crankshaft music

things i’m learning from the mp3 trigger that i forgot:
>>power it using usb or 5V? extension
>>Status light:
1 long blink – No formatted microSD media found.
1 long blink, followed by 1 short blink – microSD media found, no MP3 files located.
Constant short blinks – Hardware problem with MP3 Decoder.
3 short blinks – microSD media found, at least 1 MP3 file located.

NAMING
–>Track names have to be as followed:
TRACK001.MP3
TRACK002.MP3

and so on

LIMITATIONS TO THE MP3 FORMAT?
—>IT Supports a bit rate of up to 192 kB

Initially I think my problem is the SD card, if I remember correctly:
What I’m trying to set up now :

–>spin an crank shaft that is somehow attached to an encoder, when the encoder recognizes motion, trigger a song. To trigger a song, this should happen when jumping one of the “mp3 tracks” to ground on the mp3 trigger, ie writing low to one pin that is connected to the mp3 trigger track pins.

using any encoder code: http://bildr.org/2012/08/rotary-encoder-arduino/

and this schematic:http://www.hobbytronics.co.uk/arduino-tutorial6-rotary-encoder

— > Step 1. Only if there is a change in state of encoder position, write LOW to the pin.
Let’s start with pin 13, just to see if I can have this happen with the light.
AND , once the state changing stops, write HIGH (ie don’t play the song)

//code From bildr article: http://bildr.org/2012/08/rotary-encoder-arduino/
// schematic followed from: http://www.hobbytronics.co.uk/arduino-tutorial6-rotary-encoder

//the idea here is that if you start to spin the crankshaft, the encoder will recognize that it is spinning around - 
//and therefore trigger low to an mp3 player pin through arduino's digital pin, thereby 
//acting like a music box that plays a track when you turn a shaft;


//these pins can not be changed 2/3 are special pins (ie have attach - interrupts so arduino no matter WHAT is going on, will not miss it if there is a trigger to D2 or D3)
int encoderPin1 = 2;
int encoderPin2 = 3;

volatile int lastEncoded = 0;
volatile long encoderValue = 0;

long lastEncoderValue = 0;

int lastMSB = 0;
int lastLSB = 0;
const int mp3 = 13;
void setup() {
  Serial.begin (115200);

  pinMode(encoderPin1, INPUT); 
  pinMode(encoderPin2, INPUT);
pinMode(mp3, OUTPUT);

  digitalWrite(encoderPin1, HIGH); //turn pullup resistor on
  digitalWrite(encoderPin2, HIGH); //turn pullup resistor on

  //call updateEncoder() when any high/low changed seen
  //on interrupt 0 (pin 2), or interrupt 1 (pin 3) 
  attachInterrupt(0, updateEncoder, CHANGE); 
  attachInterrupt(1, updateEncoder, CHANGE);
  
  digitalWrite(mp3, HIGH);

}

void loop(){ 
 

//encoderValue = encoderValue/4;
  Serial.print(encoderValue);
   Serial.print("   " );
Serial.println(lastEncoderValue);

if(lastEncoderValue != encoderValue)

{
 digitalWrite(mp3, LOW); 
}
else{digitalWrite(mp3, HIGH);}
 lastEncoderValue = encoderValue;
  delay(1000); //just here to slow down the output, and show it will work  even during a delay
  
}


void updateEncoder(){
  int MSB = digitalRead(encoderPin1); //MSB = most significant bit
  int LSB = digitalRead(encoderPin2); //LSB = least significant bit

  int encoded = (MSB << 1) |LSB; //converting the 2 pin value to single number
  int sum  = (lastEncoded << 2) | encoded; //adding it to the previous encoded value

  if(sum == 0b1101 || sum == 0b0100 || sum == 0b0010 || sum == 0b1011) encoderValue ++;
  if(sum == 0b1110 || sum == 0b0111 || sum == 0b0001 || sum == 0b1000) encoderValue --;

  lastEncoded = encoded; //store this value for next time
}

Simply, this takes an arduino input (ie the encoder) but then outputs a DIGITAL signal to trigger a track. So here, D13 triggers a track to play when written LOW.
The outer strip on the mp3 trigger pins are GND; the inner pins are what D13 should be connected to;

———–
After a while this proved not to be so simple:
https://forum.sparkfun.com/viewtopic.php?f=14&t=32647#p145292
https://forum.sparkfun.com/viewtopic.php?f=14&t=34282#p152976
things learned: use a pull up resistor for triggering clean, LOW output. ; if any of the pins are “pulled high” none of the pins will work…

eventual code:

//code From bildr article: http://bildr.org/2012/08/rotary-encoder-arduino/
// schematic followed from: http://www.hobbytronics.co.uk/arduino-tutorial6-rotary-encoder

//the idea here is that if you start to spin the crankshaft, the encoder will recognize that it is spinning around - 
//and therefore trigger low to an mp3 player pin through arduino's digital pin, thereby 
//acting like a music box that plays a track when you turn a shaft;

