Does this help ??

Yes and no, that don't give me the north :), but help me in my quest. I used this script for try , and it don't give the value of the GeomagneticField class but the values of magnet sensor, from sensor class . I will look all of this later. Thanks for your reply

Hi,

I'm trying to use the orientation sensor with ketai library too, but I don't undertsand all the part of the sensor's event.
I have this code, but I only use one event on three from the orientation sensor, so i think there is some unreal north direction ...
And for now, it's a kind of crazy compass :)
this my code:

1. import edu.uic.ketai.inputService.*;
2. import android.content.pm.ActivityInfo;
3. KetaiSensorManager sensorManager;
4. String[] fontList;
5. PFont androidFont;
6. String direction = "";
7. boolean firstdraw = true;
8. float azimuth;
9. float pitch;
10. float roll;
11. void setup()
12. {
13.   orientation(PORTRAIT);
14.   ellipseMode(CENTER);
15.   sensorManager = new KetaiSensorManager(this);
16.   sensorManager.start();
17.   fontList = PFont.list();
18.   androidFont = createFont(fontList[0], 20, true);
19.   textFont(androidFont);
20. }
21. void draw()
22. {
23.   background(0);
24.   // Show compass
25.   showCompass();
26.   printDirection();
27. }
28. void onOrientationSensorEvent(long time, int accuracy, float x, float y, float z)
29. {
30.   azimuth = x;
31.   pitch = y;
32.   roll = z;
33. }
34. void showCompass()
35. {
36.   int cx = width/2;
37.   int cy = height/2;
38.   float radius = 0.8 * cx;
39.   stroke(255);
40.   noFill();
41.   ellipse(cx, cy, radius*2, radius*2);
42.   if (!firstdraw)
43.   {
44.     pushMatrix();
45.     translate(cx, cy);
46.     rotate(radians(azimuth));
47.     line(0, 0, 0, -radius);
48.     text(direction, -25, -radius-5);
49.     ellipse(0, 0, 10, 10);
50.     popMatrix();
51.     // Display value (in degrees)
52.     fill(255);
53.     text(str(int(azimuth)), cx+7, cy+7);
54.   }
55.   firstdraw = false;
56. }
57. public void mousePressed() {
58.   if (sensorManager.isStarted())
59.     sensorManager.stop();
60.   else
61.     sensorManager.start();
62.   println("SensorManager isStarted: " + sensorManager.isStarted());
63. }
64. void printDirection() {
65.   if (azimuth < 22) {
66.     direction = "N";
67.     println("N");
68.   }
69.   else if (azimuth >= 22 && azimuth < 67) {
70.     direction = "NE";
71.     println("NE");
72.   }
73.   else if (azimuth >= 67 && azimuth < 112) {
74.     direction = "E";
75.     println("E");
76.   }
77.   else if (azimuth >= 112 && azimuth < 157) {
78.     direction = "SE";
79.     println("SE");
80.   }
81.   else if (azimuth >= 157 && azimuth < 202) {
82.     direction = "S";
83.     println("S");
84.   }
85.   else if (azimuth >= 202 && azimuth < 247) {
86.     direction = "SW";
87.     println("SW");
88.   }
89.   else if (azimuth >= 247 && azimuth < 292) {
90.     direction = "W";
91.     println("W");
92.   }
93.   else if (azimuth >= 292 && azimuth < 337) {
94.     direction = "NW";
95.     println("NW");
96.   }
97.   else if (azimuth >= 337) {
98.     direction = "N";
99.     println("N");
100.   }
101.   else {
102.     println("");
103.   }
104. }

Somebody can explain to me the good way to use this sensor please ?
Thanks :)