Magnetic fields are all around us. We can’t really feel or see them ourselves, per se, but we can map them with the right hardware, like this device built by [edosari50].

The build uses an ESP32 microcontroller, which is built on to a board with an integrated 4.3″ touchscreen LCD. It’s paired with an Arduino Nano, which does the work of actually talking to a pair of EMS100 Fluxgate magnetic sensors. The slower, less capable Arduino handles the low-level chatter and then passes the readouts to the ESP32 over a UART connection. Power is courtesy of a pair of 18650 lithium-ion cells, and a XL4005 DC-DC converter. A lithium-ion charging module is on hand to keep the batteries topped off safely.  Scan results are visualized on the device itself using a heatmap representation, and can also be exported to SD card for later analysis if so desired.

Unless you’re in the geological field or otherwise hunting for stuff underground, this probably isn’t a tool you’ll have a lot of use for. However, if you like finding magnetic anomalies and investigating them, it might be very much in your wheelhouse. We’ve featured other tools for magnetic visualization before, too. Video after the break.