Battery-powered hand-proximity sensing and control circuit - economises on current from rechargeable battery by employing primary sensor to trigger secondary sensor and driver

摘要

A prim. sensor, e.g. a pyroelectric sensor (16), responding to movement and/or warmth of a hand, can be operated continuously with a current of 20 microamperes or less, causing a monostable (18) to trigger a microampere switch (20) connecting the rechargeable battery (22) to an infrared sensor (10) which drives (12) a motorised valve coil (14). This sec. sensor (10) draws 200 to 300 mnicroamperes and the coil (14) about 300 mA, only when they are activated by the prim. sensor (16) starting the defined cycle of operation. USE/ADVANTAGE - With e.g. wash-basin taps, hand-dryers and soap dispensers; consumption of current from battery is minimised.