Incorporated watch code emitter for personnel identification and hands-free use - has battery on watch rear face with IR transceiver and coder on side arms

摘要

The circuit forms an attachment to the back of the watch with a central area (4) behind the watch holding a lithium battery (17). Two side arms (5,6) have bridge sections (7,13) through which the watch strap passes. The side arms have an IR receiver diode on one side and an IR transmitter diode on the other. Interrogation signals are received and processed, and an EPROM microprocessor together with an oscillator feed send coded binary signals to the interrogator. USE/ADVANTAGE - E.g. for access to building or other restricted area. Does not need to be aligned with receiver for codes to be recognised. Insensitive to temp. variations.