File content as of revision 2:2a4e77f78c8a:

#include "mbed.h"
#include "tca9548a.h"
#include "VL53L0X.h"
#include "LSM9DS1.h"
#define PI 3.14159
#define DECLINATION -4.94

PwmOut PWM(p21);            //Right Side Motor
PwmOut PWM1(p22);           //Left Side Motor
Serial pc(USBTX, USBRX);
TCA9548A i2c_sw(I2C_SDA, I2C_SCL); //default address 0x70 applied
VL53L0X ToF(I2C_SDA, I2C_SCL);
LSM9DS1 IMU(p9, p10, 0xD6, 0x3C);  //imu


float dutyLeft=0.130;
float dutyRight=0.130;
float desHeading = 180.0;
float currentDegreeHeading;
float distanceAway;

float calculateHeading(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;

    pitch *= 180.0 / PI;
    roll  *= 180.0 / PI;

    return heading;
    }


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);
    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;

    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);
}

void calibrateIMU()
{
    IMU.begin();
    if (!IMU.begin()) {
        pc.printf("Failed to communicate with LSM9DS1.\n");
    }
    IMU.calibrate(1);
    IMU.calibrateMag(0);    
    return;
}

void initToF ()
{
    // By default TCA9548A performs a power on reset and all downstream ports are deselected
    for(int i=0;i<4;++i){
        printf(" initializing Tof %d\n",i);
        i2c_sw.select(i);               //  select  the channel 0
        ToF.init(false);
        printf("finished initializing Tof %d\n",i);
        ToF.startContinuous();
        printf("finished starting continous readings for  Tof %d\n",i);
    }
    i2c_sw.select(0);
}

void readToF()
{
        printf("Tof 1:%d mm \t",ToF.readRangeContinuousMillimeters());
        i2c_sw.select(1);
        printf("Tof 2:%d mm \t",ToF.readRangeContinuousMillimeters());
        i2c_sw.select(2);
        printf("Tof 3:%d mm \t",ToF.readRangeContinuousMillimeters());
        i2c_sw.select(3);
         printf("Tof 4:%d mm \n",ToF.readRangeContinuousMillimeters());
        i2c_sw.select(0);
        wait( 0.1 );
}

void readIMU()
{
    while(1){
    while(!IMU.tempAvailable());
        IMU.readTemp();
        while(!IMU.magAvailable(X_AXIS));
        IMU.readMag();
        while(!IMU.accelAvailable());
        IMU.readAccel();
        while(!IMU.gyroAvailable());
        IMU.readGyro();
        //pc.printf("\nIMU Temperature = %f C\n\r",25.0 + IMU.temperature/16.0);
        //pc.printf("        X axis    Y axis    Z axis\n\r");
        //pc.printf("gyro:  %9f %9f %9f in deg/s\n\r", IMU.calcGyro(IMU.gx), IMU.calcGyro(IMU.gy), IMU.calcGyro(IMU.gz));
        //pc.printf("accel: %9f %9f %9f in Gs\n\r", IMU.calcAccel(IMU.ax), IMU.calcAccel(IMU.ay), IMU.calcAccel(IMU.az));
        pc.printf("mag:   %9f %9f %9f in gauss\n\r", IMU.calcMag(IMU.mx), IMU.calcMag(IMU.my), 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));
        //myled = 1;
        wait(0.25);
        //myled = 0;
        wait(0.25);
        }
}

void turnRight()
{
    dutyLeft = 0.18;
    dutyRight = 0.05;              //turn right
    PWM.write(dutyRight);
    PWM1.write(dutyLeft);
    pc.printf("Duty Cycle Left: %f\t Duty Cycle Right: %f\r\n", dutyLeft, dutyRight);
}

void turnLeft()
{
    dutyRight = 0.18;            //increase right motor speed
    dutyLeft = 0.05;              //Stop left motor
    PWM.write(dutyRight);
    PWM1.write(dutyLeft);
    pc.printf("Duty Cycle Left: %f\t Duty Cycle Right: %f\r\n", dutyLeft, dutyRight);
}

void goForward()
{
    if(dutyRight < dutyLeft) {
        dutyLeft = dutyRight;
    }
    if(dutyLeft < dutyRight) {
        dutyRight = dutyLeft;
    }
    dutyRight = 0.18;            
    dutyLeft = 0.18;
    PWM.write(dutyRight);
    PWM1.write(dutyLeft);
    pc.printf("Duty Cycle Left: %f\t Duty Cycle Right: %f\r\n", dutyLeft, dutyRight);
}

