Circuit Documentation

Summary

This circuit is designed to control a pair of hobby gearmotors and an RGB LED using an ESP32 microcontroller. It also includes a 0.96" OLED display for visual feedback and a 7805 voltage regulator to ensure stable power supply. The circuit is powered by a 4 x AAA battery mount.

Component List

1. Hobby Gearmotor with 48:1 gearbox

   • Pins: pin 1, pin 2
   • Description: A small DC motor with a 48:1 gearbox for increased torque.
   • Purpose: Used for driving the wheels of the robot.

2. 0.96" OLED

   • Pins: GND, VDD, SCK, SDA
   • Description: A small OLED display for visual feedback.
   • Purpose: Displays status messages and other information.

3. RGB LED (Wokwi compatible)

   • Pins: R, COM, G, B
   • Description: An RGB LED for visual indicators.
   • Purpose: Provides visual feedback using different colors.

4. 4 x AAA Battery Mount

   • Pins: -, +
   • Description: Battery holder for four AAA batteries.
   • Purpose: Powers the entire circuit.

5. Ceramic Capacitor

   • Pins: pin0, pin1
   • Description: A capacitor with a capacitance of 0.1 µF.
   • Purpose: Used for filtering and stabilizing the voltage.

6. Resistor (100 Ohms)

   • Pins: pin1, pin2
   • Description: A resistor with a resistance of 100 Ohms.
   • Purpose: Current limiting for the RGB LED.

7. Resistor (47 Ohms)

   • Pins: pin1, pin2
   • Description: A resistor with a resistance of 47 Ohms.
   • Purpose: Current limiting for the RGB LED.

8. 7805 Voltage Regulator

   • Pins: Vin, Gnd, Vout
   • Description: A voltage regulator that outputs 5V.
   • Purpose: Provides a stable 5V supply to the circuit.

9. L9110 Motor Driver

   • Pins: MOTOR B-A, MOTOR B-B, MOTOR A-A, MOTOR A-B, B-IA, B-IB, GND, VCC, A-IA, A-IB
   • Description: A motor driver for controlling two DC motors.
   • Purpose: Drives the hobby gearmotors.

10. Electrolytic Capacitor

    • Pins: -, +
    • Description: A capacitor with a capacitance of 1 µF.
    • Purpose: Used for filtering and stabilizing the voltage.

11. ESP32-WROOM-32UE

    • Pins: 3v3, EN, VP, VN, 34, 35, 32, 33, 25, 26, 27, 14, 12, GND, 13, D2, D3, 5V, 23, 22, TX, RX, 21, 19, 18, 5, 17, 16, 4, 0, 2, 15, D1, D0, CKL
    • Description: A powerful microcontroller with WiFi and Bluetooth capabilities.
    • Purpose: Controls the entire circuit and handles communication.

Wiring Details

Hobby Gearmotor with 48:1 gearbox

• pin 1 connected to L9110 MOTOR B-B
• pin 2 connected to L9110 MOTOR B-A

0.96" OLED

• GND connected to Common Ground
• VDD connected to ESP32 3v3
• SCK connected to ESP32 22
• SDA connected to ESP32 21

RGB LED (Wokwi compatible)

• R connected to Resistor (100 Ohms) pin2
• COM connected to ESP32 3v3
• G connected to Resistor (47 Ohms) pin2
• B connected to Resistor (47 Ohms) pin2

4 x AAA Battery Mount

• - connected to Common Ground
• + connected to 7805 Vin

Ceramic Capacitor

• pin0 connected to 7805 Vin
• pin1 connected to Common Ground

Resistor (100 Ohms)

• pin1 connected to ESP32 12
• pin2 connected to RGB LED R

Resistor (47 Ohms)

• pin1 connected to ESP32 14
• pin2 connected to RGB LED G

Resistor (47 Ohms)

• pin1 connected to ESP32 15
• pin2 connected to RGB LED B

7805 Voltage Regulator

• Vin connected to 4 x AAA Battery Mount +
• Gnd connected to Common Ground
• Vout connected to ESP32 5V

L9110 Motor Driver

• MOTOR B-A connected to Hobby Gearmotor pin 2
• MOTOR B-B connected to Hobby Gearmotor pin 1
• MOTOR A-A connected to Hobby Gearmotor pin 2
• MOTOR A-B connected to Hobby Gearmotor pin 1
• B-IA connected to ESP32 25
• B-IB connected to ESP32 33
• A-IA connected to ESP32 26
• A-IB connected to ESP32 27
• GND connected to Common Ground
• VCC connected to ESP32 5V

Electrolytic Capacitor

• - connected to Common Ground
• + connected to 7805 Vout

ESP32-WROOM-32UE

• 3v3 connected to Common Ground
• GND connected to Common Ground
• 5V connected to 7805 Vout
• 12 connected to Resistor (100 Ohms) pin1
• 14 connected to Resistor (47 Ohms) pin1
• 15 connected to Resistor (47 Ohms) pin1
• 21 connected to 0.96" OLED SDA
• 22 connected to 0.96" OLED SCK
• 25 connected to L9110 B-IA
• 26 connected to L9110 A-IA
• 27 connected to L9110 A-IB
• 33 connected to L9110 B-IB

Code Documentation

#include <WiFi.h>  //remember to download library
#include <Adafruit_SSD1306.h>

// Define pins for RGB LED and motor driver
#define RED_PIN 14
#define GREEN_PIN 12
#define BLUE_PIN 13
#define MOTOR_A1 26
#define MOTOR_A2 27
#define MOTOR_B1 25
#define MOTOR_B2 33
#define OLED_RESET -1

// Create an object for OLED
Adafruit_SSD1306 display(128, 64, &Wire, OLED_RESET);

// WiFi settings
const char* ssid = "Your_SSID";
const char* password = "Your_PASSWORD";

WiFiServer server(80);

void setup() {
  // Initialize RGB LED pins
  pinMode(RED_PIN, OUTPUT);
  pinMode(GREEN_PIN, OUTPUT);
  pinMode(BLUE_PIN, OUTPUT);

  // Initialize OLED
  if (!display.begin(SSD1306_I2C_ADDRESS, 0x3C)) {
    Serial.println(F("OLED initialization failed"));
    for (;;);
  }

  // Initialize serial communication
  Serial.begin(115200);

  // Set motor driver pins as output
  pinMode(MOTOR_A1, OUTPUT);
  pinMode(MOTOR_A2, OUTPUT);
  pinMode(MOTOR_B1, OUTPUT);
  pinMode(MOTOR_B2, OUTPUT);

  // Display "turned on" message and green light
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(10, 25);
  display.println("TURNED ON");
  display.display();
  setRGBColor(0, 255, 0); // Green
  delay(3000);

  // Connect to WiFi
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("Connecting to WiFi...");
  display.display();

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    flashBlue(); // Indicate no connection with flashing blue
    delay(500);
  }

  // Display connected message and set blue light
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(10, 25);
  display.println("CONNECTED");
  display