Have you found yourself suddenly needing to find a small metal object hidden in the woods? Do not? Well, neither do we.But we can’t say the same thing [zaphod], His family hopes to resolve the dispute by finding the surveyor’s pile marking the corner of their property. This is a perfect job for metal detectors, but since they don’t have a metal detector, A usable unit must be assembled from real garbage.
first, [zaphod] The actual working principle of the metal detector must be studied. After reviewing the advantages and disadvantages of the various methods, it was decided to use a beat frequency oscillator (BFO) circuit. This is not the best design, it may even be the worst, but it can be built with parts at hand, and sometimes this is the most important thing. After packing a 2N3904 transistor, an LM386 amplifier, and every Hackaday reader’s favorite chip 555 timer into a housing with some of their closest friends, it’s time to build the rest of the metal detector.
The sensor coil is made by recycling the wire from the old fluorescent lamp ballast and winding it around the lid of the pail 27 times. It is installed on the end of the broom handle, there are some corner pieces made of PVC sheet, be careful not to use any metal fasteners that will throw off the detector. There is an old drill bit in the middle that can be held by the handle, and the metal detector is complete. It actually looks like a part.
Too [zaphod] Save the day by finding the surveyor’s bet and scouting the family’s plot? Sorry for not working. However, this is not a technical failure. The metal detector does seem to work, although it requires a fairly large object to activate. The real problem is that after more careful study, the surveyor will only put down a wooden stake unless explicitly instructed otherwise. Since they already know where that person is…
If your homemade metal detector can’t find something that has never existed, do you do it? real fail? Just something for meditation. In any case, when even the cheapest smart light bulb is equipped with a microcontroller powerful enough to emulate an early home computer, we are always happy to see someone keeping the old way with a small number of ICs.