often simpler is better — when you don’t need the the computational power of an onboard microcontroller, it’s typically best to rely on a basic circuit to get the job done. With low-cost Raspberry Pis and ESP32s all over the place, it can be easy to forget that lots of simpler projects can be completed without a single line of code (and with the ongoing chip shortage, it may be a lot more crucial now than ever to remember that).

[mircemk] had the ideal idea when he built his basic induction-balance metal detector. It uses a couple of 555 timers, transistors, and passives to sense the presence of metallic objects by means of a coil of wire. He was able to discover a coin up to 15 cm away, and larger objects at 60cm — not bad for a pile of components you probably have in your bench’s spare parts drawer ideal now! The detector selectivity can be tuned by a couple of potentiometers, and in true metal detector fashion, it has a buzzer to loudly blare at you once it’s found something (along with a LED, in case the buzzer gets too annoying).

All in all, this metal detector looks like a extremely fun project — one perfectly suited to beginners and a lot more seasoned hackers alike. It serves as a terrific tip that not every project needs WiFi or an OLED display to be useful, but don’t let that stop you from overdoing things! If touchscreens are a lot more your speed, [mircemk] has got you covered with a smartphone-integrated version as well.