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| Three-axis sensor unit. The RJ-45 connector is for power and I2C data signals, not Ethernet. |
AuroraWatchNet is a network of magnetometers for auroral alerts and citizen science. Whilst the magnetometer is intended to function with one single-axis FLC100 sensor from Stefan-Mayer Instruments I have designed the system to support 3-axis operation by mounting 3 sensor boards at 90° to each other using just standard right-angle PCB connectors. This approach avoids the requirement for external mounting hardware which would be expensive to manufacture.
The power supply (a charge-pump DC-DC converter), temperature sensor and RJ-45 connector are fitted to just one circuit board. It is possible to use only one analogue-to-digital converter (ADC) but given their low cost it was presumed they would be fitted to all boards to enable simultaneous sampling of all 3 axes. The MCP3424 converter was chosen because eight options are available for the I2C address, thus jumpers can be fitted to select a unique address for every ADC on the I2C bus. This converter also features 4 input channels. All magnetometer outputs and the temperature sensor are connected to each ADC so that the spare channels can provide some redundancy in case of an ADC failure. The SYNC connectors of all sensors are linked to synchronise their excitation frequencies.
Several single-axis units have been built and one is in active use by AuroraWatch UK. The photograph above shows the first three-axis unit to be built. Initial testing indicates it functions as intended but the performance of 3 simultaneously-powered sensors in close proximity is yet to be established.
Very nice project !
ReplyDeleteAny progress? I'm looking for ways to create a cheap high-sensitivity system for use in archaeological geomapping, and this looks very promising.
ReplyDeleteI've not been using the 3-axis system for the AuroraWatchNet magnetometers as one axis is sufficient. The rest of the hardware is generally working very well and 10 will be shipped out to schools in the next few weeks.
DeleteHi Steve; did you try that before if this 3-axis can use for compass heading? could you send me your mail for more commercial discussion ?
ReplyDeleteYes it can but it is over-specified for that purpose. These sensors are designed to measure very small changes in the magnetic field strength. The magnetometers used in mobile phones are designed to be used for compass heading; they are much, much smaller,lower cost and power and have faster readout.
Deletehi my dear , thank you for your amazing page , I want run a flc100 sensor with nano arduino and send data to pc with blutooth , I need shematic and code , please help , thank you thank you
ReplyDelete