Design And Implementation Of Magnetic Compass-digital Converter Based On C8051F350

Magnetic compass is one of the indispensable instruments in ship equipment.People often rely on it to identify the direction when fishing at sea.At present,there are two main types of magnetic compasses used in ships,one is based on traditional mechanically balanced pointer magnetic compass,and the other is electronic compass.Traditional mechanically balanced pointer magnetic compasses are often installed in a relatively fixed position and have low flexibility in use.Generally,the heading angle is displayed by artificially reading a certain position of the pointer on the disc,which will cause artificial reading.Error,resulting in the inaccuracy of the final measured heading angle.Although electronic compass equipment has high precision and is easy to use,it is often expensive,and ordinary small ships cannot afford it.Therefore,In view of this situation,this paper designs a low-cost magnetic compass digitizer that can overcome the difficulty and inconvenience of ordinary magnetic compass reading,and can digitally output the heading angle.This magnetic compass-digital converter circuit module mainly consists of a main controller,a magnetoresistive sensor,a serial port circuit,an LED display and a power converter.Among them,the main controller is the C8051F350 microcontroller produced by Silicon Labs,USA,which has the functions of differential operational amplifier amplification and A/D conversion.And the calculation speed is up to100,000 times per second.The magnetoresistive sensor adopts the HMC1022dual-axis magnetoresistive sensor series produced by Honeywell.This type of magnetoresistive sensor generally has the characteristics of small size,low cost and high sensitivity.The function of the LED display is to directly display the integer value of the magnetic north angle,and those with decimal places can be output to other displays through the serial port circuit for display.Due to the high requirements for wide and voltage adaptability of the power supply and the small and stable electromagnetic interference requirements of the power supply itself,the power converter in this experimental design decided to use MC33063 chip and LM1117 MP chip to complete.After testing,the magnetic compass-digital converter has following characteristics: stable data conversion,0.1 degree heading angle display resolution,conversion accuracy ±1.5 degrees,and maximum data update rate 20 Hz.The minimum data update output rate is 2Hz.