//these pins can not be changed 2/3 are special pins (ie have attach - interrupts so arduino no matter WHAT is going on, will not miss it if there is a trigger to D2 or D3)
int encoderPin1 = 2;
int encoderPin2 = 3;

int songState = 1;//1 means the encoder is not turning and the 
// song isn't playing; when the song state changes to 2 , the encoder is turning and the 
//song should be playing through til the end
int prevSongState = 1;//looking at the previous state the song was

int song = 2;//the song int scrolls through in order to change the song from one to the 
//next (a different song int will trigger a different digital output pin)

//digital output pins triggering the MP3 trigger to play
const int trigger1 = 11;
const int trigger2 = 12;
const int trigger3 = 5;

boolean advance = false;//advancing state to the next song

//this is stuff for the encoder reading 
volatile int lastEncoded = 0;
volatile long encoderValue = 0;
long lastEncoderValue = 0;

int lastMSB = 0;
int lastLSB = 0;

//will the song change? not if you are spinning the crank during the song; (counterOFF)
//will the song restart if i keep cranking? yes because they are similar times (15 secs) and the counter is handling that 
unsigned long counterOFF = 100;
unsigned long counter = 100;
int counterChanger = 1;//advances the counter
int counterOFFchanger=1;//advances the counterOFF

void setup() {
  Serial.begin (115200);//open serial port
//initialize the encoder pins
  pinMode(encoderPin1, INPUT); 
  pinMode(encoderPin2, INPUT);
  //initialize the trigger pins
pinMode(trigger1, OUTPUT);
pinMode(trigger2, OUTPUT);
pinMode(trigger3, OUTPUT);

  digitalWrite(encoderPin1, HIGH); //turn pullup resistor on
  digitalWrite(encoderPin2, HIGH); //turn pullup resistor on

  //call updateEncoder() when any high/low changed seen
  //on interrupt 0 (pin 2), or interrupt 1 (pin 3) 
  attachInterrupt(0, updateEncoder, CHANGE); 
  attachInterrupt(1, updateEncoder, CHANGE);
  
  //call the trigger pins high so that they dont start playing the mp3's by accident;
  //default (high) is off
  digitalWrite(trigger1, HIGH);
    digitalWrite(trigger2, HIGH);
    digitalWrite(trigger3, HIGH);

}
void loop(){
  digitalWrite(trigger1, HIGH);
digitalWrite(trigger2, HIGH);
digitalWrite(trigger3, HIGH);

Serial.print(encoderValue);
Serial.print("   " );
Serial.println(lastEncoderValue);
Serial.print("   song  :");
Serial.print(song);

listenToEncoder();

}

void listenToEncoder(){

if(lastEncoderValue != encoderValue && songState ==2 )
  {
    if(counter>15){
     counterOFF=0;
      counter = 0;
  songState = 1; 
    advance = false;
  delay(100);
  Serial.println("spinning the crank");
  if(song ==1){
     delay(100);

    Serial.print("song = ONE");
 digitalWrite(trigger1, LOW); 
  delay(100);
  }
   if(song ==2){
    Serial.print("song = TWO");
     delay(100);
   digitalWrite(trigger2,LOW); 
   delay(100);
  }
  if(song ==3){     
    Serial.print("song = THREE");
     delay(100);
   digitalWrite(trigger3,LOW); 
   delay(100);
  }
  }
  }
else{
songState=2;

digitalWrite(trigger1, HIGH);
digitalWrite(trigger2, HIGH); 
digitalWrite(trigger3, HIGH);
if(counterOFF>19){
  counterOFF = 0;
  
advance  = true;

}
song= getSong();

  }
  counterOFF += counterOFFchanger;
  counter +=counterChanger;
  Serial.println();
  Serial.print("counter:");
Serial.print(counter);
Serial.print("  counterOFF=");
Serial.println(counterOFF);


 Serial.print("   ss= ");
 Serial.print(songState);
 Serial.print("  ");
 lastEncoderValue = encoderValue;
 prevSongState = songState;
  delay(1000); //just here to slow down the output, and show it will work  even during a delay
}

int getSong(){
  if(advance){
    
    Serial.println();
Serial.println("SWITCH"); 
  //advance the song
  song++;
  }
  if(song%3==1||song==0){
 song=1; 
} 
 
    advance = false;
return song;
}


void updateEncoder(){
  int MSB = digitalRead(encoderPin1); //MSB = most significant bit
  int LSB = digitalRead(encoderPin2); //LSB = least significant bit

  int encoded = (MSB << 1) |LSB; //converting the 2 pin value to single number
  int sum  = (lastEncoded << 2) | encoded; //adding it to the previous encoded value

  if(sum == 0b1101 || sum == 0b0100 || sum == 0b0010 || sum == 0b1011) encoderValue ++;
  if(sum == 0b1110 || sum == 0b0111 || sum == 0b0001 || sum == 0b1000) encoderValue --;

  lastEncoded = encoded; //store this value for next time
}