|Advanced Physics Projects for School & Home|
|open source science on a budget|
This is a project to develop and open-source magnetic gradiometer for archaeological surveying. The sensor head consists of two flux-gate magnetometers per pole which appear to give an effective resolution of 1-2 nT. The output of the senors is a TTL signal whose frequency typically sits at around 60-80 kHz, the difference between their frequencies indicating the field gradient. Unlike some other projects no mechanical adjustment for zeroing is required. The frequencies are measured using a Teensy 3.2 board along with the temperature at each senor to allow for thermal drift adjustment. The Teensy calculates the field gradient outputting to a Raspberry PI for further processing and local storage.
Thant's the easy bit. Mapping the data is time-consuming.