0 Build a Simple Robotic Metal Detector (part three)

Building a BFO Metal Detector

This is part three of four in a series on how you can make a metal detecting sensor for your robot. If you have missed the previous article go here to view it: http://robotrecycled.blogspot.com/2012/02/build-simple-robotic-metal-detector_07.html.

Here is a list of parts that you will need to build your metal detector. For this project I am connecting the metal detector to an arduino programmable controller ($30.00 from RadioShack). If you want to build just a regular metal detector that just makes sound all you have to do is replace the arduino with an 8 ohm speaker. This is also a handy thing to keep in mind if you have to troubleshoot this device.

At this point you will be assembling the circuitry of the metal detector. You will need all of the following items from the parts list along with a robot to install your metal detector on when you have completed this series as this tutorial assumes that you already have a robot.

• Parts list:
• Any 9v battery
• Small Gauge Copper Wire (J1, J2)
• 2x 220uF 16v electrolytic capacitor (C11, C12)
• 5x 0.01uF polyester capacitor (C6, C7, C8, C9, C10)
• 0.1uF polyester capacitor (C1, C2, C3, C4, C5)
• 10k 1/4 watt 5% resistor (R1, R2, R3, R4, R5, R9)
• 2.2m 1/4 watt 5% resistor (R6)
• 39k 1/4 watt 5% resistor (R7, R8)
• 2N2222A transistors - almost any NPN transistor will work (Q1, Q2, Q3, Q4, Q5, Q6)
• Arduino Uno
• Basic Stuff: wire, solder, soldering iron
• Search coil (I1)
• Reference  ocilator (I2)

(Click on this image to view it larger)

Completing the circuit:

(Click any image to view it full screen)

Line up the parts with the corresponding symbol on the schematic.

All of the parts should line up as shown above and just follow the schematic to assemble everything.

connection points to larger parts.

Fully assembled circuit.

Continue to part four -->