void slowDown()
{
    if(dutyRight >=0.130) {
        dutyRight -= 0.001;
    }
    if(dutyLeft >=0.130) {
        dutyLeft -= 0.001;
    }
    PWM.write(dutyRight);
    PWM1.write(dutyLeft);
    pc.printf("Duty Cycle Left: %f\t Duty Cycle Right: %f\r\n", dutyLeft, dutyRight);
}

void stop()
{
    dutyLeft = dutyRight = 0.13;
    PWM.write(dutyRight);
    PWM1.write(dutyLeft);           //stop motor
    pc.printf("Duty Cycle Left: %f\t Duty Cycle Right: %f\r\n", dutyLeft, dutyRight);
}

void steady()
{
    PWM.write(dutyRight);
    PWM1.write(dutyLeft);
}

void startupESC()
{
    PWM.write(0.01);
    PWM1.write(0.01);
    wait(0.5);
    PWM.write(1.0);
    PWM1.write(1.0);
    wait(8);
    PWM.write(0.01);
    PWM1.write(0.01);
    wait(8);
}

void maintainHeading(float desiredHeading){
    while(!IMU.tempAvailable());
    IMU.readTemp();
    while(!IMU.magAvailable(X_AXIS));
    IMU.readMag();
    while(!IMU.accelAvailable());
    IMU.readAccel();
    while(!IMU.gyroAvailable());
    IMU.readGyro();
    currentDegreeHeading = calculateHeading(IMU.calcAccel(IMU.ax), IMU.calcAccel(IMU.ay), IMU.calcAccel(IMU.az), IMU.calcMag(IMU.mx),
                                            IMU.calcMag(IMU.my), IMU.calcMag(IMU.mz));
    pc.printf("heading: %f", currentDegreeHeading);
    currentDegreeHeading = fmod(((double)currentDegreeHeading-desiredHeading),360.0);
    if(currentDegreeHeading<0.0){currentDegreeHeading=360.0-fabs(currentDegreeHeading);}
    pc.printf(" heading: %f\n", currentDegreeHeading);
    
    if(currentDegreeHeading < 180.0 && currentDegreeHeading > 10.0) {
        turnRight();
    } else if(currentDegreeHeading > 180.0 && currentDegreeHeading < 350.0) {
        turnLeft();
    } else {
        goForward();
    }
}

void serialRx(){
    char inp = pc.getc();
    ///// GO FORWARD /////
    if(inp == 'w') {
        //goForward();
        desHeading += 15.0;
    }
    ///// SLOW DOWN /////
    else if(inp == 's') {
        //slowDown();
        desHeading -= 15.0;
    }
    desHeading = fmod(desHeading, 360);
}

void init_motors(){
    PWM.period(0.001);
    PWM1.period(0.001);
    startupESC();
    pc.printf("finished ecs startup");
}
void overall_init(){
    init_motors();
    calibrateIMU();  
    printf("finished imu cal\n"); 
    desHeading = calculateHeading(IMU.calcAccel(IMU.ax), IMU.calcAccel(IMU.ay), IMU.calcAccel(IMU.az), IMU.calcMag(IMU.mx),
                      IMU.calcMag(IMU.my), IMU.calcMag(IMU.mz));
}

void take_input(){
    char inp = pc.getc();
        ///// GO FORWARD /////
        if(inp == 'w' && dutyRight <= 0.230 && dutyLeft <= 0.230) {
            goForward();
        }
        ///// SLOW DOWN /////
        else if(inp == 's') {
            slowDown();
        }
        else if(inp == 't') {
            readToF();
        }
        else if(inp == 'i') {
            //readIMU();
        }
        ///// TURN LEFT /////
        else if(inp == 'a' && dutyRight <= 0.230) {
            turnLeft();
        }
        ///// TURN RIGHT /////
        else if(inp == 'd' && dutyLeft <= 0.230) {
            turnRight();
        }
        ///// STOP /////
        else if(inp == 'x') {
            stop();
        }
        
        ///// STEADY PACE /////
       else {
            
            steady();
        }
}

int main(){
//overall_init();
    initToF();
    calibrateIMU();
    while(1) {
        readToF();
        maintainHeading(desHeading);
        //take_input();        
    }   
}

int backup_main(){
 
}