Let's imagine a common problem: you need to find reinforcement in a wall, but you don't have a metal detector at hand. No matter how impossible it may seem, you can make a metal detector for such purposes yourself in just 5 minutes, without exaggeration.
Our device will be based on ordinary Chinese multimeterwhich almost everyone has. The model or brand doesn't matter.
Will need
- Multimeter, if not, order on Ali Express -
- Enameled copper wire 0.3 mm.
You will also need: a tube for a search rod, tape, heat shrink, glue, a piece of wood.
Making a metal detector
We screw 2 self-tapping screws into a wooden strip at a distance of 15 cm. We wind 60 turns of wire around them.
We unscrew the screw, remove the winding, and form a circle.
We take the tube and drill a hole from the edge at a distance of 2-3 cm.
Using a grinder we make a cut.
We insert the coil and secure it with a wooden clip.
To prevent the coil from spinning, we place it on glue.
Let's take it multimeter, cut off the probes, strip the wires at the ends.
We connect to the winding terminals, put on heat shrink and blow with a hairdryer.
We wrap it with tape multimeter and wires to the shank.
The metal detector is ready for use.
How to use. Field testing
Multimeter We set it to “sound testing” mode, which is also a diode test.
Initially, the indicator goes beyond the limits and shows high resistance.
We are searching.
As soon as metal appears in the field of view of the coil, its inductance will change. As a result, the indicator will display a value.
We are trying to dig up a find.
Rinse in water.
A small ingot with metal embedded in it was found.
Setup tip: To increase sensitivity, you can wind a couple of turns from the coil, then the response threshold will be higher. But in this case, there may initially be high values, which will decrease when searching for metals.
Search recommendation: The multimeter does not measure the inductance of the coil, but only reacts to bursts of current changes in the conductor. Therefore, for an accurate search, the coil must always be in motion. If metal gets into it and stands motionless, then the device shows high values; as soon as movement begins, the metal detector begins to “see” the metal.
