signals is responsive to the timer for controlling the manner in which such audio signals are processed.