ADXL345: normalize data

3 files changed, 10 insertions, 7 deletions

diff --git a/main.vala b/main.vala
index 60b1c17..c198d75 100644
--- a/main.vala
+++ b/main.vala
@@ -27,8 +27,8 @@ Kinematics kinematics;
 bool loop() {
 	try {
 		/* get sensor data */
-		double gx, gy, gz;
-		int16 ax, ay, az, mx, my, mz;
+		double gx, gy, gz, ax, ay, az;
+		int16 mx, my, mz;
 		gyroscope.get_data(out gx, out gy, out gz);
 		accelerometer.get_data(out ax, out ay, out az);
 		compass.get_data(out mx, out my, out mz);
diff --git a/sensors/accelerometer.vala b/sensors/accelerometer.vala
index b1f9607..95345ae 100644
--- a/sensors/accelerometer.vala
+++ b/sensors/accelerometer.vala
@@ -15,5 +15,5 @@
 
 public interface Accelerometer : Device {
 	public abstract void init(KeyFile cfg) throws Error;
-	public abstract void get_data(out int16 x, out int16 y, out int16 z) throws Error;
+	public abstract void get_data(out double x, out double y, out double z) throws Error;
 }
diff --git a/sensors/accelerometer/adxl345.vala b/sensors/accelerometer/adxl345.vala
index 9c2c58c..3cc8be7 100644
--- a/sensors/accelerometer/adxl345.vala
+++ b/sensors/accelerometer/adxl345.vala
@@ -14,6 +14,9 @@
  */
 
 public class ADXL345 : I2CDevice, Accelerometer {
+	/* ADXL345 3.9mG per LSB */
+	private static const double scale_factor = (3.9 / 1000.0);
+
 	public ADXL345(uint8 dev, uint8 addr = 0x53) throws I2CError {
 			setup(dev, addr);
 			devsetup();
@@ -56,11 +59,11 @@ public class ADXL345 : I2CDevice, Accelerometer {
 		set_byte(0x20, z);
 	}
 
-	public void get_data(out int16 x, out int16 y, out int16 z) throws I2CError {
+	public void get_data(out double x, out double y, out double z) throws I2CError {
 		var data = get_block(0x32, 6);
-		x = data[0] | data[1] << 8;
-		y = data[2] | data[3] << 8;
-		z = data[4] | data[5] << 8;
+		x = (data[0] | data[1] << 8) * scale_factor;
+		y = (data[2] | data[3] << 8) * scale_factor;
+		z = (data[4] | data[5] << 8) * scale_factor;
 	}
 }