Interface library for STMicro LSM303DLH 3-axis magnetometer w/ 3-axis acceleromter. Computes magnetic heading.
LSM303DLH Class Reference
Tilt-compensated compass interface Library for the STMicro LSM303DLH 3-axis magnetometer, 3-axis acceleromter. More...
#include <LSM303DLH.h>
Public Member Functions | |
LSM303DLH (PinName sda, PinName scl) | |
Create a new interface for an LSM303DLH. | |
void | setOffset (float x, float y, float z) |
sets the x, y, and z offset corrections for hard iron calibration | |
void | setScale (float x, float y, float z) |
sets the scale factor for the x, y, and z axes | |
void | read (vector &a, vector &m) |
read the raw accelerometer and compass values | |
float | heading (void) |
returns the magnetic heading with respect to the y axis | |
float | heading (vector from) |
returns the heading with respect to the specified vector | |
void | frequency (int hz) |
sets the I2C bus frequency |
Detailed Description
Tilt-compensated compass interface Library for the STMicro LSM303DLH 3-axis magnetometer, 3-axis acceleromter.
Michael Shimniok http://bot-thoughts.com
Based on test program by and
Pololu sample library for LSM303DLH breakout by ryantm:
Copyright (c) 2011 Pololu Corporation. For more information, see
http://www.pololu.com/ http://forum.pololu.com/
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#include "mbed.h" #include "LSM303DLH.h" Serial debug(USBTX,USBRX); LSM303DLH compass(p28, p27); int main() { float hdg; debug.format(8,Serial::None,1); debug.baud(115200); debug.printf("LSM303DLH Test\x0d\x0a"); compass.setOffset(29.50, -0.50, 4.00); // example calibration compass.setScale(1.00, 1.03, 1.21); // example calibration while(1) { hdg = compass.heading(); debug.printf("Heading: %.2f\n", hdg); wait(0.1); } }
Definition at line 64 of file LSM303DLH.h.
Constructor & Destructor Documentation
LSM303DLH | ( | PinName | sda, |
PinName | scl | ||
) |
Create a new interface for an LSM303DLH.
- Parameters:
-
sda is the pin for the I2C SDA line scl is the pin for the I2C SCL line
Definition at line 94 of file LSM303DLH.cpp.
Member Function Documentation
void frequency | ( | int | hz ) |
sets the I2C bus frequency
- Parameters:
-
frequency is the I2C bus/clock frequency, either standard (100000) or fast (400000)
Definition at line 216 of file LSM303DLH.cpp.
float heading | ( | vector | from ) |
returns the heading with respect to the specified vector
Definition at line 187 of file LSM303DLH.cpp.
float heading | ( | void | ) |
returns the magnetic heading with respect to the y axis
Definition at line 182 of file LSM303DLH.cpp.
void read | ( | vector & | a, |
vector & | m | ||
) |
read the raw accelerometer and compass values
- Parameters:
-
a is the accelerometer 3d vector, written by the function m is the magnetometer 3d vector, written by the function
Definition at line 141 of file LSM303DLH.cpp.
void setOffset | ( | float | x, |
float | y, | ||
float | z | ||
) |
sets the x, y, and z offset corrections for hard iron calibration
Calibration details here: http://mbed.org/users/shimniok/notebook/quick-and-dirty-3d-compass-calibration/
If you gather raw magnetometer data and find, for example, x is offset by hard iron by -20 then pass +20 to this member function to correct for hard iron.
- Parameters:
-
x is the offset correction for the x axis y is the offset correction for the y axis z is the offset correction for the z axis
Definition at line 127 of file LSM303DLH.cpp.
void setScale | ( | float | x, |
float | y, | ||
float | z | ||
) |
sets the scale factor for the x, y, and z axes
Calibratio details here: http://mbed.org/users/shimniok/notebook/quick-and-dirty-3d-compass-calibration/
Sensitivity of the three axes is never perfectly identical and this function can help to correct differences in sensitivity. You're supplying a multipler such that x, y and z will be normalized to the same max/min values
Definition at line 134 of file LSM303DLH.cpp.
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