Big modifications, but most importantly added NED and ENU frame supports.

.codespellrc

@@ -1,7 +1,7 @@
 # See: https://github.com/codespell-project/codespell#using-a-config-file
 [codespell]
 # In the event of a false positive, add the problematic word, in all lowercase, to a comma-separated list here:
-ignore-words-list = ,
+ignore-words-list = ned, enu
 check-filenames =
 check-hidden =
 skip = ./.git

examples/Visualize101/Visualize101.ino

@@ -1,4 +1,5 @@
 #include <CurieIMU.h>
+// for better performance, compile this code using at least C++ 17.
 #include <MadgwickAHRS.h>
 
 Madgwick filter;
@@ -8,11 +9,15 @@ float accelScale, gyroScale;
 void setup() {
   Serial.begin(9600);
 
-  // start the IMU and filter
+  // start the IMU
   CurieIMU.begin();
   CurieIMU.setGyroRate(25);
   CurieIMU.setAccelerometerRate(25);
-  filter.begin(25);
+
+  // set the Madgwick's filter parameter (beta)
+  filter.setBeta(0.1);
+  // set the IMU update frequency in Hz
+  filter.setFrequency(25);
 
   // Set the accelerometer range to 2 g
   CurieIMU.setAccelerometerRange(2);
@@ -30,6 +35,7 @@ void loop() {
   float ax, ay, az;
   float gx, gy, gz;
   float roll, pitch, heading;
+  float q[4];
   unsigned long microsNow;
 
   // check if it's time to read data and update the filter
@@ -48,19 +54,34 @@ void loop() {
     gz = convertRawGyro(giz);
 
     // update the filter, which computes orientation
-    filter.updateIMU(gx, gy, gz, ax, ay, az);
+    // the first template parameter is the local reference frame
+    // NWU = 0, NED = 1, ENU = 2
+    // the second template parameter is the measurement unit of the gyroscope reading
+    // 'D' = degree per second, 'R' = radians per second 
+    filter.updateIMU<0,'D'>(gx, gy, gz, ax, ay, az);
 
-    // print the heading, pitch and roll
-    roll = filter.getRoll();
-    pitch = filter.getPitch();
-    heading = filter.getYaw();
+    // print the heading, pitch and roll (Tait-Bryan angle in ZYX convention)
+    roll = filter.getRollDegree();
+    pitch = filter.getPitchDegree();
+    heading = filter.getYawDegree();
     Serial.print("Orientation: ");
     Serial.print(heading);
     Serial.print(" ");
     Serial.print(pitch);
     Serial.print(" ");
     Serial.println(roll);
 
+    // get and print the quaternion
+    filter.getQuaternion(q);
+    Serial.print("Quaternion: ");
+    Serial.print(q[0]);
+    Serial.print(" ");
+    Serial.print(q[1]);
+    Serial.print(" ");
+    Serial.print(q[2]);
+    Serial.print(" ");
+    Serial.println(q[3]);
+
     // increment previous time, so we keep proper pace
     microsPrevious = microsPrevious + microsPerReading;
   }

keywords.txt

@@ -12,11 +12,17 @@ Madgwick	KEYWORD1
 # Methods and Functions (KEYWORD2)
 #######################################
 
+setBeta	KEYWORD2
+setFrequency	KEYWORD2
+getQuaternion	KEYWORD2
 update	KEYWORD2
 updateIMU	KEYWORD2
-getPitch	KEYWORD2
-getYaw	KEYWORD2
-getRoll	KEYWORD2
+getPitchDegree	KEYWORD2
+getYawDegree	KEYWORD2
+getRollDegree	KEYWORD2
+getPitchRadians	KEYWORD2
+getYawRadians	KEYWORD2
+getRollRadians	KEYWORD2
 
 
 #######################################