Analogue pins not working

Hi all,

I am a complete newbie at Arduino programming, but I have an urgent issue. I have built an electronic xylophone that uses piezo sensors and an Adrunio Mega 2560 to detect when a note is struck and generate a MIDI output. Analogue pins A0-A7 seem to work, but pins A8-A15 do not. All sensors work when plugged into A0-A7. I’m using Hairless serial bridge to transform the serial out into a MIDI output. Hairless recognises input from A0-A7, but not from A8-A15. The code is below. Any help would be appreciated.

int pinRead;
char pinAssignments[16] ={
‘A0’,‘A1’,‘A2’,‘A3’,‘A4’,‘A5’,‘A6’,‘A7’,‘A8’,‘A9’,‘A10’,‘A11’,‘A12’,‘A13’,‘A14’,‘A15’};
byte PadNote[16] = {
57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72}; // MIDI notes from 0 to 127 (Mid C = 60)
int PadCutOff[16] =
{
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100}; // Minimum Analog value to cause a drum hit
int MaxPlayTime[16] = {
90,90,90,90,90,90,90,90,90,90,90,90,90,90,90,90}; // Cycles before a 2nd hit is allowed
#define midichannel 1; // MIDI channel from 0 to 15 (+1 in “real world”)
boolean VelocityFlag = true; // Velocity ON (true) or OFF (false)

//*******************************************************************************************************************
// Internal Use Variables
//*******************************************************************************************************************
boolean activePad[16] = {
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; // Array of flags of pad currently playing
int PinPlayTime[16] = {
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; // Counter since pad started to play
byte status1;

int pin = 0;
int hitavg = 0;
//*******************************************************************************************************************
// Setup
//*******************************************************************************************************************
void setup()
{

Serial.begin(115200);

}
//*******************************************************************************************************************
// Main Program
//*******************************************************************************************************************
void loop()
{
for(int pin=0; pin < 16; pin++) //
{
//int pin = 3;
// for (pinRead=0; pinRead < 16, pin++){
hitavg = analogRead(pinAssignments[pin]);
//Serial.println(hitavg);
// read the input pin

if((hitavg > PadCutOff[pin]))
{
if((activePad[pin] == false))
{
if(VelocityFlag == true)
{
// hitavg = 127 / ((1023 - PadCutOff[pin]) / (hitavg - PadCutOff[pin])); // With full range (Too sensitive ?)
hitavg = (hitavg / 8) -1 ; // Upper range
}
else
{
hitavg = 127;
}
MIDI_TX(144,PadNote[pin],hitavg); //note on

PinPlayTime[pin] = 0;
activePad[pin] = true;
}
else
{
PinPlayTime[pin] = PinPlayTime[pin] + 1;
}
}
else if((activePad[pin] == true))
{
PinPlayTime[pin] = PinPlayTime[pin] + 1;
if(PinPlayTime[pin] > MaxPlayTime[pin])
{
activePad[pin] = false;
MIDI_TX(144,PadNote[pin],0);
}
}
}
}

//*******************************************************************************************************************
// Transmit MIDI Message
//*******************************************************************************************************************
void MIDI_TX(byte MESSAGE, byte PITCH, byte VELOCITY)
{
status1 = MESSAGE + midichannel;
Serial.write(status1);
Serial.write(PITCH);
Serial.write(VELOCITY);

}

Please modify your post, select the code part and press the # button above the smileys. It becomes more readable that way.

Can you tell more about the sensors? - datasheet link?
What voltage do they generate?
Can you tell how you did connect the sensors? do they need a pull up/down resistor?

\

int pinRead;
char pinAssignments[16] ={
  'A0','A1','A2','A3','A4','A5','A6','A7','A8','A9','A10','A11','A12','A13','A14','A15'};
byte PadNote[16] = {
  57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72};         // MIDI notes from 0 to 127 (Mid C = 60)
int PadCutOff[16] = 
{
  100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100};           // Minimum Analog value to cause a drum hit
int MaxPlayTime[16] = {
  90,90,90,90,90,90,90,90,90,90,90,90,90,90,90,90};               // Cycles before a 2nd hit is allowed
#define  midichannel 1;                              // MIDI channel from 0 to 15 (+1 in "real world")
boolean VelocityFlag  = true;                           // Velocity ON (true) or OFF (false)

//*******************************************************************************************************************
// Internal Use Variables
//*******************************************************************************************************************
boolean activePad[16] = {
  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};                   // Array of flags of pad currently playing
int PinPlayTime[16] = {
  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};                     // Counter since pad started to play
byte status1;

int pin = 0;     
int hitavg = 0;
//*******************************************************************************************************************
// Setup
//*******************************************************************************************************************
void setup() 
{
                                 
  Serial.begin(115200);

}
//*******************************************************************************************************************
// Main Program
//*******************************************************************************************************************
void loop() 
{
  for(int pin=0; pin < 16; pin++)                          //
  {
    //int pin = 3;
    //   for (pinRead=0; pinRead < 16, pin++){
    hitavg = analogRead(pinAssignments[pin]);  
    //Serial.println(hitavg);   
    // read the input pin

    if((hitavg > PadCutOff[pin]))
    {
      if((activePad[pin] == false))
      {
        if(VelocityFlag == true)
        {
          //          hitavg = 127 / ((1023 - PadCutOff[pin]) / (hitavg - PadCutOff[pin]));    // With full range (Too sensitive ?)
          hitavg = (hitavg / 8) -1 ;                                                 // Upper range
        }
        else
        {
          hitavg = 127;
        }
        MIDI_TX(144,PadNote[pin],hitavg); //note on

        PinPlayTime[pin] = 0;
        activePad[pin] = true;
      }
      else
      {
        PinPlayTime[pin] = PinPlayTime[pin] + 1;
      }
    }
    else if((activePad[pin] == true))
    {
      PinPlayTime[pin] = PinPlayTime[pin] + 1;
      if(PinPlayTime[pin] > MaxPlayTime[pin])
      {
        activePad[pin] = false;
        MIDI_TX(144,PadNote[pin],0); 
      }
    }
  } 
}

//*******************************************************************************************************************
// Transmit MIDI Message
//*******************************************************************************************************************
void MIDI_TX(byte MESSAGE, byte PITCH, byte VELOCITY) 
{
  status1 = MESSAGE + midichannel;
  Serial.write(status1);
  Serial.write(PITCH);
  Serial.write(VELOCITY);

}

There’s the amended code. The link for the datasheet for the piezo elements is http://octopart.com/datasheet/273-073-radioshack-7529846-11126632

The operating voltage is 30 vp-p. They were connected with 1M ohm 1/4-Watt Carbon Film Resistors.

I’m not sure about this: “char pinAssignments[16] ={ ‘A0’,‘A1’,‘A2’,‘A3’,‘A4’ …”
Could you try without that array.
Just use the integer value 0 to 15 for the analog port.

for(int pin=0; pin < 16; pin++)                          //
  {
    hitavg = analogRead( pin);
    ...

It works! Thank you so much kind stranger!