Difference between revisions of "9. Make a compass"

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[[File:Micropython6.png|thumb|[[1 The basic algorithm]]  ]]
[[File:Micropython2.png|thumb|[[2 WiFI wireless connection]] ]]
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[[File:Micropython2.png|thumb|[[MQTT communication applications]]]]

Latest revision as of 02:39, 21 February 2019

Overview: BPI-Bit


This module gives you access to the built-in electronic compass (mpu). The compass should be calibrated before use, otherwise the reading may be wrong.

note:The alignment compass causes the program to pause until the alignment is complete. Calibration consists of a small game, by rotating the board in the air to complete the circle calibration.

Function of compass

  • compass.calibrate()
Perform this function to start the calibration process, you will receive a has a guiding significance to the information, then we need to rotate the board and in the air to draw a handstand '8' or circle, (this movement can refer to your mobile phone, mobile phone function of compass will have a calibration steps before use), the calibration process will take about 1 minute of time, you can't perform other procedures during calibration
Notice message
  • compass.is_calibrated ()
Returns True if compass calibration is successful, or False otherwise
  • compass.get_x ()
Returns a reading of the strength of the magnetic field on the X-axis, which is a positive or negative integer, depending on the direction of the magnetic field.
  • compass.get_y ()
Returns a reading of the magnetic field intensity on the Y-axis, which is a positive or negative integer, depending on the direction of the magnetic field.
  • compass.get_z ()
Returns a reading of the z-axis magnetic field intensity, which is a positive or negative integer, depending on the direction of the magnetic field
  • compass.heading()
The compass heading calculated from the above readings is an integer between 0 and 360, representing a clockwise Angle of 0 at 12 o 'clock
  • compass.get_field_strength()
Returns the size of the magnetic field around the device, which is an integer.

sample code

   Creates a compass.
   The user will need to calibrate the compass first. The compass uses the
   built-in clock images to display the position of the needle.
from microbit import *
# Start calibrating
# Try to keep the needle pointed in (roughly) the correct direction
while True:
   needle = ((15 - compass.heading()) // 30) % 12

In this sample code the first step is to calibrate the electronic compass (mpu). After the calibration, we can see that we have a compass on the led panel. No matter how we turn the board, it always points to the south. Right