jim hamblen
An Experimental IMU demo with some initial mag calibration code.
Dependencies: LSM9DS1_Library_cal mbed
This IMU demo prints to the USB virtual com port. It includes initial calibration, and scales the IMU readings to meaningful values that are printed out.
Revision 0:e693d5bf0a25, committed 2016-02-03
- Comitter:
- 4180_1
- Date:
- Wed Feb 03 18:47:07 2016 +0000
- Commit message:
- ver 0.0
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/LSM9DS1_Library_cal.lib Wed Feb 03 18:47:07 2016 +0000 @@ -0,0 +1,1 @@ +https://developer.mbed.org/users/4180_1/code/LSM9DS1_Library_cal/#36abf8e18ade
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Wed Feb 03 18:47:07 2016 +0000
@@ -0,0 +1,79 @@
+#include "mbed.h"
+#include "LSM9DS1.h"
+#define PI 3.14159
+// Earth's magnetic field varies by location. Add or subtract
+// a declination to get a more accurate heading. Calculate
+// your's here:
+// http://www.ngdc.noaa.gov/geomag-web/#declination
+#define DECLINATION -4.94 // Declination (degrees) in Atlanta,GA.
+
+DigitalOut myled(LED1);
+Serial pc(USBTX, USBRX);
+// Calculate pitch, roll, and heading.
+// Pitch/roll calculations taken from this app note:
+// http://cache.freescale.com/files/sensors/doc/app_note/AN3461.pdf?fpsp=1
+// Heading calculations taken from this app note:
+// http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/Defense_Brochures-documents/Magnetic__Literature_Application_notes-documents/AN203_Compass_Heading_Using_Magnetometers.pdf
+void printAttitude(float ax, float ay, float az, float mx, float my, float mz)
+{
+ float roll = atan2(ay, az);
+ float pitch = atan2(-ax, sqrt(ay * ay + az * az));
+// touchy trig stuff to use arctan to get compass heading (scale is 0..360)
+ mx = -mx;
+ float heading;
+ if (my == 0.0)
+ heading = (mx < 0.0) ? 180.0 : 0.0;
+ else
+ heading = atan2(mx, my)*360.0/(2.0*PI);
+ //pc.printf("heading atan=%f \n\r",heading);
+ heading -= DECLINATION; //correct for geo location
+ if(heading>180.0) heading = heading - 360.0;
+ else if(heading<-180.0) heading = 360.0 + heading;
+ else if(heading<0.0) heading = 360.0 + heading;
+
+
+ // Convert everything from radians to degrees:
+ //heading *= 180.0 / PI;
+ pitch *= 180.0 / PI;
+ roll *= 180.0 / PI;
+
+ pc.printf("Pitch: %f, Roll: %f degress\n\r",pitch,roll);
+ pc.printf("Magnetic Heading: %f degress\n\r",heading);
+}
+
+
+
+
+int main()
+{
+ //LSM9DS1 lol(p9, p10, 0x6B, 0x1E);
+ LSM9DS1 IMU(p28, p27, 0xD6, 0x3C);
+ IMU.begin();
+ if (!IMU.begin()) {
+ pc.printf("Failed to communicate with LSM9DS1.\n");
+ }
+ IMU.calibrate(1);
+ IMU.calibrateMag(0);
+ while(1) {
+ while(!IMU.tempAvailable());
+ IMU.readTemp();
+ while(!IMU.magAvailable(X_AXIS));
+ IMU.readMag();
+ while(!IMU.accelAvailable());
+ IMU.readAccel();
+ while(!IMU.gyroAvailable());
+ IMU.readGyro();
+ pc.printf("\nIMU Temperature = %f C\n\r",25.0 + IMU.temperature/16.0);
+ pc.printf(" X axis Y axis Z axis\n\r");
+ pc.printf("gyro: %9f %9f %9f in deg/s\n\r", IMU.calcGyro(IMU.gx), IMU.calcGyro(IMU.gy), IMU.calcGyro(IMU.gz));
+ pc.printf("accel: %9f %9f %9f in Gs\n\r", IMU.calcAccel(IMU.ax), IMU.calcAccel(IMU.ay), IMU.calcAccel(IMU.az));
+ pc.printf("mag: %9f %9f %9f in gauss\n\r", IMU.calcMag(IMU.mx), IMU.calcMag(IMU.my), IMU.calcMag(IMU.mz));
+ printAttitude(IMU.calcAccel(IMU.ax), IMU.calcAccel(IMU.ay), IMU.calcAccel(IMU.az), IMU.calcMag(IMU.mx),
+ IMU.calcMag(IMU.my), IMU.calcMag(IMU.mz));
+ myled = 1;
+ wait(0.5);
+ myled = 0;
+ wait(0.5);
+ }
+}
+
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Wed Feb 03 18:47:07 2016 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/165afa46840b \ No newline at end of file