Multi-point control corridor timing lights

The circuit is shown below. The control button switches AN1 ~ AN4 can be installed at different positions in the corridor. As long as any button AN1 ~ AN4 is pressed, the lighting L will light up immediately. At the same time, it will be stepped down by the transformer, rectified and filtered, and power will be supplied to the 555 integrated circuit. The initial voltage on the 220μF capacitor connected to pins ② and ⑥ of the 555 integrated circuit is zero, so the pin ③ of the 555 integrated circuit outputs a high level, and the relay J1 actuates, causing the normally open contact J1-1 to close, and the entire circuit enters a timed self-locking state. After that, the power supply charges the capacitors on the ② and ⑥ pins of the 555 integrated circuit, and the voltage rises. When the capacitor charges about 2/3 of the DC power supply voltage, it is the timing time, which takes about 3 minutes. At this time, the output of pin 3 of the 555 integrated circuit flips to low level, so J1 is released, the contact switch J1-1 is automatically disconnected, and the light L extinguished. Just press any button among AN1~AN4 again, and the timer will be reset to turn on the light.