Musical Greeting Card with EagLED

Difficulty
Moderate
Steps
11

The EagLED comes packed with a number of LEDs and sensors, and can also be used with external components.

In this guide, learn to create a musical greeting card by using the EagLED's light sensor and LED, an external speaker, conductive thread, and felt fabric.

Complete this guide to incorporate sound into your EagLED project.

The parts

In this guide, we'll be creating a musical greeting card with the EagLED! The parts needed:

  • EagLED
    • The main board
    • an LED
    • Light sensor
    • The coin cell battery holder and a CR2032 coin cell battery
  • Alligator clips
    • This will only be used in the prototyping process
  • Small enclosed piezo with wires
  • Sewing needle with large enough eye for easy threading, we recommend one of these.
  • Conductive thread
    • We'll then sew the components using conductive thread
  • Felt fabric and craft paper or cardboard
  • Fabric scissors
  • Soldering iron
  • Solder

Step 1  Prototype

For the heart-shaped LED:

  • Connect the '+' sew tab to '#6' on the EagLED. 
  • Connect its '-' to 'GND' on the EagLED.

For the light sensor:

  • '+' to '3.3V' 
  • '-' to 'GND' 
  • o to '#9'

The coin cell battery holder:

  • '+' to '3.3v'
  • '-' to 'GND'

The piezo buzzer:

  • Red wire to '#3'
  • Black wire to 'GND'

Step 2  Reading the light sensor value


              int ledPin = 6;
int buzzer = 3;
int lightSensor = A9;
int sensorVal = 0;

void setup() {
  pinMode (ledPin, OUTPUT);
  pinMode (lightSensor, INPUT);
  pinMode (buzzer, OUTPUT);
  Serial.begin(9600);
}

void loop() {

  sensorVal = analogRead(lightSensor);
  Serial.println(sensorVal);

}
            
  • Upload this code to your EagLED.
  • Go to Tools > Serial Monitor

With the serial monitor opened up, make sure the baud rate is set to 9600. What do you notice?

The sensor's value increases with the light level while the value will be less as it gets darker. We'll use this value to determine whether the card has been opened.

Step 3  pitches.h


              /*************************************************
 * Public Constants
 *************************************************/

#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 4978
            

Before adding the code needed for the musical greeting card to play a 'happy birthday' melody, add this 'pitches.h' file in a new folder within your 'Arduino' sketches folder. 

Step 4  Arduino sketch


              int ledPin = 6;
int buzzer = 3;
int lightSensor = A9;
int sensorVal = 0;
int threshold = 150;

#include "pitches.h"

//notes in the melody
int melody[] = {
  NOTE_C4, NOTE_C4, NOTE_D4, NOTE_C4, NOTE_F4, NOTE_E4, NOTE_C4, NOTE_C4, NOTE_D4, NOTE_C4, NOTE_G4, NOTE_F4, NOTE_C4, NOTE_C4, NOTE_C5, NOTE_A4, NOTE_F4, NOTE_E4, NOTE_D4, NOTE_AS4, NOTE_AS4, NOTE_A4, NOTE_F4, NOTE_G4, NOTE_F4
};

//note durations: 4 = quarter note, 8 = eight note, etc.
int noteDurations[] = {
  8, 8, 4, 4, 4, 2, 8, 8, 4, 4, 4, 2, 8, 8, 4, 4, 4, 4, 4, 8, 8, 4, 4, 4, 2,
};

void setup() {
  pinMode (ledPin, OUTPUT);
  pinMode (lightSensor, INPUT);
  pinMode (buzzer, OUTPUT);
  Serial.begin(9600);
}

void loop() {

  sensorVal = analogRead(lightSensor);
  Serial.println(sensorVal);
  if (sensorVal > threshold) {
    for (int thisNote = 0 ; thisNote < 25 ; thisNote++) {

      digitalWrite (ledPin, HIGH);
      int noteDuration = 1130 / noteDurations[thisNote];
      tone (buzzer, melody[thisNote], noteDuration);
      int pause = noteDuration * 1.275;
      delay (pause);
      noTone(3);
    }

    delay(1000);
    digitalWrite(ledPin, LOW);

  }
}
            

Now add this Arduino sketch to the same folder where 'pitches.h' is in. 

Open this sketch up again and upload it to the EagLED.

The complete Arduino sketch with the 'pitches.h' file: musical-greeting-card-with-eagled-kit.zip

The LED is connected to '#6' on the EagLED, the speaker is connected to '#3', and the light sensor is connected to analog pin '#9' of the EagLED. When the sensor detects a light level above the set threshold value of '150', (you may want to adjust this value) it will play the tune and the LED will light up. 

Step 5  Making the greeting card

To make the greeting card, a combination of soft and stiff felt fabric was used. You may want to use different materials for yours.

We found felt fabric to be a suitable material for attaching the components with conductive thread.

Step 6  Connect LED to EagLED

  • Stitch a line of conductive thread from '#6' on the EagLED to '+' on the heart shaped LED
  • Next, stitch a line from 'GND' to '-'

Step 7  Connect coin cell battery holder to EagLED

  • Connect '3.3V' on the EagLED to '+' on the coin cell battery holder. 
  • Then stitch a line from 'GND' to '-'
    • Poke the needle through to the back side of the fabric and connect it to a 'GND' tab on the EagLED, making sure that it is not touching another stitched line. This is to prevent any shorts from happening.
    • It can be connected to the same 'GND' tab that the LED is connected to.

Step 8  Connect light sensor to EagLED

  • Connect '3.3V' on the EagLED to '+' on the light sensor.
    • Poke the needle through to the back side of the fabric and connect it to a '3.3V' tab on the EagLED, making sure that it is not touching another stitched line. This is to prevent any shorts from happening.
  • 'GND' to '-'  
  • 'o' to '#9'

Step 9  Connect mini speaker to EagLED

To connect the speaker: 

  • Solder the red wire to '3.3V' on EagLED
  • Solder the black wire to 'GND' on EagLED

Step 10  The complete card

The greeting card will automatically play the "happy birthday" tune when it is opened up. Test it out!