takuya ichise / HMC5883L

The library for the HMC5883L, which allows you to receive directional information from this library.

Dependents:   Seeed_Grove_Digital_Compass_Example

Fork of HMC5883L by Tyler Weaver

Diff: HMC5883L.cpp

Revision:
1:8a1357c351c6
Parent:
0:8b84d61cee94
Child:
2:8eb755577f83
--- a/HMC5883L.cpp	Wed Oct 31 04:35:08 2012 +0000
+++ b/HMC5883L.cpp	Wed Oct 31 05:06:34 2012 +0000
@@ -127,4 +127,21 @@
     
     for(int i = 0; i < 3; i++) // fill the output variables
         output[i] = int16_t(((unsigned char)data[i*2] << 8) | (unsigned char)data[i*2+1]);
+}
+
+double HMC5883L::getHeadingXY()
+{
+    int raw_data[3];
+    getXYZ(raw_data);
+    double heading = atan2(raw_data[1], raw_data[0]); // heading = arctan(Y/X)
+    
+    // TODO: declenation angle compensation
+    
+    if(heading < 0.0) // fix sign
+        heading += 2PI;
+        
+    if(heading > 2PI) // fix overflow
+        heading -= 2PI;
+        
+    return heading;
 }
\ No newline at end of file