Analog I/O and PWM

/**
 * Write analog value to a PWM-capable pin
 * Automatically configures pin for PWM output
 * @param pin - PWM-capable pin number (typically 3, 5, 6, 9, 10, 11 on Arduino UNO)
 * @param value - PWM value from 0 (0% duty cycle) to 255 (100% duty cycle)
 * @param callback - Optional callback function called when value is written
 */
analogWrite(pin: number, value: number, callback?: Function): void;

// Set LED to half brightness
arduino.analogWrite(9, 127);

// Fade LED in and out
let brightness = 0;
let direction = 1;

setInterval(function() {
  arduino.analogWrite(9, brightness);

  brightness += direction * 5;
  if (brightness >= 255 || brightness <= 0) {
    direction = -direction;
  }
}, 50);

// Control motor speed (0 = stopped, 255 = full speed)
arduino.analogWrite(6, 200); // ~78% speed

// With callback
arduino.analogWrite(9, 100, function() {
  console.log('PWM value set to 100');
});

/**
 * Read current analog value from an analog input pin
 * @param pin - Analog pin number (0-5 on Arduino UNO, corresponds to A0-A5)
 * @returns Current analog reading as integer from 0 to 1023
 */
analogRead(pin: number): number;

// Read potentiometer on analog pin 0
const potValue = arduino.analogRead(0);
console.log(`Potentiometer reading: ${potValue} (${(potValue/1023*100).toFixed(1)}%)`);

// Read multiple analog sensors
for (let pin = 0; pin < 6; pin++) {
  const reading = arduino.analogRead(pin);
  const voltage = (reading / 1023) * 5.0; // Convert to voltage
  console.log(`A${pin}: ${reading} (${voltage.toFixed(2)}V)`);
}

// Convert reading to percentage
const lightLevel = arduino.analogRead(1);
const lightPercentage = Math.round((lightLevel / 1023) * 100);
console.log(`Light sensor: ${lightPercentage}%`);

// Event: analogChange
// Fired when an analog pin value changes
// Event object properties:
interface AnalogChangeEvent {
  pin: number;     // Analog pin number that changed (0-5)
  value: number;   // New analog reading (0-1023)
  old_value: number; // Previous analog reading
}

arduino.on('analogChange', function(event) {
  console.log(`Analog pin A${event.pin} changed from ${event.old_value} to ${event.value}`);

  // Example: Light sensor trigger
  if (event.pin === 1 && event.value > 800 && event.old_value <= 800) {
    console.log('Bright light detected!');
    arduino.analogWrite(9, 255); // Turn on LED at full brightness
  }

  // Example: Potentiometer controlling LED brightness
  if (event.pin === 0) {
    const brightness = Math.round((event.value / 1023) * 255);
    arduino.analogWrite(9, brightness);
    console.log(`LED brightness set to ${brightness}/255`);
  }
});

const ArduinoFirmata = require('arduino-firmata');
const arduino = new ArduinoFirmata();

arduino.connect();

arduino.on('connect', function() {
  console.log('Arduino connected - Analog I/O ready');

  // Read analog sensors periodically
  setInterval(function() {
    const pot = arduino.analogRead(0);      // Potentiometer
    const light = arduino.analogRead(1);    // Light sensor
    const temp = arduino.analogRead(2);     // Temperature sensor

    console.log(`Sensors - Pot: ${pot}, Light: ${light}, Temp: ${temp}`);

    // Use potentiometer to control LED brightness
    const brightness = Math.round((pot / 1023) * 255);
    arduino.analogWrite(9, brightness);

  }, 1000);

  // Real-time analog monitoring for immediate responses
  arduino.on('analogChange', function(event) {
    // Quick response to light sensor changes
    if (event.pin === 1) {
      if (event.value < 300) { // Dark environment
        arduino.analogWrite(10, 200); // Turn on status LED
      } else { // Bright environment
        arduino.analogWrite(10, 50);  // Dim status LED
      }
    }
  });
});

// Pin modes for analog operations
ArduinoFirmata.ANALOG = 2;  // Analog input mode
ArduinoFirmata.PWM = 3;     // PWM output mode

// Temperature sensor (LM35) - converts reading to Celsius
const tempReading = arduino.analogRead(0);
const voltage = (tempReading * 5.0) / 1024;
const temperature = voltage * 100; // LM35 outputs 10mV per degree C
console.log(`Temperature: ${temperature.toFixed(1)}°C`);

// Control DC motor speed with potentiometer
const speedControl = arduino.analogRead(0);
const motorSpeed = Math.round((speedControl / 1023) * 255);
arduino.analogWrite(9, motorSpeed); // Motor connected to pin 9

// Smooth LED fade effect
let brightness = 0;
let fadeDirection = 1;

setInterval(function() {
  arduino.analogWrite(9, brightness);
  brightness += fadeDirection * 2;

  if (brightness >= 255) {
    fadeDirection = -1;
  } else if (brightness <= 0) {
    fadeDirection = 1;
  }
}, 10);