A proximity sensor measures receptor output with an energy source deactivated. The sensor then measures receptor output with the energy source activated. The measurements with the energy source activated are compared to the measurements with the energy source deactivated to compensate for the effect of ambient conditions. A near condition is recognized if the change between the two groups of measurements exceeds a designated value. To compensate for receptor output that may decrease after reaching a peak value during approach of an object, a near condition can be maintained until the change between the two groups of measurements no longer exceeds a different designated value. Multiple sensors can be used to avoid false near conditions caused by, e.g., placing a device equipped with the sensors next to a stationary object. In one embodiment, a sensor comprises an infrared light emitting diode and a phototransistor.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 10/753,343, filed Jan. 9, 2004 and titled "Proximity Sensor with Adaptive Threshold," now U.S. Pat. No. 6,933,922, which application is a continuation of U.S. patent application Ser. No. 10/058,384, filed Jan. 30, 2002 and also titled "Proximity Sensor with Adaptive Threshold," now U.S. Pat. No. 6,703,599. This application is related to U.S. patent application Ser. No. 11/055,658, filed concurrently herewith and also titled "Proximity Sensor with Adaptive Threshold." All of said applications are hereby incorporated by reference in their entirety.
A wireless human interface device (HID) includes an input interface module for accepting inputs from a user; a microprocessor for processing the accepted inputs; a wireless transmitter for transmitting the accepted inputs to a host; and a temperature sensor for determining the temperature of the wireless HID, wherein the microprocessor transmits the sensed temperature via the wireless transmitter to the host for displaying.
