10 Useful Arduino Code Snippets

Here are 10 handy Arduino code snippets for various common tasks:

1. Blink an LED

const int ledPin = 13;

void setup() {
  pinMode(ledPin, OUTPUT);
}

void loop() {
  digitalWrite(ledPin, HIGH);
  delay(1000);  // Wait for 1 second
  digitalWrite(ledPin, LOW);
  delay(1000);  // Wait for 1 second
}

2. Read Analog Input

const int analogPin = A0;

void setup() {
  Serial.begin(9600);
}

void loop() {
  int sensorValue = analogRead(analogPin);
  Serial.println(sensorValue);
  delay(500);
}

3. Button Controlled LED

const int buttonPin = 2;
const int ledPin = 13;

void setup() {
  pinMode(buttonPin, INPUT);
  pinMode(ledPin, OUTPUT);
}

void loop() {
  int buttonState = digitalRead(buttonPin);
  if (buttonState == HIGH) {
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(ledPin, LOW);
  }
}

4. PWM LED Brightness Control

const int ledPin = 9;

void setup() {
  pinMode(ledPin, OUTPUT);
}

void loop() {
  for (int brightness = 0; brightness <= 255; brightness++) {
    analogWrite(ledPin, brightness);
    delay(10);
  }
  for (int brightness = 255; brightness >= 0; brightness--) {
    analogWrite(ledPin, brightness);
    delay(10);
  }
}

5. Temperature Reading with LM35

const int tempPin = A0;

void setup() {
  Serial.begin(9600);
}

void loop() {
  int sensorValue = analogRead(tempPin);
  float voltage = sensorValue * (5.0 / 1023.0);
  float temperature = voltage * 100;  // LM35 outputs 10mV per degree Celsius
  Serial.print("Temperature: ");
  Serial.println(temperature);
  delay(1000);
}

6. Ultrasonic Sensor (HC-SR04) Distance Measurement

const int trigPin = 9;
const int echoPin = 10;

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH);
  int distance = duration * 0.034 / 2;

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  delay(1000);
}

7. Control Servo Motor

#include <Servo.h>

Servo myServo;
const int potPin = A0;

void setup() {
  myServo.attach(9);
}

void loop() {
  int potValue = analogRead(potPin);
  int angle = map(potValue, 0, 1023, 0, 180);
  myServo.write(angle);
  delay(15);
}

8. RGB LED Control

const int redPin = 9;
const int greenPin = 10;
const int bluePin = 11;

void setup() {
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
}

void loop() {
  analogWrite(redPin, 255);   // Full red
  analogWrite(greenPin, 0);
  analogWrite(bluePin, 0);
  delay(1000);

  analogWrite(redPin, 0);
  analogWrite(greenPin, 255);  // Full green
  analogWrite(bluePin, 0);
  delay(1000);

  analogWrite(redPin, 0);
  analogWrite(greenPin, 0);
  analogWrite(bluePin, 255);  // Full blue
  delay(1000);
}

9. Simple Debouncing for Button Input

const int buttonPin = 2;
const int ledPin = 13;
bool lastState = LOW;
bool currentState;
unsigned long lastDebounceTime = 0;
const unsigned long debounceDelay = 50;

void setup() {
  pinMode(buttonPin, INPUT);
  pinMode(ledPin, OUTPUT);
}

void loop() {
  currentState = digitalRead(buttonPin);
  if (currentState != lastState) {
    lastDebounceTime = millis();
  }
  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (currentState == HIGH) {
      digitalWrite(ledPin, !digitalRead(ledPin));
    }
  }
  lastState = currentState;
}

10. OLED Display with SSD1306

#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  if (!display.begin(SSD1306_I2C_ADDRESS, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Hello, OLED!");
  display.display();
}

void loop() {}

These snippets are versatile and can be directly integrated or modified for your projects. Each demonstrates a practical use of Arduino functionalities, from basic GPIO manipulation to interfacing with sensors and displays.