Light controlled shower circuit

The light-controlled shower water saver can ensure that when a showerer stands under the shower head, water will flow out of the shower head, but when there is no showerer under the shower head, the shower head will not spray water, thereby
achieving significant water saving purposes.
    (1) The working principle diagram shows the shower water saver circuit. In the circuit , a Schmitt trigger is composed of two photoresistors , RP and NE555 connected in series
. When there is light, the resistance of the photoresistor becomes smaller, the level of pin ② and @ is high, the output of pin ③ is low, the relay K is not energized,
the contacts are not closed, the DF-1 solenoid valve is not closed, and there is no water supply. . When there is no light, the resistance of the photoresistor becomes larger and the trigger flips. The ③ pin of NE555
outputs a high level, and the relay K is closed, causing the solenoid valve to conduct, and water flows out from the boiler.