// Eight pots to MIDI control data
// Code by James Henderson (slightly edited by Sebastian Tomczak)

// command bytes
byte status_byte = 176; // control change on channel 1
byte cc_number = 0; // value for control number

// init transfer and operation values
byte data_send = 0; // stores outgoing byte for spi bus

//to store pot valuse to filter output
byte filter[8];

// init looping and working values
int workPort = 0; // working value for outgoing port
int workAn = 0; // reading from analog in 0

// setup begins here
void setup() {
Serial.begin(31250); // open serial port
pinMode(2,OUTPUT);
pinMode(3,OUTPUT);
pinMode(4,OUTPUT);
}

// main program begins here
void loop() {

for(int i = 0; i < 8; i ++) // loop the following code 8 times
{
cc_number = 20 + i; // set control number to between 20 and 25 depending on loop iteration
PORTD = i << 2; // get pot 1 to 8 ignoring bits 0 and 1 of a 5 bit value
data_send = analogRead(workAn) / 8; //read analog pin into variable... with 10 bit -> 7 bit 


if (filter[i] != data_send){ //if filter and data_send not equal then in theory this will only send midi data when a value is changes an not constantly.
Serial.print(status_byte); // send status byte
Serial.print(cc_number); // send CC number
Serial.print(data_send); // send data value
// loop back...
}

filter[i] = data_send; // Value of filter become same as data_send

// loop back...
}
// loop back...
}