Documentation

// Blink the onboard yellow LED wired to D13.
// The classic "Hello World" of microcontrollers.

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);   // LED_BUILTIN = D13 on the Nano
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
}

// Print a counter over USB serial.
// Open Serial Monitor at 9600 baud to see output.

unsigned long counter = 0;

void setup() {
  Serial.begin(9600);
  Serial.println("Arduino Nano V3.0 ready!");
}

void loop() {
  Serial.print("Counter: ");
  Serial.println(counter);
  counter++;
  delay(500);
}

// Scan the I2C bus and print the address of every device.
// Use SDA = A4 and SCL = A5 on the Nano.

#include <Wire.h>

void setup() {
  Wire.begin();
  Serial.begin(9600);
  Serial.println("I2C Scanner");
}

void loop() {
  byte error, address;
  int nDevices = 0;

  Serial.println("Scanning...");

  for (address = 1; address < 127; address++) {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0) {
      Serial.print("I2C device found at 0x");
      if (address < 16) Serial.print("0");
      Serial.println(address, HEX);
      nDevices++;
    }
  }

  if (nDevices == 0) Serial.println("No I2C devices found");
  else { Serial.print(nDevices); Serial.println(" device(s) found"); }

  delay(5000);
}

// Read an analog value from A0 (potentiometer, LDR, etc.)
// and print both the raw 10-bit value (0-1023) and the voltage.

const int SENSOR_PIN = A0;

void setup() {
  Serial.begin(9600);
  Serial.println("Analog Read on A0");
}

void loop() {
  int rawValue = analogRead(SENSOR_PIN);
  float voltage = rawValue * (5.0 / 1023.0);

  Serial.print("Raw: ");
  Serial.print(rawValue);
  Serial.print("  Voltage: ");
  Serial.print(voltage, 3);
  Serial.println(" V");

  delay(200);
}

// Fade an LED in and out using PWM.
// Wire an LED (with a 220 ohm resistor) from D9 to GND.
// D9 is one of six PWM pins (marked with "~" on the silkscreen).

const int LED_PIN = 9;
int brightness = 0;
int fadeStep = 5;

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

void loop() {
  analogWrite(LED_PIN, brightness);

  brightness += fadeStep;
  if (brightness <= 0 || brightness >= 255) {
    fadeStep = -fadeStep;  // Reverse direction at endpoints
  }

  delay(20);
}