Circuit Documentation

Summary

This circuit is designed to control a motor using an Arduino Nano and an L298N DC motor driver. The motor is activated based on the light intensity detected by a photocell (LDR). The circuit is powered by a 4 x AAA battery mount. The Arduino Nano reads the light intensity from the LDR and controls the motor driver to turn the motor on or off.

Component List

1. Arduino Nano

   • Description: A small, complete, and breadboard-friendly board based on the ATmega328P.
   • Pins: D1/TX, D0/RX, RESET, GND, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11/MOSI, D12/MISO, VIN, 5V, A7, A6, A5, A4, A3, A2, A1, A0, AREF, 3V3, D13/SCK

2. L298N DC Motor Driver

   • Description: A high voltage, high current dual full-bridge driver designed to accept standard TTL logic levels and drive inductive loads such as relays, solenoids, DC and stepping 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

3. Motor with Reducer

   • Description: A DC motor with a gear reducer to provide higher torque.
   • Pins: 3 - 6 VCC, GND

4. Photocell (LDR)

   • Description: A light-dependent resistor that changes its resistance based on the light intensity.
   • Pins: pin 0, pin 1

5. 4 x AAA Battery Mount

   • Description: A battery holder for four AAA batteries to provide power to the circuit.
   • Pins: -, +

6. Resistor

   • Description: A 1500 Ohms resistor used to limit current.
   • Pins: pin1, pin2
   • Properties: Resistance: 1500 Ohms

Wiring Details

Arduino Nano

• GND is connected to:

  • GND of L298N DC motor driver
  • pin 1 of Photocell (LDR)
  • • of 4 x AAA Battery Mount

• 5V is connected to:

  • pin1 of Resistor
  • 12V of L298N DC motor driver
  • • of 4 x AAA Battery Mount

• A3 is connected to IN2 of L298N DC motor driver

• A2 is connected to IN1 of L298N DC motor driver

• A0 is connected to:

  • pin 0 of Photocell (LDR)
  • pin2 of Resistor

L298N DC Motor Driver

• GND is connected to GND of Arduino Nano

• 12V is connected to:

  • pin1 of Resistor
  • 5V of Arduino Nano
  • • of 4 x AAA Battery Mount

• IN2 is connected to A3 of Arduino Nano

• IN1 is connected to A2 of Arduino Nano

• OUT1 is connected to 3 - 6 VCC of Motor with Reducer

• OUT2 is connected to GND of Motor with Reducer

Motor with Reducer

• 3 - 6 VCC is connected to OUT1 of L298N DC motor driver

• GND is connected to OUT2 of L298N DC motor driver

Photocell (LDR)

• pin 0 is connected to:

  • A0 of Arduino Nano
  • pin2 of Resistor

• pin 1 is connected to:

  • GND of Arduino Nano
  • • of 4 x AAA Battery Mount

4 x AAA Battery Mount

• - is connected to:

  • GND of Arduino Nano
  • pin 1 of Photocell (LDR)

• + is connected to:

  • 5V of Arduino Nano
  • pin1 of Resistor
  • 12V of L298N DC motor driver

Resistor

• pin1 is connected to:

  • 5V of Arduino Nano
  • 12V of L298N DC motor driver
  • • of 4 x AAA Battery Mount

• pin2 is connected to:

  • A0 of Arduino Nano
  • pin 0 of Photocell (LDR)

Code Documentation

int LDR;                     // 儲存光敏電阻的數值
const byte In1 = A2;         // L298N 的 IN1 連接到 NANO 的 A2 腳位
const byte In2 = A3;         // L298N 的 IN2 連接到 NANO 的 A3 腳位

void setup() {
  pinMode(A0, INPUT);        // 設定 A0 為輸入腳位，用來讀取光敏電阻
  pinMode(In1, OUTPUT);      // 設定 In1 為輸出腳位
  pinMode(In2, OUTPUT);      // 設定 In2 為輸出腳位
  Serial.begin(115200);      // 啟動串列監控，便於顯示光敏電阻值
}

void loop() {
  LDR = analogRead(A0);      // 讀取光敏電阻的模擬值，範圍為 0~1023
  Serial.print("LDR = ");
  Serial.println(LDR);       // 輸出 LDR 值到串列監控器

  // 當光線強度低於700（暗處），啟動馬達
  if (LDR < 700) {
    digitalWrite(In1, HIGH); // 設定 In1 為高電位，讓馬達正轉
    digitalWrite(In2, LOW);  // 設定 In2 為低電位，控制馬達方向
    delay(1000);             // 延遲1秒
  } else {
    digitalWrite(In1, LOW);  // 設定 In1 為低電位，停止馬達
    digitalWrite(In2, LOW);  // 設定 In2 為低電位，停止馬達
  }

  delay(500);                // 延遲0.5秒，避免讀取過於頻繁
}

This code reads the light intensity from the LDR and controls the motor based on the light intensity. If the light intensity is below a certain threshold, the motor is turned on; otherwise, it is turned off.