Picture of 1, 2, 3, Metal Detector
In this Instructable I will show you how to create a very simple, low cost metal detector. This is not the type of large scale metal detector you can use on the beach however; this can be used for finding where two studs in your walls meet (aka locating the nails), a lost screw, screws, or just simply fooling around testing different objects around the house.

-a 9 volt battery
-9 volt battery connector
-a LED (any color)
-a switch
- a resistor 100 ohm -/+5% color bands are: brown, black, brown (needed for the 1.5v LED)
-and of course a metal sensor. I got mine from, but you can try a number of different robot part sites or electronic components suppliers. try and get one with a LED built in that way you can see if the metal detector works when it touches metal.

OK lets get started!

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Step 1: The circuit

Picture of The circuit
The circuit is very simple. For assembly please follow the provided circuit diagram. Remember that the LED and metal Detector are polarity sensitive. I ask you strongly to test each component before soldering them all together.

Step 2: Test

Picture of Test
flick the switch or hold it down, depending on what type you used. hold the detector to some metal and if the light inside lights up, its metal!

the LED is simply to let you know there is power going to the metal detector.

A video of the metal detector in action

jonman246805 years ago
What metal sensor did you use? I can't seem to find one online.
TXTCLA55 (author)  jonman246805 years ago
Its a SunX Metal sensor. Here is the company web page with all the information on the sensor. I acquired mine through a store in my area So I am not sure how you would go about ordering them (cannot find buying options on the web page) unless you were to buy it off ebay or something. Sorry I cannot help you more but i hope this helps you.
skydive1025 years ago
i like the beeping :)
Blaik5 years ago
this may be useful in checking a car body for damage (would not light up when over a surface that has bondo fill) might be something to see how well it works for that purpose.
robot1175 years ago
cool idea!!!!!!
NachoMahma6 years ago
. I don't know if it will work with your sensor, but your battery should last longer if you put the LED/resistor in series with the sensor.
TXTCLA55 (author)  NachoMahma6 years ago
Series? I put them in parallel because this way the sensor get the power it requires (9 volts) and the LED (with resistor) would get its required voltage as well. If in series the LED would use some power and leave not enough left to power the sensor, hence they have to put in parallel in order to share the amount of current and function properly.
. As I said, it may not work. ;) Since there will be a voltage drop across the sensor, you can use a smaller resistor (maybe none), which will mean less voltage drop across the LED/resistor. . Worth a try. I don't see how it could harm the sensor - if I'm wrong it just won't work.
TXTCLA55 (author)  NachoMahma6 years ago
oh, no its the LED the battery can and will harm if the resistor isnt there. i am sure you know what happens if you try to hook up a 1.5v LED to a 9 volt battery right?
. But the sensor has to have some resistance or it couldn't get power. If it has enough resistance, you won't need the resistor. Use a pot to experiment. The worst you can do is burn up a cheap LED.
TXTCLA55 (author)  NachoMahma6 years ago
ok, hold on...I think were both taking about the same thing, but in a different'r last post is exactly what I was trying to tell you.
. I don't think we are, but it's not important enough to worry about. It works and, after the new wears off, it probably won't be used for very long at a time.
TXTCLA55 (author)  NachoMahma6 years ago
hg3416 years ago
oh yea this is better then i thought it would be