Embedded Files
/*
Allen 182-C Encoder with Three Expression Pedals
==============================================
This sketch is designed to scan a pair of keyboards, the pedal, three expression pedals and 17 pistons for
an Allen 182-C. Unlike the MDC 20 (AllenKeysPedExpScan also available on this website), the 182-C
diodes point away from switches and towards the commone lines making it active LOW while the MDC 20 has it's diodes
reversed and is active HIGH. Active LOW is better suited to the Arduino where, with its built in pull-up resistors,
make this the preferred mode of operation.
Referring to the pin numbers (junction J) on Allen's schematic for this organ, the Swell is scanned by sequentially bringing
pins 15,16,13,14,11,12,9,10,7,8,5 LOW (Arduino pins 20,22,24,26,28,30,32,34,36,38,40)
Pins 35,37,39,41,43,45 (Arduino pins 42,44,46,48,50,52)
are then scanned to determine which keys are closed. LOW = switch closed. Output on Ch. 3
Referring to the pin numbers (junction J) on Allen's schematic for this organ, the Great is scanned by sequentially bringing
pins 28,25,26,23,24,21,22,19,20,17,18 LOW (Arduino pins 21,23,25,27,29,31,33,35,37,39,41)
Pins 35,37,39,41,43,45 (Arduino pins 42,44,46,48,50,52)
are then scanned to determine which keys are closed. LOW = switch closed. Output on Ch. 2
The pins that are scanned for both the swell and the great are the same. These lines are daisy chained between
the two manuals and that connection should remain intact.
Referring to the pin numbers on Allen's schematic for this organ, the Pedal is scanned by sequentially bringing
pins 33,34,31,32,29,30,27 LOW (Arduino pins 54,55,56,57,57,59,60).
Pins 35,37,39,41,43,45 (Arduino pins 43,45,47,49,51,53)
are then scanned to determine which keys are closed. LOW = switch closed. Output on Ch. 1
Note! the wires running to pins 35,37,39,41,43,45 on the pedal are to be detached from the
corresponding pins on the Great and Swell since the pedal has its own set of Arduino pins for the common lines.
Arduino pins 2 - 12, 14 - 19, 61 - 66, are piston inputs. Output on Ch. 4
Pistons are parallel wired and the switches share a common ground to the Arduino.
Arduino Pins 67, 68, 69: are for 3 analog inputs (expression pedals). The controllerArray values will have to be edited to
reflect the voltage range put out by the device. Connect 15k (+/-) pot across Arduino's
5V and Ground. Centre tap goes to pin 67, 68 or 69. Input must never exceed 5V. Output on Ch. 4
Note: ***** Active, but unused analog inputs, must be grounded to avoid spurious control messages *****
Alternatively, the calls to the expression pedal procedures can just be left commented out as in the code below.
Remove the comment (//) in front ot the procedure call in the main loop to activate an input.
Equipment: Arduino Mega with one MIDI shield mounted off the Arduino
Instead of a MIDI shield, two 220 ohm resistors plus a 5-pin DIN MIDI connector can also be used.
created 2024 SEP 06
modified 2024 OCT 04 Expression pedal code added.
by John Coenraads
*/
// Declarations==========================================
//Counters (old Fortran habit)
int i, j, k;
byte noteStatus;
byte noteNumber; // low C = 36
byte noteVelocity;
const byte debounceCount = 4; //Note ON if count reaches decounceCount, OFF if count reaches 0
byte swellDebounceArray [100]; //holds debounce count for each Swell switch
byte greatDebounceArray [100]; //holds debounce count for each Great switch
byte pistonDebounceArray [100]; //holds debounce count for each Piston switch
byte pedalDebounceArray [100]; //holds debounce count for each Piston switch
int oldOldExpression1 = 0, oldExpression1 = 0, newExpression1 = 0; // Expression controller values for expression pedal 1
int oldOldExpression2 = 0, oldExpression2 = 0, newExpression2 = 0; // Expression controller values for expression pedal 2
int oldOldExpression3 = 0, oldExpression3 = 0, newExpression3 = 0; // Expression controller values for expression pedal 3
// The following array represents the controller values output for analog device voltages
// in 0.15V increments ranging from 0 to 5V. Input must never exceed 5V.
// Array can be edited as desired, but must contain exactly 33 entries with values between 0 and 127 only.
byte controllerArray1 [33] = {32,32,32,32,32,32,32,32,32,39,46,54,61,68,76,83,90,97,104,111,119,127,127,127,127,127,127,127,127,127,127,127,127};
byte controllerArray2 [33] = {32,32,32,32,32,32,32,32,32,39,46,54,61,68,76,83,90,97,104,111,119,127,127,127,127,127,127,127,127,127,127,127,127};
byte controllerArray3 [33] = {32,32,32,32,32,32,32,32,32,39,46,54,61,68,76,83,90,97,104,111,119,127,127,127,127,127,127,127,127,127,127,127,127};
//In this example, the potentiometer outputs voltages from 1.35 volts to 3.3 volts.
