Hobbies And Interests
Things You'll Need
Instructions
Assemble the TR Circuit
Mark and cut a piece of plywood to 5 inches by 3 1/2 inches. Attach the circuit board with small screws.
Mount two oscillators directly across from each other between the left 3 1/2-inch edge and the center of the board. Run a length of magnet wire from the center of the right edge on each oscillator toward each other.
Attach a capacitor to each length of wire and feed into an n-channel FET oscillator. Mount the oscillator to the board.
Run magnet wire from each of the three connection points on the left wall of the two oscillators mounted to the board in Step 2. Create circuit loops by connecting the top and middle wire of the first oscillator with a capacitor and attach a second capacitor to the middle and bottom wires. Repeat with the second oscillator.
Connect the top and bottom wires in each oscillator by attaching a search coil to the end point of each wire.
Run wire from the left wall of the n-channel FET oscillator and attach a low-pass filter before inputting the wire into an amplifier.
Connect a capacitor to the wire between the low-pass filter and the amplifier. Run wire from the front of the amplifier to a loudspeaker and complete the circuit with a capacitor and transfer-type phone jack.
Close the front end of the circuit by connecting a 9-volt battery to the left side of the top oscillator with magnet wire and alligator clips.
Assemble the TR Detector
Mark and cut two circles from plywood, each with a diameter of 5 inches. From the center of one circle, draw across the middle. Mark a half-inch in from both sides. Draw a 2-inch line from the center of the circle perpendicular to the previous line. Use a protractor to complete the arc from the top of the 2-inch line to each end of the 4-inch perpendicular line.
Cut out the partial circle and trace the cut-out onto the second plywood circle. Cut out and place both circles beside each other on the work bench. Place spacers between the two circles and wind coaxial cable around the spacers. Coat the cable with a layer of electrical tape.
Connect the two circles together with small screws and wind the loose end of coaxial cable around one screw head to hold in place.
Assembling the Entire Apparatus
Cut holes for the control knob, socket, toggle switch, aluminum tubing and antenna in the sides of the aluminum casing with a metal saw.
Secure the circuit to the base of the casing with PVC cement and allow to dry.
Insert the antenna, control knobs, socket and toggle switch into the holes cut in Step 1. Connect each piece to the circuit with magnet wire.
Slide rod-mounting hardware on both ends of aluminum tubing. String aluminum tubing onto the loose end of coaxial cable and run the cable out from the end of the tubing.
Connect the coaxial cable to the search coils by threading through the hole in the casing intended for the aluminum tubing.
Attach the exposed ends of the rod-mounting hardware to the detector and circuit ends to finalize the assembly.
Repeat the entire process to create the second TR metal detector for a partner or family member.