Bedside touch light detection control circuit

Shown is a bedside touch lamp detection and control circuit , which mainly uses a piezoelectric vibration sensor as the core sensing device.
    In this circuit, when the human hand touches the small box equipped with the circuit, the piezoelectric vibration sensor BUZI converts the rotation signal into an electrical signal.
After being amplified by the transistor VT1, it outputs a low-level signal, which is driven by ICl-2 and IC1-3. The buzzer sounds; at the same time. VT2 is turned on, capacitor c3 is
discharged, IC14 works, and its @ pin outputs a high level,\ 13. VT4 is turned on, making the bulb HL light up.