Digital Fluxgate By Micro-controller

Fluxgate sensor is used to measure weak magnetic intensity such as the earth's magnetic field. Traditional fluxgate adopts analog circuit to process its output signal. Its temperature stability is not so good as the analog circuit will be influenced by the temperature change. This paper studies a new kind of fluxgate sensor that uses digital method to process the output signal.Different with the FPGA or DSP methods, this sensor uses a micro-controller C8051F064 to perform the process. The output signal of fluxgate is sampled by A/D of micro-controller. Then the signal is phase-sensitive rectified and filtered. At last , the digital output is transmitted to computer by serial port RS232. The output of fluxgate is changed to digital signal that is in proportion to value of measured magnetic filed. The paper discusses the design of the hardware and software .The experiment is done by measuring horizontal magnetic filed of the earth using the sensor mentioned above. The result is satisfied and will be perfect using closed loop structure.The experiment result shows it is feasible to use the micro-controller for digital fluxgate. Its temperature stability is better than the analog circuit fluxgate and it is cheaper than FPGA or DSP methods.