Automatic dry hands circuit

Published:2011/5/5 23:04:00 Author:Jessie | Keyword: dry hands | From:SeekIC

This circuit is consists of transimitting and infrared receiving control parts. Infrared transmit partproduces 5kHzfrequency by using 555 time-based circuit, drive infrared tubestransmit infrared light.When hand is under the dryer, because of infrared reflection action, PH302 will receive infrared and change it into electrical signals, by frequency selective amplifier which composed by IC1, IC2,IC3, it's output signal becomes DC signal into IC4 comparator after enlargement, plastic andfiltering. When the input level of IC4 isover 7V, its output changes into low level, trigger IC5 timer starts timing, pin 3 becomes high-level, 3DG130 connected, relay contacts suck close, connect resistance wire and fan.



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