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Drone-mounted iron detector

A differential magnetic-sensing payload built to find buried ferromagnetic objects from the air. Two separated magnetometers feed a Raspberry Pi, which compares their readings, attaches GPS coordinates, logs the result, and alerts when the field difference crosses a threshold.

Dual-magnetometer detector payload built around a Raspberry Pi on a long wooden sensor baseline

The dual-magnetometer payload, Raspberry Pi, GPS receiver, and long sensor baseline.

Iron-detector payload beside the large quadcopter used to carry it

Payload and carrier drone during integration—the sensor baseline is kept away from motors and power wiring.

Drone, battery, radio controller, and laptop running flight-controller configuration software on a workbench

Flight-controller, radio, battery, and telemetry setup during bench configuration.

How it works

  1. 01The two magnetometers sample the field at opposite ends of a long baseline.
  2. 02Calibration removes the static offset, then the software tracks the difference between the sensors rather than absolute heading.
  3. 03Threshold crossings trigger audio and LED feedback while the GPS position and raw values are written to CSV.

This is specifically an iron and ferromagnetic-object detector, not a general detector for non-ferrous metals.

Payload

Compute
Raspberry Pi 3
Sensors
2× HMC5883L-compatible magnetometers
Sensor bus
PCA9548A I²C multiplexer
Position
u-blox 7 GPS receiver
Feedback
RGB status LED and audio alert
Output
GPS-tagged CSV measurements

Python source

Sensor and GPS readers, calibration, logging, status output, alerts, and hardware self-tests are published in the repository.

View source