Help with a sample code of sun tracking with Arduino Uno

[Bojan Andonovski]

Hi

I have Pololu High-Power 18V 15A motor driver, Arduino Uno microcontroler, 12V DC worm gear Motor and light sensor module. Im building a prototype for tracking a solar panel. So , from example in the morning the panels are in their initial (home, horizontal position) and start tracking the sun and motor start moving. I include the code but when testing the motor is moving always when light is bigger than upper thresh. Which is not correct as I wont that motor stop moving and panel stops when sun reach its maximum and at the end of the day panel comes back (motor runs in other direction).

Include the sample code. So what Im missing here?

/*
WIRING INSTRUCTION: includes 1 motor  (hinge motor) and 1 sensor.




pin 8: hinge motor direction pin
pin 11: hinge motor speed pin (PWM)
sensor 1 pin a: pin A0

*/
#include <TimerOne.h>
#include <avr/sleep.h>
#include <avr/power.h>
#include <avr/wdt.h>
#include <SPI.h>
#include <Wire.h>



#define BRAKE1 12
#define BRAKE2 7

#define sensor1 A0  //Purple cable
#define motor_speed 750  //default motor speed @ 0.3rpm
#define array_size 30  //10 samples




volatile long data1 = 0;
volatile int check_counter = 0;
volatile int execute_counter = 0;
volatile int motor_time_counter = 0;
volatile byte check_flag = 0;
volatile byte time_out_flag = 0;
volatile byte motor_time_flag = 0;

char upperthres = 40;  //CW tolerance, upper threshold
char lowerthres = 17;  //CCW tolerance, lower threshold
int sensor1_data_hinge[array_size];
int planned_motor1 = 0;  //Planned motion: 0-no rotation; 1-CW; 2-CCW
int lightLevel;


/* SENSOR PROCESSING */
int readSensor1()
{
  //  interrupts();
  int avg = 0;
  /*SHIFT DATA*/
  for (int i = 0; i < array_size; i++)
  {
    avg = avg + sensor1_data_hinge;
    sensor1_data_hinge = sensor1_data_hinge[i+1];
  }

  /*ACCEPT NEW READING*/
  sensor1_data_hinge[array_size-1] = analogRead(sensor1);
  avg = avg/array_size;

  // noInterrupts();
  return avg;
}

///

/*MOTOR CONTROL*/

void hingeCW ()    //turn RIGHT
{
  digitalWrite(8, HIGH);  //set direction for hinge motor
  analogWrite(11, motor_speed);   //set speed for hinge motor
}

void hingeCCW ()    //turn LEFT
{
  digitalWrite(8, LOW);  //set direction for hinge motor
  analogWrite(11, motor_speed);  //set speed for hinge motor
}

void stopHingeMotor ()
{
  analogWrite(11, 0);  //set 0 speed for hinge motor
}

//-------------MOTOR 1 Operations-------------
void check_motor1()
{
  //read sensor
  data1 = readSensor1();
  //plan which movement to take
  if (data1 >= upperthres)
  {
    planned_motor1 = 1;
  }

  else if (data1 <= lowerthres)
  {
    planned_motor1 = 2;
  }
  else planned_motor1 = 0;
}

//wait for a bit
//delay(2000);  //MAYBE SPLIT THE PROCEDURE INTO 2 PHASES: CHECKING AND EXECUTING


void execute_motor1()
{
  //read sensor again
  data1 = readSensor1();
  //check if planned movement is still correct after waiting
  if (data1 >= upperthres && planned_motor1 == 1)
  {
    //enable motor timer
    motor_time_flag = 1;
    hingeCW();
    //continually check sensor and count down to stop motor
    while (data1 >= upperthres && time_out_flag == 0)
    {
      data1 = readSensor1();
    }
    motor_time_counter = 0;
    motor_time_flag = 0;
    time_out_flag = 0;
    stopHingeMotor();
  }
  else if (data1 <= lowerthres && planned_motor1 == 2)
  {
    //enable motor timer
    motor_time_flag = 1;
    hingeCCW();
    //continually check sensor and count down to stop motor
    while (data1 <= lowerthres && time_out_flag == 0)
    {
      data1 = readSensor1();
    }

    //reset timer  parameters incase the loop exits because hinge reaches correct position
    motor_time_counter = 0;
    motor_time_flag = 0;
    time_out_flag = 0;
    stopHingeMotor();
  }

