Building your own metal detector is fun and educational. Although building a traditional metal detector may require a kit (or a thorough knowledge of electrical circuits), you can create simpler versions with home appliances. The fastest way to detect metals is by using the magnetic field of your smartphone. However, a well-known method of making a metal detector is to use a calculator and a radio.
Method 1 of 3: Use a Calculator and Radio to Detect Metal
Step 1. Tune the radio to the highest band in the AM setting
Make sure it's not tuned to a station. You will hear the static tone clearly and continuously. This will allow you to hear any difference in tone when your device detects a metal object.
Step 2. Assemble the search head
Turn on the calculator. Then, place the two devices back to back until you hear a low, steady tone. You may have to place the fixtures at certain angles or distances to achieve that tone.
Step 3. Tape the gadgets in place
Once the calculator and radio produce the proper tone, you will need to tape them in place. If the distance is too awkward to glue the fixtures, install them in that position on a board. That way, the search head will stay steady and working properly while you search for metals.
Step 4. Attach the search head to an axis
An old broomstick or similar stick can be a suitable shaft for this purpose. Use multipurpose tape as a quick and safe method of installing the axle. Another thing you can do is use plastic clamps to secure the two pieces together. Use whatever method works best for your search head shape.
Step 5. Test your metal detector on some homemade metals
First, check that the metal detector works by placing a spoon on the table. Then roll it over the spoon and listen until it beeps or makes a new sound (different from the constant tone it makes). Now you can take it outside or around your house to locate other metal objects.
Method 2 of 3: Turn a Smartphone into a Metal Detector
Step 1. Download a metal detecting app
Smartphones are electrical appliances and as such they produce a magnetic field. There are applications developed that allow you to use your phone's own magnetic field to detect metal objects. Go to your respective app store (which differs from platform to platform) and download the metal detector app.
An example of a metal detector application is the “Metal Detector” application
Step 2. Run your phone over the metals with the app open
Once the app has downloaded, open it. Follow any setup instructions within the app to get it working optimally. When the app has loaded and is ready, start hovering your phone over different metal objects.
Step 3. Observe the measure of the change in the magnetic field
The metal detecting app works by measuring changes in the magnetic field of your phone. As you pass it over the metal, it will interact with that field and the application will detect that interaction. These interactions show up as fluctuations in the magnetic field as you move the phone from object to object.
For example, as you pass the phone over a metal object, the magnitude of the field could increase dramatically, indicating that you have found some metal
Method 3 of 3: Assemble a Metal Detector Kit
Step 1. Assemble the hardware
You can buy metal detector kits that come with various pieces of hardware. Some include a coil and a shaft. Others will only have a control box. Choose the right kit for you and assemble the pieces according to the instructions.
If you choose a kit with less hardware, you will have to make the extra parts like the shaft and spool
Step 2. Solder the circuits
The control box will require soldering to complete all the necessary circuits. You will need a soldering iron or gun to solder the components. If you've never soldered before, consider asking a more experienced person for help.
Step 3. Check the metal detector
Once you've set up the metal detector, you need to put it to the test. Lay different metals on the floor and roll the coil over them. If the coil detects metals, you are ready to grab your new metal detector and start hunting for treasures.