File content as of revision 4:18e9f16cc53c:

#include "mbed.h"
#include "rtos.h"
#include "LSM9DS1.h"
#define DECLINATION -4.94
#define PI 3.14159


AnalogIn infraredR(p20); //Right infrared distance sensor
AnalogIn infraredL(p19); //Left infrared distance sensor
AnalogIn infraredF(p17); //Front infrared distance sensor
Serial pc(USBTX, USBRX);

float leftDist, rightDist, frontDist; //Distances from robot to obstacles
float xaccel, yaccel, zaccel;   //Acceleration in the x, y, and z directions
float xmag, ymag, zmag, head;         //Magnetic readings

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);
    head = heading;
}

void IMU_thread(void const *args) {
    LSM9DS1 IMU(p28, p27, 0xD6, 0x3C);
    IMU.calibrate(1);
    IMU.calibrateMag(0);
    while(1) {
        while(!IMU.accelAvailable());
        IMU.readAccel();
        while(!IMU.magAvailable(X_AXIS));
        IMU.readMag();
        xaccel = IMU.calcAccel(IMU.ax);
        yaccel = IMU.calcAccel(IMU.ay);
        zaccel = IMU.calcAccel(IMU.az);
        xmag = IMU.calcMag(IMU.mx);
        ymag = IMU.calcMag(IMU.my);
        zmag = 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));
        Thread::wait(500); //Wait 1/2 second
    }    
}

void left_thread(void const *args) {
    while (1) {
        leftDist = infraredL * 3.3f;
        Thread::wait(500);     //wait 1/2 second before updating
        }
}

void right_thread(void const *args) {
    while (1) {
        rightDist = infraredR * 3.3f;
        Thread::wait(500);     //wait 1/2 second before updating
        }
}

void front_thread(void const *args) {
    while (1) {
        frontDist = infraredF * 3.3f;
        Thread::wait(500);     //wait 1/2 second before updating
        }
}    

int main() {
    //Test
    Thread left(left_thread);
    Thread right(right_thread);
    Thread front(front_thread);
    
    while(1) {
        
    }
}