4. Embedded Programming

Using the ESP32 board I designed and milled, I controlled the RGB LED on it using a potentiometer.

A potentiometer is a manually adjustable variable resistor with 3 terminals. Two of the terminals are connected to the opposite ends of a resistive element, and the third terminal connects to a sliding contact, called a wiper, moving over the resistive element. To adjust the output voltage the sliding contact gets moved along the resistor on the output side.

Potentiometer Working

Code

const int potPin = 34;  // Analog pin connected to the potentiometer

void setup() {
  Serial.begin(9600);  // Initialize serial communication
}

void loop() {
  int sensorValue = analogRead(potPin);  // Read the potentiometer value
  float voltage = sensorValue * (3.3 / 4095.0);  // Convert ADC value to voltage (assuming 3.3V reference voltage)

  Serial.print("Potentiometer Value: ");
  Serial.print(sensorValue);
  Serial.print(" | Voltage: ");
  Serial.println(voltage, 3);  // Print voltage value with 3 decimal places

  delay(1000);  // Wait for 1 second before reading again
}

Potentiometer + LED

Code

const int potPin = 4;   // Analog pin connected to the potentiometer
const int ledPin = 13;    // PWM pin connected to the LED

void setup() {
  pinMode(ledPin, OUTPUT);   // Set the LED pin as an output
  Serial.begin(9600);        // Initialize serial communication
}

void loop() {
  int sensorValue = analogRead(potPin);  // Read the potentiometer value
  int brightness = map(sensorValue, 0, 4095, 0, 255);  // Map potentiometer value to LED brightness (0-255)

  analogWrite(ledPin, brightness);  // Set the LED brightness

  Serial.print("Potentiometer Value: ");
  Serial.print(sensorValue);
  Serial.print(" | Brightness: ");
  Serial.println(brightness);

  delay(100);  // Delay for stability
}


#include <Adafruit_NeoPixel.h>

#define LED_PIN     38     // Pin connected to the data input of the WS2813 LED
#define POT_PIN     4    // Analog pin connected to the potentiometer

Adafruit_NeoPixel led(1, LED_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  led.begin();
  led.show();  // Initialize LED to 'off'
  Serial.begin(9600);  // Initialize serial communication
}

void loop() {
  int sensorValue = analogRead(POT_PIN);  // Read the potentiometer value
  int brightness = map(sensorValue, 0, 4095, 0, 255);  // Map potentiometer value to LED brightness (0-255)

  led.setBrightness(brightness);  // Set the brightness of the LED

  // Set the color of the LED to red
  led.setPixelColor(0, led.Color(255, 0, 0));
  led.show();  // Update the LED

  Serial.print("Potentiometer Value: ");
  Serial.print(sensorValue);
  Serial.print(" | Brightness: ");
  Serial.println(brightness);

  delay(100);  // Delay for stability
}

Potentiometer + RGB LED WS2813

Code

#include <Adafruit_NeoPixel.h>

#define LED_PIN     38     // Pin connected to the data input of the WS2813 LED
#define POT_PIN     4    // Analog pin connected to the potentiometer

Adafruit_NeoPixel led(1, LED_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  led.begin();
  led.show();  // Initialize LED to 'off'
  Serial.begin(9600);  // Initialize serial communication
}

void loop() {
  int sensorValue = analogRead(POT_PIN);  // Read the potentiometer value

  // Calculate color components based on potentiometer value
  int red, green, blue;
  if (sensorValue < 2048) {
    // Sunset to sunrise transition
    red = map(sensorValue, 0, 2047, 255, 0);  // Red decreases
    green = map(sensorValue, 0, 2047, 150, 0);  // Green decreases
    blue = map(sensorValue, 0, 2047, 0, 255);  // Blue increases
  } else {
    // Sunrise to sunset transition
    red = map(sensorValue, 2048, 4095, 0, 255);  // Red increases
    green = map(sensorValue, 2048, 4095, 0, 150);  // Green increases
    blue = map(sensorValue, 2048, 4095, 255, 0);  // Blue decreases
  }

  // Set the color of the LED
  led.setPixelColor(0, led.Color(red, green, blue));
  led.show();  // Update the LED

  Serial.print("Potentiometer Value: ");
  Serial.print(sensorValue);
  Serial.print(" | Red: ");
  Serial.print(red);
  Serial.print(" | Green: ");
  Serial.print(green);
  Serial.print(" | Blue: ");
  Serial.println(blue);

  delay(100);  // Delay for stability
}