I found a small violin lighter online. Since I have better things to do with my hard-earned money than give big wads of it to Faceless Multinational Corporations and the Government in return for a massively increased risk of an early death, I had an alternative use for it....
Repurpose repurpose repurpose.
Having gutted the lighter mechanism and fuel resovior, and dremmiled off some of the internal supports, I used some double-sided foam tape to stick an Arduino Micro in the case, cutting out a slot in the bottom for the Mini-USB B-port.
I also double-sided-foam-taped an 8-ohm phone speaker on top. Grinding out a little slot in the opposing face of the 'violin' helped the sound get out better. The speaker is connected arross pins 2 and GND.
The little hole at the top where the flame used to come out was perfect for a salvaged push-button switch. The hole even had an aluminium support behind it to keep the switch in place! A 10k-ohm pull-down resistor between ground and Pin-3 and the switch between 5V and Pin-3 complete the circuit. This is a standard switch-sensor as per the Arduino Button Tutorial.
Then it is screwed snugly back together:
Code.
I adapted the arduino example Tone Melody, which also requires the pitches.h file as per the page just linked. I programmed it with the best version I could work out by-ear of "My Heart Bleeds for Thee."
/*
Based on Arduino example 'Melody' by Tom Igoe, 2010-2011
http://www.arduino.cc/en/Tutorial/Tone
This example code is in the public domain.
*/
#include "pitches.h"
// notes in the melody:
int melody[] = {
NOTE_E3, NOTE_C4, NOTE_B3, NOTE_A3, NOTE_G3, NOTE_D3, NOTE_E3,
NOTE_A3, NOTE_D3, NOTE_D3, NOTE_E3, NOTE_D3, NOTE_CS3, NOTE_F3, NOTE_E3
};
// note durations: 4 = quarter note, 8 = eighth note, etc.:
int noteDurations[] = {
4, 4, 2, 8, 4, 4, 2,
8, 8, 8, 8, 4, 4, 2, 2
};
void setup() {
// initialize digital pin 11 as an output.
pinMode(2, OUTPUT); // the speaker
pinMode(3, INPUT); // the button
tone(2, 10000, 100); // go "pip-pip" when power-up complete.
delay(200);
tone(2, 10000, 100);
}
void loop() {
while(digitalRead(3) == 0); // loop until button pressed
// iterate over the notes of the melody:
for (int thisNote = 0; thisNote < 15; thisNote++) {
// to calculate the note duration, take one second
// divided by the note type.
//e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
int noteDuration = 4000 / noteDurations[thisNote];
tone(2, melody[thisNote]*2, noteDuration);
// to distinguish the notes, set a minimum time between them.
int pauseBetweenNotes = noteDuration * 1.0036125;
delay(pauseBetweenNotes);
// stop the tone playing:
noTone(2);
}
delay(400); // slight delay before repeating if the button is being held.
}
