Circuit Documentation

Summary

This circuit is designed to control a Wi-Fi-enabled car with a camera using an ESP32-CAM module. The car is powered by a 3.7V battery and uses an L298N motor driver to control four DC motors. Additionally, an MQ-5 gas sensor is included in the circuit for gas detection. The ESP32-CAM module handles the camera functionality and provides a web interface for controlling the car.

Component List

1. L298N DC Motor Driver

   • Description: Motor driver module used to control the DC motors.
   • Pins: OUT1, OUT2, 12V, GND, 5V, OUT3, OUT4, 5V-ENA-JMP-I, 5V-ENA-JMP-O, +5V-J1, +5V-J2, ENA, IN1, IN2, IN3, IN4, ENB

2. ESP32-CAM

   • Description: Microcontroller with built-in camera and Wi-Fi capabilities.
   • Pins: 5V, GND, IO12, IO13, IO15, IO14, IO2, IO4, VOT, VOR, VCC, IO0, IO16, 3V3

3. 3.7V Battery

   • Description: Power source for the circuit.
   • Pins: +, -

4. DC Motor

   • Description: Motor used for driving the car.
   • Pins: pin 1, pin 2

5. MQ-5 Gas Sensor

   • Description: Sensor used for detecting gas.
   • Pins: VCC, GND, Digi Out, Analog out

Wiring Details

L298N DC Motor Driver

• OUT1 is connected to:

  • DC Motor pin 2
  • DC Motor pin 2

• OUT2 is connected to:

  • DC Motor pin 1
  • DC Motor pin 1

• 12V is connected to:

  • 3.7V Battery +

• GND is connected to:

  • MQ-5 Gas Sensor GND
  • ESP32-CAM GND
  • 3.7V Battery -

• 5V is connected to:

  • MQ-5 Gas Sensor VCC
  • ESP32-CAM 5V

• OUT3 is connected to:

  • DC Motor pin 2
  • DC Motor pin 2

• OUT4 is connected to:

  • DC Motor pin 1
  • DC Motor pin 1

• IN1 is connected to:

  • ESP32-CAM IO14

• IN2 is connected to:

  • ESP32-CAM IO15

• IN3 is connected to:

  • ESP32-CAM IO13

• IN4 is connected to:

  • ESP32-CAM IO12

ESP32-CAM

• GND is connected to:

  • L298N DC Motor Driver GND
  • MQ-5 Gas Sensor GND
  • 3.7V Battery -

• 5V is connected to:

  • L298N DC Motor Driver 5V
  • MQ-5 Gas Sensor VCC

• IO14 is connected to:

  • L298N DC Motor Driver IN1

• IO15 is connected to:

  • L298N DC Motor Driver IN2

• IO13 is connected to:

  • L298N DC Motor Driver IN3

• IO12 is connected to:

  • L298N DC Motor Driver IN4

• IO16 is connected to:

  • MQ-5 Gas Sensor Analog out

3.7V Battery

• + is connected to:

  • L298N DC Motor Driver 12V

• - is connected to:

  • L298N DC Motor Driver GND
  • MQ-5 Gas Sensor GND
  • ESP32-CAM GND

DC Motor

• pin 1 is connected to:

  • L298N DC Motor Driver OUT2
  • L298N DC Motor Driver OUT4

• pin 2 is connected to:

  • L298N DC Motor Driver OUT1
  • L298N DC Motor Driver OUT3

MQ-5 Gas Sensor

• VCC is connected to:

  • L298N DC Motor Driver 5V
  • ESP32-CAM 5V

• GND is connected to:

  • L298N DC Motor Driver GND
  • ESP32-CAM GND
  • 3.7V Battery -

• Analog out is connected to:

  • ESP32-CAM IO16

Code Documentation

Main Code

#include "esp_camera.h"
#include <Arduino.h>
#include <WiFi.h>
#include <AsyncTCP.h>
#include <ESPAsyncWebServer.h>
#include <iostream>
#include <sstream>

struct MOTOR_PINS
{
  int pinEn;  
  int pinIN1;
  int pinIN2;    
};

std::vector<MOTOR_PINS> motorPins = 
{
  {12, 13, 15},  //RIGHT_MOTOR Pins (EnA, IN1, IN2)
  {12, 14, 2},  //LEFT_MOTOR  Pins (EnB, IN3, IN4)
};
#define LIGHT_PIN 4

#define UP 1
#define DOWN 2
#define LEFT 3
#define RIGHT 4
#define STOP 0

#define RIGHT_MOTOR 0
#define LEFT_MOTOR 1

#define FORWARD 1
#define BACKWARD -1

const int PWMFreq = 1000; /* 1 KHz */
const int PWMResolution = 8;
const int PWMSpeedChannel = 2;
const int PWMLightChannel = 3;

//Camera related constants
#define PWDN_GPIO_NUM     32
#define RESET_GPIO_NUM    -1
#define XCLK_GPIO_NUM      0
#define SIOD_GPIO_NUM     26
#define SIOC_GPIO_NUM     27
#define Y9_GPIO_NUM       35
#define Y8_GPIO_NUM       34
#define Y7_GPIO_NUM       39
#define Y6_GPIO_NUM       36
#define Y5_GPIO_NUM       21
#define Y4_GPIO_NUM       19
#define Y3_GPIO_NUM       18
#define Y2_GPIO_NUM        5
#define VSYNC_GPIO_NUM    25
#define HREF_GPIO_NUM     23
#define PCLK_GPIO_NUM     22

const char* ssid     = "MyWiFiCar";
const char* password = "12345678";

AsyncWebServer server(80);
AsyncWebSocket wsCamera("/Camera");
AsyncWebSocket wsCarInput("/CarInput");
uint32_t cameraClientId = 0;

const char* htmlHomePage PROGMEM = R"HTMLHOMEPAGE(
<!DOCTYPE html>
<html>
  <head>
  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
    <style>
    .arrows {
      font-size:40px;
      color:red;
    }
    td.button {
      background-color:black;
      border-radius:25%;
      box-shadow: 5px 5px #888888;
    }
    td.button:active {
      transform: translate(5px,5px);
      box-shadow: none; 
    }

    .noselect {
      -webkit-touch-callout: none; /* iOS Safari */
        -webkit-user-select: none; /* Safari */
         -khtml-user-select: none; /* Konqueror HTML */
           -moz-user-select: none; /* Firefox */
            -ms-user-select: none; /* Internet Explorer/Edge */
                user-select: none; /* Non-prefixed version, currently
                                      supported by Chrome and Opera */
    }

    .slidecontainer {
      width: 100%;
    }

    .slider {
      -webkit-appearance: none;
      width: 100%;
      height: 15px;
      border-radius: 5px;
      background: #d3d3d3;
      outline: none;
      opacity: 0.7;
      -webkit-transition: .2s;
      transition: opacity .2s;
    }

    .slider:hover {
      opacity: 1;
    }
  
    .slider::-webkit-slider-thumb {
      -webkit-appearance: none;
      appearance: none;
      width: 25px;
      height: 25px;
      border-radius: 50%;
      background: red;
      cursor: pointer;
    }

    .slider::-moz-range-thumb {
      width: 25px;
      height: 25px;
      border-radius: 50%;
      background: red;
      cursor: pointer;
    }

    </style>
  
  </