  //if planned movement does not match, reset everything
  else planned_motor1 = 0;
}


/*END OF MOTOR CONTROL*/

ISR(WDT_vect)
{
  check_counter++;
  if (check_counter == 2)
  {
    check_counter = 0;
    check_flag = 1;
  }
}

void timerIsr()
{
  if (motor_time_flag == 1)
  {
    motor_time_counter++;
    //Motor rotation time out parameter
    if (motor_time_counter == 45)  //15 ~ 1 second
    {
      motor_time_counter = 0;
      motor_time_flag = 0;
      time_out_flag = 1;
    }
  }
}

void enterSleep(void)
{
 set_sleep_mode(SLEEP_MODE_PWR_DOWN);   /* EDIT: could also use SLEEP_MODE_PWR_DOWN for lowest power consumption. */
  sleep_enable();

  /* Now enter sleep mode. */
  sleep_mode();

  /* The program will continue from here after the WDT timeout*/
  sleep_disable(); /* First thing to do is disable sleep. */

  /* Re-enable the peripherals. */
  power_all_enable();
}


void setup()
{
  pinMode(8, OUTPUT);         //hinge direction pin
  pinMode(11, OUTPUT);         //hinge speed pin
  Serial.begin (9600);

  Timer1.initialize(100000);              // 100000 = 100ms
  Timer1.attachInterrupt( timerIsr );

  MCUSR &= ~(1<<WDRF);

  /* In order to change WDE or the prescaler, we need to
   * set WDCE (This will allow updates for 4 clock cycles).
   */
  WDTCSR |= (1<<WDCE) | (1<<WDE);

  /* set new watchdog timeout prescaler value */
  WDTCSR = 1<<WDP0 | 1<<WDP3; /* 8.0 seconds */

  /* Enable the WD interrupt (note no reset). */
  WDTCSR |= _BV(WDIE);

  //initiate sensor data
  for (int i = 0; i < 20; i++)
  {
    data1 = readSensor1();
  }
}

void loop()
{
  if (check_flag == 1 && (analogRead(sensor1) >= 5))
  {
    //=====Track hinge======
    check_motor1();
    delay(200);
    execute_motor1();
  }
  lightLevel = analogRead(A0);
  Serial.println(lightLevel, DEC);
  //Serial.println("sleep active");
  Serial.println("sleep active");
  delay(50);
  enterSleep();
  Serial.println("wake up");
  //execute_motor1();
  delay(50);
}

 

[Harald Kapp]

Welcome to electronicspoint. I took the liberty to clean up your post a tiny bit by putting the sample code in a code box.

 

[Bojan Andonovski]

thanks

 

[Harald Kapp]

First, this bit of code looks suspicious:

  for (int i = 0; i < array_size; i++)
  {
    avg = avg + sensor1_data_hinge;
    sensor1_data_hinge = sensor1_data_hinge[i+1];
  }

• sensor1_data_hinge is an array, therefore "sensor1_data_hinge" is an adddress but you surely do not want to add an address to the average value.
• Also since "sensor1_data_hinge" is an adddress, the assignment "sensor1_data_hinge = sensor1_data_hinge[i+1];" will try to change the address, not the value as expected.
• for i==(array_size-1), the last value for i within the for loop, "sensor1_data_hinge[i+1]" is an invalid reference since the index [i+1] lies outside the array boundaries [0...array-size-1].

I suggest the following changes:

  for (int i = 0; i < array_size; i++)
  {
    avg = avg + sensor1_data_hinge[i];
    if (i < (array_size-1))
        sensor1_data_hinge[i] = sensor1_data_hinge[i+1];
  }

There may be more similar issues, this is just the first I came across.

As a note on the side: imho it is good practice to use capital letters for defines to discern them clearly from variables. Therefore I suggest you write

#define SENSOR1 A0  //Purple cable
#define MOTOR_SPEED 750  //default motor speed @ 0.3rpm
#define ARRAY_SIZE 30  //10 samples

etc. for bettter clarity. This will have no influence on the compiled code, however.

 

[Bojan Andonovski]

thanks. But that code was already in my original version. I dont understand why now after your changers appears different

 

[BobK]

The square brackets were interpreted as bb-code commands.

Bob