11024-Me Compass

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[modifier] Documentation

http://learn.makeblock.com/en/me-compass/

The Me Compass module can detect the intensity of surrounding magnetic field, and make the moving device or equipment rotate to specified direction.

[modifier] Spécifications techniques

  • Operating voltage: 5V DC
  • Resolution: 5 mil gauss
  • Dynamic range of magnetic field: ±1~±8 gauss
  • Precision of electronic compass: 1°~2° (Theoretical value)
  • Signal mode: I²C communication
  • Module size: 51 x 24 x 18 mm (L x W x H)
  • Connecting with RJ25

[modifier] Precaution

Me Compass module is rather sensitive to the changes of ambient magnetic field. Therefore, any changes occur to the surrounding mechanical structure or the assembly way of Me Compass may result in the changes of the ambient magnetic field, which then lead to deviation of the measurement result from the Me Compass module.

In this case, users need to calibrate the module to get correct angular value in current circumstance.

Process of calibrating the module:

  1. Connect Me Compass to Makeblock Orion correctly, power on, and then download any one of the compass library we provide.
  2. Press the key on the module until the blue light of the module start flashing, then let go of the key.
  3. During the flashing of the blue light, spin the module (including the mechanical structure connected with it) along the horizontal plane for over 360° steadily.

[modifier] Programmation Arduino

This is a routine to read the angle value detected by Me Compass and output the result to serial monitor through Arduino programming. [[Fichier:]]

[modifier] Programmation Scratch

This program can [[Fichier:]]

[modifier] Fichier d'exemple

Fichier:Sensor.sb2

[modifier] Principle analysis

Traditional compass uses a magnetized needle to induce the magnetic field of the earth. The magnetic force between the magnetic field and the needle spins the needle until the needle aligns itself with the horizontal component of the Earth’s magnetic field (North and South). This also applies to electronic compass, except the needle is replaced by a magneto-resistance sensor. The magneto-resistance sensor will convert the geomagnetic info it receives into digital signal and output it for usage.

[modifier] Schematic

http://learn.makeblock.com/en/wp-content/uploads/2016/01/Me-compass.png

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