Circuit Documentation

Summary

The circuit in question is designed to control multiple DC motors and servos using an ESP32 microcontroller. The ESP32 is programmed to handle motor control through a web server interface, allowing for remote operation. The circuit includes motor drivers to manage the power requirements of the DC motors, ultrasonic sensors for distance measurement, and a step-down power converter to regulate the voltage for the servos and sensors. The system is powered by 12V batteries, and a voltage converter is used to step down the voltage to 5V where necessary.

Component List

Microcontroller

• ESP32 (30 pin): A microcontroller with Wi-Fi capabilities, used as the central processing unit of the circuit to control motors, servos, and read sensors.

Motor Drivers

• L298N DC motor driver: Used to drive the DC motors, providing the necessary current and allowing for direction control.

Motors

• DC Motor: Four instances of DC motors are present in the circuit, controlled by the motor drivers.

Servos

• Servo: Four instances of servos are used, likely for precise angular positioning.

Sensors

• HC-SR04 Ultrasonic Sensor: Two instances of ultrasonic sensors for distance measurement.

Power Components

• 12v to 5v Step Down Power Converter: Converts 12V to 5V to power the servos and potentially other 5V components.
• 48v to 5v: Another voltage converter, possibly for additional 5V power requirements.
• battery 12v: Three instances of 12V batteries to provide power to the circuit.

Wiring Details

ESP32 (30 pin)

• D32, D33: Connected to the L298N motor driver for motor control signals.
• D26, D27, D14, D12, D13, D15: Connected to another L298N motor driver for motor control signals.
• GND: Common ground connection with various components including the step-down converter, ultrasonic sensors, motor drivers, and batteries.
• Vin: Power input connected to the 12V battery and step-down converter.
• D23, D22: Connected to the ECHO and TRIG pins of one HC-SR04 ultrasonic sensor.
• D21, D19: Connected to the ECHO and TRIG pins of another HC-SR04 ultrasonic sensor.
• D18, D5, D4, D2: Control pins for the four servos.

L298N DC motor driver

• IN1, IN2, IN3, IN4: Control inputs from the ESP32 for motor direction.
• OUT1, OUT2, OUT3, OUT4: Outputs connected to the DC motors.
• 12V: Power input from the 12V battery.
• GND: Ground connection.

DC Motor

• pin 1, pin 2: Connected to the outputs of the L298N motor drivers.

Servo

• gnd: Ground connection through the step-down converter.
• vcc: Power input from the step-down converter.
• pulse: Control signal from the ESP32.

HC-SR04 Ultrasonic Sensor

• VCC: Power input from the 48v to 5v converter.
• TRIG, ECHO: Control and signal pins connected to the ESP32.
• GND: Ground connection.

12v to 5v Step Down Power Converter

• VIN 9v-36v, VIN+, VIN-: Input from the 12V battery.
• USB OUTPUT 5V, 5v OUTPUT: 5V power output to servos.
• GND: Ground connection.

battery 12v

• +: Positive terminal connected to the ESP32 Vin and motor drivers.
• -: Negative terminal connected to the common ground.

48v to 5v

• out+, out--: 5V output connected to the ultrasonic sensors.
• in+, in--: Input presumably from a higher voltage source.

Documented Code

#include <WiFi.h>
#include <ESPAsyncWebServer.h>
#include <Servo.h>

// Motor pins (L298N Motor Driver)
const int motor1Pin1 = 26;
const int motor1Pin2 = 27;
const int motor2Pin1 = 14;
const int motor2Pin2 = 12;
const int motor3Pin1 = 13;
const int motor3Pin2 = 15;
const int motor4Pin1 = 32;
const int motor4Pin2 = 33;

// Servo pins
Servo servo1;
Servo servo2;
Servo servo3;
Servo servo4;

const int servo1Pin = 2;
const int servo2Pin = 4;
const int servo3Pin = 5;
const int servo4Pin = 18;

// Wi-Fi credentials
const char *ssid = "YOUR_SSID";
const char *password = "YOUR_PASSWORD";

// Server object
AsyncWebServer server(80);

// Function to stop all motors
void stopMotors() {
  digitalWrite(motor1Pin1, LOW);
  digitalWrite(motor1Pin2, LOW);
  digitalWrite(motor2Pin1, LOW);
  digitalWrite(motor2Pin2, LOW);
  digitalWrite(motor3Pin1, LOW);
  digitalWrite(motor3Pin2, LOW);
  digitalWrite(motor4Pin1, LOW);
  digitalWrite(motor4Pin2, LOW);
}

void setup() {
  // Initialize Serial Monitor
  Serial.begin(115200);

  // Setup motor pins
  pinMode(motor1Pin1, OUTPUT);
  pinMode(motor1Pin2, OUTPUT);
  pinMode(motor2Pin1, OUTPUT);
  pinMode(motor2Pin2, OUTPUT);
  pinMode(motor3Pin1, OUTPUT);
  pinMode(motor3Pin2, OUTPUT);
  pinMode(motor4Pin1, OUTPUT);
  pinMode(motor4Pin2, OUTPUT);

  // Attach servos
  servo1.attach(servo1Pin);
  servo2.attach(servo2Pin);
  servo3.attach(servo3Pin);
  servo4.attach(servo4Pin);

  // Connect to Wi-Fi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");

  // Setup web server routes
  server.on("/", HTTP_GET, [](AsyncWebServerRequest *request) {
    request->send(200, "text/plain", "Control your RC Car");
  });

  // Control routes (adjust as per app logic)
  server.on("/forward", HTTP_GET, [](AsyncWebServerRequest *request) {
    digitalWrite(motor1Pin1, HIGH);
    digitalWrite(motor1Pin2, LOW);
    digitalWrite(motor2Pin1, HIGH);
    digitalWrite(motor2Pin2, LOW);
    digitalWrite(motor3Pin1, HIGH);
    digitalWrite(motor3Pin2, LOW);
    digitalWrite(motor4Pin1, HIGH);
    digitalWrite(motor4Pin2, LOW);
    request->send(200, "text/plain", "Moving Forward");
  });

  server.on("/stop", HTTP_GET, [](AsyncWebServerRequest *request) {
    stopMotors();
    request->send(200, "text/plain", "Stopped");
  });

  server.begin();
}

void loop() {
  // Handle other actions like servo movement in response to app commands
}

This code sets up the ESP32 to control the motors and servos via a web server. It defines the pin connections, initializes the components, and provides a basic web interface for controlling the vehicle's movement. The stopMotors function is used to stop all motors, and the setup function configures the Wi-Fi connection and server routes. The loop function is left empty, as the server handles the asynchronous requests.