Steve Marple
Raspberry Pi magnetometer
Power-over-Ethernet is used so that only a single Ethernet cable is needed. The red PCB contains a logic-level translator for the I2C bus and a real-time clock. The fluxgate magnetometer sensors and analogue to digital converters (ADCs) are buried in a soil pipe at a depth of 0.85m for temperature stability.
This is the original prototype version. The single power supply is susceptible to voltage sag under CPU load, which causes downward spikes in the magnetometer data. A newer design uses a DC-DC converter and linear regulator to derive a stable 5V analogue supply.
Raspberry Pi magnetometer
Power-over-Ethernet is used so that only a single Ethernet cable is needed. The red PCB contains a logic-level translator for the I2C bus and a real-time clock. The fluxgate magnetometer sensors and analogue to digital converters (ADCs) are buried in a soil pipe at a depth of 0.85m for temperature stability.
This is the original prototype version. The single power supply is susceptible to voltage sag under CPU load, which causes downward spikes in the magnetometer data. A newer design uses a DC-DC converter and linear regulator to derive a stable 5V analogue supply.