Water and electricity saving faucet circuit 2

Water- saving and energy-saving faucet circuit 2
    The circuit is shown in the figure. It uses 555 time
base integrated circuit A to form a bistable flip-flop. Use
touch control. When the hand touches the "water on" metal piece,
pin 3 of A outputs a high level, and the relay KA and the solenoid
valve Y are closed one after another to supply water; when the hand touches the "water
off" metal piece, pin 3 of A outputs a high level. Low level,
KA, Y are released and water supply is stopped.