MbPro Compass

From Merlin Systems Wiki

The Miabot Pro Compass module adds a magnetic compass reading capability to the Miabot Pro robot, as an aid to robot navigation.

Image:Compass_detail.JPG detail picture of the compass module

Image:Compass_on_robot.JPG compass plugged into a Miabot Pro

The compass can provide magnetic bearing information with a maximum accuracy of a few degrees.


Contents

Documentation

The manual is here -
Miabot Pro Magnetic Compass v1.0.pdf

This also documents the test / example software (see next section)


Software Support

There is no dedicated 'compass support' command in the Miabot Pro at present. The module is accessed via the generic robot i2c access command "[i]" (see Miabot_Pro_Command_Summary). The module is addressed at the fixed address 0xC0.

A test program is provided with source code (in VB6.0), which demonstrates the use of the compass, and the method of correction to compenstate for the magnetic field of the wheel motors.
Download here - compass demo 1v2.zip

In addition to the program executable, as documented in the main manual, this zip includes the VB6 sourcecode. The sourcecode shows how to access the compass data via the robot, and how to correct for the errors caused by the magnetic field of the wheel motors (see also MbPro Compass Design).


Design

MbPro Compass Design

NOTE includes important details of the practical limitations of magnetic compass readings, and particular problems relating to mobile robots


Build Notes

MbPro Compass Build