Output Devices Week

For the reminder, I explored Neopixel and speaker so that I can use it in the reminder band.

Neopixel as an Output device

NeoPixels are special LEDs - they're not just one light but three! Each NeoPixel contains tiny red, green, and blue lights all in one package.

Control with SAMD11C14C: The SAMD11C14C microcontroller can control the NeoPixel. By connecting the NeoPixel to one of the microcontroller's pins, we can tell it what to do.

Powering Up: To get the NeoPixel shining, we need to feed it some power. It requires electricity to glow, so I planned to connect to a power source, like the microcontroller's power output. However, I missed out that the board I made last week converts the 5V to 3.3V and I hadnt given provision for 5V, so I soldered a pin to the power source and used a jumper wire to power the new pcb.

Color Control: Inside the NeoPixel, there's a chip that understands commands and adjusts the intensity of the red, green, and blue lights to create any color.

To light up the Neopixel

      #include < Adafruit_NeoPixel.h>

        #define LED_PIN   5  // Define the pin connected to the NeoPixel
        #define LED_COUNT 1  // Define the number of NeoPixels in the chain
        
        Adafruit_NeoPixel strip(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);
        
        void setup() {
          // Initialize NeoPixel strip
          strip.begin();
          strip.show();  // Initialize all pixels to 'off'
        }
        
        void loop() {
          // Set NeoPixel color to green
          strip.setPixelColor(0, 0, 255, 0);  // Green color (R=0, G=255, B=0)
          strip.show();  // Update the NeoPixel strip with the new color
        }

Changing this command, I got red colour. strip.setPixelColor(0, 255, 0, 0);
Changing this command again, I got blue colour. strip.setPixelColor(0, 0, 0, 255);

To colour cycle the neopixel

#include < Adafruit_NeoPixel.h>

  #define LED_PIN     5   // Define the pin connected to the NeoPixel
  #define LED_COUNT   1   // Define the number of NeoPixels in the chain
  
  Adafruit_NeoPixel strip(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);
  
  void setup() {
    // Initialize NeoPixel strip
    strip.begin();
    strip.show();  // Initialize all pixels to 'off'
  }
  
  void loop() {
    colorCycle(10);  // Speed of color cycling (adjust as needed)
  }
  
  // Function to cycle through colors
  void colorCycle(uint8_t wait) {
    uint16_t i;
    
    for(i = 0; i < 256; i++) {
      // Set NeoPixel color
      strip.setPixelColor(0, Wheel((i) & 255));
      strip.show();
      delay(wait);  // Wait between colors
    }
  }
  
  // Input a value 0 to 255 to get a color value
  // The colors are a transition r - g - b - back to r
  uint32_t Wheel(byte WheelPos) {
    if(WheelPos < 85) {
      return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
    } else if(WheelPos < 170) {
      WheelPos -= 85;
      return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
    } else {
      WheelPos -= 170;
      return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
    }
  }

Speaker as an output device

Since I was planning to use a speaker ,it is required to use a trasistor. I used MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). It is a type of transistor commonly used in electronic circuits for switching and amplifying electronic signals. When using a MOSFET with a speaker, it's typically employed as a switch to control the flow of current through the speaker.

This code of Happy birthday is from Alfia's documentation. The link is here.

    #define led 2  // led pin

    #define speakerPin  5
    
    int length = 28;  // the number of notes
    char notes[] = "GGAGcB GGAGdc GGxecBA yyecdc";
    int beats[] = { 2, 2, 8, 8, 8, 16, 1, 2, 2, 8, 8, 8, 16, 1, 2, 2, 8, 8, 8, 8, 16, 1, 2, 2, 8, 8, 8, 16 };
    int tempo = 150;
    
    
    void playTone(int tone, int duration) {
      for (long i = 0; i < duration * 1000L; i += tone * 2) {
        digitalWrite(speakerPin, HIGH);
        delayMicroseconds(tone);
        digitalWrite(speakerPin, LOW);
        delayMicroseconds(tone);
      }
    }
    void playNote(char note, int duration) {
      char names[] = { 'C', 'D', 'E', 'F', 'G', 'A', 'B', 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'x', 'y' };
      int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, 1014, 956, 834, 765, 593, 468, 346, 224, 655, 715 };
      int SPEE = 5;  // play the tone corresponding to the note name
      for (int i = 0; i < 17; i++) {
        if (names[i] == note) {
          int newduration = duration / SPEE;
          playTone(tones[i], newduration);
        }
      }
    }
    
    void setup() {
    
      pinMode(speakerPin, OUTPUT);  //buzzer
      pinMode(led, OUTPUT);
      digitalWrite(led, HIGH);
      delay(1000);
      digitalWrite(led, LOW);
    }
    void loop() {
       for (int i = 0; i < length; i++) {
        if (notes[i] == ' ') {
          delay(beats[i] * tempo);  // rest
        } else {
          playNote(notes[i], beats[i] * tempo);
        }
        // pause between notes
        delay(tempo);
      }
      delay(100);
    }