minimu9-ahrs-calibrator.1

.TH MINIMU9-AHRS-CALIBRATOR 1
.SH NAME
minimu9-ahrs-calibrator - Reads raw IMU data on standard
input and outputs an optimal linear calibration.
.SH SYNOPSIS
.B minimu9-ahrs-calibrator
.SH DESCRIPTION

This is a Python 2 script that takes raw IMU readings on its standard
input and uses the readings to compute an optimal linear calibation
of the magnetometer.
The IMU should be rotated through as many different orientations
while generating the input.
.P
The input format consists of lines where each line has the format:
.IP
\fBMX MY MZ [EXTRA INPUT]\fP
.P
where \fBMX MY MZ\fP are integers that represent the raw reading from
the magnetometor.
Extra input on the line after the magnetomer readings is ignored.
.P
When the input stream ends, the script will begin creating an
optimal calibration.
This could take a couple minutes.
When the calibration is ready, it is output on the standard output.
.P
The output format is:
.IP
\fBMIN_X MAX_X MIN_Y MAX_Y MIN_Z MAX_Z\fP
.P
The scaling formulae to convert raw readings to scaled readings are:
.IP
.nf
scaled_x = (raw_x - min_x) / (max_x - min_x) * 2 - 1
scaled_y = (raw_y - min_y) / (max_y - min_y) * 2 - 1
scaled_z = (raw_z - min_z) / (max_z - min_z) * 2 - 1
.fi
.P
Therefore, if the raw X value is equal to MIN_X
(the first number in the calibration), then
the scaled X value would be -1.0.  
.P
The calibration is chosen to make the scaled readings take a shape
that is as close as possible to the unit sphere.
.SH NOTES
This Python script is intended for use with the MinIMU-9 from Pololu,
but it is general and will probably work with any magnetometer.

.SH AUTHOR
.nf
David Grayson <davidegrayson@gmail.com>
http://www.github.com/DavidEGrayson/
.fi
.SH SEE ALSO
minimu9-ahrs(1), minimu9-ahrs-calibrate(1)