Went around in circles last year trying to hire a surveyor to find metal property pins …

Couldn’t rent a magnetometer in Tucson.  $500+ to purchase one online.

So I built one out of my standard Arduino Uno brass board.

Two HMC5883L sensors were already on the board.  Seeed I2C shield for multiple I2C sensors.  So I placed the second one at the end of this CPVC pipe in an ABS cap and plug.

builtIT director asked me how I bent the Al support. ‘Wide metal chisel on a vice.’ Scrounged around lab until I thought I had a workable handle.

First trial out I thought I was lucky.

Turned out to be a buried coin cell battery!

Next goal is calibration and a decent user interface.