Circuit Documentation

Summary

This circuit is designed to control a set of DC motors using an L298N DC motor driver, which is interfaced with an ESP32-CAM MB FLIP microcontroller. The circuit also includes an Arduino UNO connected to an Arduino Expansion Board, which manages a set of servos and LDR (Light Dependent Resistor) photoresistors. The servos are controlled based on the light intensity detected by the LDRs, allowing for light-tracking capabilities. Additionally, the circuit includes inductive proximity sensors for object detection and batteries for power supply.

Component List

• L298N DC Motor Driver: A module used for controlling high current DC motors. It can drive two DC motors simultaneously.
• Arduino UNO: A microcontroller board based on the ATmega328P, used for controlling various components like servos and sensors.
• Arduino Expansion Board: An expansion shield for Arduino UNO, providing easy access to different pins for connecting additional components.
• Servo: A rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity, and acceleration.
• KY-018 LDR Photo Resistor: A light-sensitive device used to detect the intensity of light.
• Motor Amarillo Motorreductor Hobby: A yellow hobby gear motor used for various DIY projects.
• ESP32-CAM MB FLIP: A small camera module with Wi-Fi capabilities, which can be used for surveillance or other camera-related projects.
• Battery 12V: A power source for the motor driver and other components requiring 12V.
• 3.7V Battery: A power source for components requiring lower voltage.
• LJ18A3-H-ZBX Inductive Proximity Sensor: A sensor used to detect the presence of nearby objects without any physical contact.
• Tower Pro SG90 Servo: A small and lightweight servo used for applications where small size and weight are important.

Wiring Details

L298N DC Motor Driver

• OUT1, OUT2: Connected to one set of DC motor terminals.
• OUT3, OUT4: Connected to another set of DC motor terminals.
• 12V: Connected to the positive terminal of the 12V battery.
• GND: Connected to the ground terminal of the 12V battery and ESP32-CAM MB FLIP GND.
• 5V: Connected to ESP32-CAM MB FLIP 5V.
• IN1, IN2, IN3, IN4: Connected to ESP32-CAM MB FLIP IO pins (IO14, IO15, IO13, IO12) for motor control signals.

Arduino UNO

• Reset: Connected to Arduino Expansion Board RST.
• 5V, GND, Vin, A0-A5, AREF, D13-D2: Connected to corresponding pins on the Arduino Expansion Board.
• Unused pins: Not connected.

Arduino Expansion Board

• G, V: Connected to GND and VCC of servos, LDRs, and inductive proximity sensors.
• Digital pins 2-13: Connected to various sensors and actuators as per their control requirements.

Servos

• GND: Connected to the ground (G) on the Arduino Expansion Board.
• VCC: Connected to the voltage supply (V) on the Arduino Expansion Board.
• PWM/Signal: Connected to control pins on the Arduino Expansion Board (e.g., D5, D6, D9).

KY-018 LDR Photo Resistor

• Ground: Connected to the ground (G) on the Arduino Expansion Board.
• VCC: Connected to the voltage supply (V) on the Arduino Expansion Board.
• Signal: Connected to analog input pins on the Arduino Expansion Board (e.g., A0-A3).

Motor Amarillo Motorreductor Hobby

• vcc: Connected to the output pins of the L298N DC motor driver (OUT1, OUT4) and to the positive terminal of the 3.7V battery.
• GND: Connected to the output pins of the L298N DC motor driver (OUT2, OUT3) and to the negative terminal of the 3.7V battery.

ESP32-CAM MB FLIP

• GND: Connected to the ground terminal of the 12V battery.
• 5V: Connected to the 5V output of the L298N DC motor driver.
• IO Pins: Connected to the input pins of the L298N DC motor driver for motor control.

Batteries

• 12V Battery: Provides power to the L298N DC motor driver.
• 3.7V Battery: Provides power to the DC motors.

LJ18A3-H-ZBX Inductive Proximity Sensor

• VO (BLU): Connected to the ground (G) on the Arduino Expansion Board.
• VI (BRN): Connected to the voltage supply (V) on the Arduino Expansion Board.
• SIG (BLK): Connected to digital input pins on the Arduino Expansion Board (e.g., D2, D3).

Documented Code

Arduino UNO Code (sketch.ino)

#include <Servo.h> 

#define SERVOPINH  5 //horizontal servo
#define SERVOPINV  6 //vertical servo

int tol=100;      //The response range of illuminance, the smaller the value, the more sensitive the response, otherwise it is slow 
                  //(the value is 10~100, the sensitivity is different depending on the ambient light intensity, the indoor light source changes greatly, and the change is smaller under the sun)

int dtime=100;    //delay parameter. The smaller the value, the faster the response speed. 
                  //On the contrary, the larger the value, the slower the response speed. Unit: milliseconds General value (10~100) 
            
// Horizontal servo settings
Servo horizontal;            //horizontal servo
int servoh = 90;             //Initialize angle
int servohLimitHigh = 180;   //The maximum angle of rotation in the horizontal direction
int servohLimitLow = 0;      //The minimum angle of rotation in the horizontal direction

// Vertical Servo Settings
Servo vertical;              //vertical servo
int servov = 120;             //Initialize angle
int servovLimitHigh = 180;   //The maximum angle of rotation in the vertical direction
int servovLimitLow = 90;     //The minimum angle of rotation in the vertical direction

// 4 connection ports for photoresistor modules   
const int ldrlt = A0;   //top left
const int ldrrt = A1;   //top right
const int ldrld = A2;   //down left
const int ldrrd = A3;   //down right

void setup()
{
  horizontal.attach(SERVOPINH); 
  vertical.attach(SERVOPINV);
  horizontal.write(servoh);
  vertical.write(servov);
  delay(100);
  Serial.begin(9600);
}

void loop() 
{
  //Read the illuminance values ​​of 4 photoresistor modules respectively
  int lt = analogRead(ldrlt); //upper left
  int rt = analogRead(ldrrt); //top right
  int ld = analogRead(ldrld); //down left
  int rd = analogRead(ldrrd); //down right
  Serial.print("lt:");Serial.print(lt);Serial.print(" ");
  Serial.print("rt:");Serial.print(rt);Serial.print(" ");
  Serial.print("ld:");Serial.print(ld);Serial.print(" ");
  Serial.print("rd:");Serial.println(rd);
  //Average readings from adjacent photoresistor modules    
  int avt = (lt + rt) / 2; 
  int avd = (ld + rd) / 2; 
  int avl = (lt + ld) / 2; 
  int avr = (rt + rd) / 2;

  int veg=(avt + avd + avl + avr) / 4;

 //Adjust response parameters according to different light intensities
 if(0<veg&&veg<300)
 { tol=map(veg,10,300,5,100);
   dtime=map(veg,10,300,100,50);
 }
 else
 { tol=50;
   dtime=50;
 }

  Serial.print("veg= ");Serial.println(veg);
  Serial.print("tol= ");Serial.println(tol);
  Serial.print("dtime= ");Serial.println(dtime);
  

  
  //Then calculate the difference between the upper and lower rows and the average value of the left and right rows
  int dvert = avt - avd;    //upper and lower rows 
  int dhoriz = avl - avr;   //left and right rows

   //Check if the difference is within tolerance, otherwise change the vertical angle    
   if (-1*tol > dvert || dvert > tol) 
   {
      if (avt > avd)
      {
        servov = ++servov;
         if (servov > servovLimitHigh) 
         { 
           servov = servovLimitHigh;
         }
      }
      else if (avt < avd)
      {
        servov= --servov;