This may be a long one so bear with me...
What I have is an RFID reader outputting the card data to the serial monitor. Connected to this is a Piezo buzzer capable of different pitches/tones. When I run a card over the reader the buzzer beeps.
Code for this.
This program gets data from the ID12 RFID reader and displays it to the serial monitor
*/
char val = 0; // Value of read from Serial
void setup() {
Serial.begin(9600); // connect to the serial port
} //end of setup
void loop () {
char IDstring[13];
int i;
//if data is available on the serial buffer
if (Serial.available() > 0 ) {
if ( (val = Serial.read()) == 02 ) { // look for Start Of Text marker (i.e ASCII "02")
Serial.print("[SOT] ");
// read until you get End Of Text
for ( i = 0; (val = Serial.read()) != 03 ; i++) {
Serial.print(val, DEC); // Display val in Hexadecimal
Serial.print(" ");
IDstring[i] = val;
}
Serial.println("[EOT]");
Serial.println();
Serial.print(" IDString = ");
IDstring[10] = 0x00; // tie off IDstring at the CR-LF
Serial.print(IDstring);
Serial.println(" ");
Serial.println();
}
}
}//end of loop
Wiring Diagram -
The buzzer is currently in place of the LED. It beeps briefly when any card is ran over it.
What I want to do is have the ID's of different cards corresponding with different notes. An example I found that describes the notes that I want is as follows.
/* Play Melody
* -----------
*
* Program to play a simple melody
*
* Tones are created by quickly pulsing a speaker on and off
* using PWM, to create signature frequencies.
*
* Each note has a frequency, created by varying the period of
* vibration, measured in microseconds. We'll use pulse-width
* modulation (PWM) to create that vibration.
* We calculate the pulse-width to be half the period; we pulse
* the speaker HIGH for 'pulse-width' microseconds, then LOW
* for 'pulse-width' microseconds.
* This pulsing creates a vibration of the desired frequency.
*
* (cleft) 2005 D. Cuartielles for K3
* Refactoring and comments 2006 clay.shirky@nyu.edu
* See NOTES in comments at end for possible improvements
*/
// TONES ==========================================
// Start by defining the relationship between
// note, period, & frequency.
#define c 3830 // 261 Hz
#define d 3400 // 294 Hz
#define e 3038 // 329 Hz
#define f 2864 // 349 Hz
#define g 2550 // 392 Hz
#define a 2272 // 440 Hz
#define b 2028 // 493 Hz
#define C 1912 // 523 Hz
// Define a special note, 'R', to represent a rest
#define R 0
// SETUP ============================================
// Set up speaker on a PWM pin (digital 9, 10 or 11)
int speakerOut = 9;
// Do we want debugging on serial out? 1 for yes, 0 for no
int DEBUG = 1;
void setup() {
pinMode(speakerOut, OUTPUT);
if (DEBUG) {
Serial.begin(9600); // Set serial out if we want debugging
}
}
// MELODY and TIMING =======================================
// melody[] is an array of notes, accompanied by beats[],
// which sets each note's relative length (higher #, longer note)
int melody[] = { C, b, g, C, b, e, R, C, c, g, a, C };
int beats[] = { 16, 16, 16, 8, 8, 16, 32, 16, 16, 16, 8, 8 };
int MAX_COUNT = sizeof(melody) / 2; // Melody length, for looping.
// Set overall tempo
long tempo = 10000;
// Set length of pause between notes
int pause = 1000;
// Loop variable to increase Rest length
int rest_count = 100; //<-BLETCHEROUS HACK; See NOTES
// Initialize core variables
int tone = 0;
int beat = 0;
long duration = 0;
// PLAY TONE ==============================================
// Pulse the speaker to play a tone for a particular duration
void playTone() {
long elapsed_time = 0;
if (tone > 0) { // if this isn't a Rest beat, while the tone has
// played less long than 'duration', pulse speaker HIGH and LOW
while (elapsed_time < duration) {
digitalWrite(speakerOut,HIGH);
delayMicroseconds(tone / 2);
// DOWN
digitalWrite(speakerOut, LOW);
delayMicroseconds(tone / 2);
// Keep track of how long we pulsed
elapsed_time += (tone);
}
}
else { // Rest beat; loop times delay
for (int j = 0; j < rest_count; j++) { // See NOTE on rest_count
delayMicroseconds(duration);
}
}
}
// LET THE WILD RUMPUS BEGIN =============================
void loop() {
// Set up a counter to pull from melody[] and beats[]
for (int i=0; i<MAX_COUNT; i++) {
tone = melody[i];
beat = beats[i];
duration = beat * tempo; // Set up timing
playTone();
// A pause between notes...
delayMicroseconds(pause);
if (DEBUG) { // If debugging, report loop, tone, beat, and duration
Serial.print(i);
Serial.print(":");
Serial.print(beat);
Serial.print(" ");
Serial.print(tone);
Serial.print(" ");
Serial.println(duration);
}
}
}
I left the entire thing there for both credit and clarification as I'm not aiming for anything elaborate such as the entire song playing. Just a single note (from C to C (8 cards)) per card ID.
An example of a card id... IDString = 2500ABD554
The problem I have is that I don't understand what activates the buzzer in the first place, and I don't know how to merge code properly.
Thanks for any help I receive/whoever reads this 
