arduino base solar tracking system

Required Components: Servo Motor (sg90) Solar panel Arduino Uno LDR’s X 2 (Light Dependent Resistor) 10K resistors X 2 Battery (6 to 12V) How it Works: In this project, LDR’s are working as light detectors. Before we go into detail, we will have to understand how the LDR’s work. LDR (Light Dependent Resistor) also known as photo resistor is the light sensitive device. Its resistance decrease when the light falls on it and that’s why it is frequently used in Dark or Light Detector Circuit. Check the various circuits based on LDR here. The two LDR’s are placed at the two sides of solar panel and the Servo Motor is used to rotate the solar panel. The servo will move the solar panel towards the LDR whose resistance will be low, mean towards the LDR on which light is falling, that way it will keep following the light. And if there is same amount of light falling on both the LDR, then servo will not rotate. The servo will try to move the solar panel in the position where both LDR’s will have the same resistance means where same amount of light will fall on both the resistors and if resistance of one of the LDR will change then it rotates towards lower resistance LDR. Check the Demonstration Video at the end of this Article. Step 1: First of all, take a small piece of cardboard and make a hole at one end. We will insert the screw in it to fix it with the servo later on. Step 2: Now fix two small pieces of cardboard with each other in a V shape with help of glue or hot gun and place solar panel on it. Step 3: Then attach the bottom side of the V shape to the other end of small piece of cardboard in which you made a hole in first step. Step 4: Now insert the screw in the hole you made on card board and insert it through the hole into the servo. The screw comes with the servo motor when you buy it. Step 5: Now place the servo on another piece of cardboard. The size of the cardboard should be larger enough so that you can place a Arduino Uno, a breadboard and a battery on it. Step 6: Attach the LDRs on the two sides of the solar panel with the help of glue. Make sure you have soldered the wires with the legs of the LDR’s. You will have to connect these with the resistors later on. Step 7: Now place the Arduino, battery and the breadboard on the cardboard and make the connection as described in the Circuit diagram and Explanation section below. The final prototype is shown below #include <Servo.h> //including the library of servo motor Servo sg90; //initializing a variable for servo named sg90 int initial_position = 90; //Declaring the initial position at 90 int LDR1 = A0; //Pin at which LDR is connected int LDR2 = A1; //Pin at which LDR is connected int error = 5; //initializing variable for error int servopin=9; void setup() { [login to view URL](servopin); // attaches the servo on pin 9 pinMode(LDR1, INPUT); //Making the LDR pin as input pinMode(LDR2, INPUT); [login to view URL](initial_position); //Move servo at 90 degree delay(2000); // giving a delay of 2 seconds } void loop() { int R1 = analogRead(LDR1); // reading value from LDR 1 int R2 = analogRead(LDR2); // reading value from LDR 2 int diff1= abs(R1 - R2); // Calculating the difference between the LDR's int diff2= abs(R2 - R1); if((diff1 <= error) || (diff2 <= error)) { //if the difference is under the error then do nothing } else { if(R1 > R2) { initial_position = --initial_position; //Move the servo towards 0 degree } if(R1 < R2) { initial_position = ++initial_position; //Move the servo towards 180 degree } } [login to view URL](initial_position); // write the position to servo delay(100); }