Datalogger for Vector Magnetometer

The goal of this bachelor’s thesis is a development of serial line datalogger, primarily intended for application with vector magnetometers. Circuit diagrams, PCB and firmware design are presented as well as notes on assembly, debugging and testing. The whole system is designed to operate in an outdoor environment. The firmware provides interactive setting of various parameters and operational modes.


  • two fully configurable RS232 inputs (speed, stop bits, parity bits)
  • can support two digital vector magnetometers; one vector + one scalar Overhauser magnetometer GSM-19; two general instruments with RS232 interface
  • can directly parse the data from predefined instruments
  • the device is able to record up to 208 vectors/s for many hours (24h), without losing any data
  • the logger can be powered by internal 6xAA battery or by an external power supply (6-50V)
  • it has RTC with battery back-up, GPS receiver for time synchronization and position estimation
  • the data are logged to SD card with up to 32GB of capacity
  • supports a non-magnetic remote control switch for conducting scalar calibration (data logging on request)
  • based on PIC32MX795F512 from Microchip

Viktor worked hard on this project. At first he designed and built a development platform (later used also for other projects…), than he constructed two final pieces. The basic firmware was ready during submission of the Bachelor thesis, but it took much more time and effort to deliver a final version of the firmware (we requested many changes based on testing and real deployment, but of course the overtime work was paid 🙂

“Outdoor datalogger”
ready for transport…
All PCBs of the datalogger
Development platform….
PCBs again…
PCBs mounted in the PELI equipment case
Measurements at Budkov geomagnetic observatory
Measurements in Slovakia – High Tatras, the very top of Lomnicky Stit
GPS testing at Lomnicky Stit, view towards Belianske Tatry