Proximity detector electronic circuit diagram

This proximity detector electronic circuit diagram use a tone decoder integrated circuit ( NE567 ) that will provides a signal with a frequency about 100Khz . This signal is fed to one sensor . The sensor can be constructed from two cooper or aluminum plates  or wires or other conductive material .
When an object is placed near the sensor ,  the capacitance between sensor is  increased . The Q1 and Q2 transistors will amplify the signal and fed it to the   NE567 IC  , that will make the LED1 to glow .

C8 and R4 phase shift the VCO signal from the NE567 so that the U1 can detect its own output signal .
This proximity sensor electronic device require a 9 volts DC power supply circuit .