untitled

Taking Things Step by Step.........................................................................

Although the circuit is simple, there are a few steps you need to do to assem-

ble it and then put the whole shooting match together, including building the

handle and attaching the circuit to it. As usual, we start with the circuit.

Building a metal detector circuit......................................................

The circuit in this project controls sending a detector signal and processing

the signal that comes back to light up the LED. Here are the steps involved:

1. Place TDA0161 (IC1), 2N3904 (Q1), and four terminal blocks (TB) on
   the breadboard, as shown in Figure 12-4.
   The transistor pinout is shown in Figure 12-5.

IC Inductor

Right-angle

phono pug LED

PVC

45° joint

SPST

switch

Potentiometer Phono

jack

Two-piece

LED socket

Figure 12-3:

Key

components

of the metal

detector.

286 Part IV: Good Vibrations