Metal Detector Circuit using IC CS209A

This is a simpler metal detector circuit based on IC CS209A. A 100uH coil is used to sense the presence of metal. The IC CS209A has a built in oscillator circuit and the coil L1 forms a part of its external LC circuit which determines the frequency of oscillation. The inductance of the coil change in the presence of metals and the resultant change in oscillation is demodulated to create an alarm. The LED gives a visual indication too. Vary the pot R1 in the circuit to adjust the sensitivity of the circuit. This is much simpler as an inductor is used in place of the coil but you would have to compromise with its range. This circuit can sense metals up to a distance of few inches but usually range is smaller when compared to Metal Detector Circuit using IC TDA2822