//The controller values start at 32 to ensure that swell pedal volume does not drop to zero.
//Since 1.35/0.15 = 9, it is with the 10th entry that we start incrementing the controller values e.g., 39,46,54,61 ...
//Since 3.3/0.15 = 22, it is with the 22nd entry that we make sure to reach 127, (the max. value) e.g., ...90,97,104,111,119,127,127
//Even though the voltage range is only 2 volts, this still gives us 13 steps of expression pedal control
//Initialize =========================================================
void setup()
{
// Set MIDI baud rate:
Serial.begin(31250);
//Initialize output (normally high)
for (i = 20; i < 42; i++)
{
pinMode (i, OUTPUT);
digitalWrite (i, HIGH);
}
for (i = 54; i < 61; i++)
{
pinMode (i, OUTPUT);
digitalWrite (i, HIGH);
}
//Initialize input. Normally high (via internal pullups)
for (i = 42; i < 54; i++)
{ pinMode (i, INPUT_PULLUP);}
for (i = 2; i < 13; i++)
{ pinMode (i, INPUT_PULLUP);}
for (i = 14; i < 20; i++)
{ pinMode (i, INPUT_PULLUP);}
for (i = 61; i < 67; i++)
{ pinMode (i, INPUT_PULLUP);}
//Initialize debounce count arrays to zero
for (i= 0; i < 100; i++){
swellDebounceArray[i] = 0;
greatDebounceArray[i] = 0;
pistonDebounceArray[i] = 0;
pedalDebounceArray[i] = 0;
}
}
//Main Loop ===========================================================
void loop()
{
scanSwell();
scanGreat();
scanPistons();
scanPedal();
//scanExpressionPedal1(); // Arduino pin 67
//scanExpressionPedal2(); // Arduino pin 68
//scanExpressionPedal3(); // Arduino pin 69
}
//Scan Swell keyboard, convert to MIDI and output via port 0, channel 3.
void scanSwell ()
{
noteNumber = 36;
digitalWrite (20, LOW);
if (digitalRead(52) == LOW) {turnONswell();} else {turnOFFswell();}
digitalWrite (20, HIGH);
noteNumber++;
for (i = 22; i < 41; i+= 2)
{
digitalWrite (i, LOW);
if (digitalRead(42) == LOW) {turnONswell ();} else {turnOFFswell ();}
noteNumber++;
if (digitalRead(44) == LOW) {turnONswell ();} else {turnOFFswell ();}
noteNumber++;
if (digitalRead(46) == LOW) {turnONswell ();} else {turnOFFswell ();}
noteNumber++;
if (digitalRead(48) == LOW) {turnONswell ();} else {turnOFFswell ();}
noteNumber++;
if (digitalRead(50) == LOW) {turnONswell ();} else {turnOFFswell ();}
noteNumber++;
if (digitalRead(52) == LOW) {turnONswell ();} else {turnOFFswell ();}
digitalWrite (i, HIGH);
noteNumber++;
}
}
//MIDI ON message is sent only if note is not already ON.
void turnONswell ()
{
if (swellDebounceArray[noteNumber] == 0)
{
Serial.write (0x92); //note ON, channel 3
Serial.write (noteNumber);
Serial.write (0x7f); //medium velocity
swellDebounceArray[noteNumber] = debounceCount;
}
}
//MIDI OFF message is sent only if note is not already OFF.
void turnOFFswell ()
{
if (swellDebounceArray[noteNumber] == 1)
{
Serial.write (0x92); //note ON, channel 3
Serial.write (noteNumber);
Serial.write (0); //zero velocity = OFF
}
if (swellDebounceArray[noteNumber] > 0) {swellDebounceArray[noteNumber] -- ;}
}
//*******************************************************************************************
//Scan Great keyboard, convert to MIDI and output via port 0, channel .
void scanGreat ()
{
noteNumber = 36;
digitalWrite (21, LOW);
if (digitalRead(52) == LOW) {turnONgreat();} else {turnOFFgreat();}
digitalWrite (21, HIGH);
noteNumber++;
for (i = 23; i < 42; i+= 2)
{
digitalWrite (i, LOW);
if (digitalRead(42) == LOW) {turnONgreat ();} else {turnOFFgreat ();}
noteNumber++;
if (digitalRead(44) == LOW) {turnONgreat ();} else {turnOFFgreat ();}
noteNumber++;
if (digitalRead(46) == LOW) {turnONgreat ();} else {turnOFFgreat ();}
noteNumber++;
if (digitalRead(48) == LOW) {turnONgreat ();} else {turnOFFgreat ();}
noteNumber++;
if (digitalRead(50) == LOW) {turnONgreat ();} else {turnOFFgreat ();}
noteNumber++;
if (digitalRead(52) == LOW) {turnONgreat ();} else {turnOFFgreat ();}
digitalWrite (i, HIGH);
noteNumber++;
}
}
//MIDI ON message is sent only if note is not already ON.
void turnONgreat ()
{
if (greatDebounceArray[noteNumber] == 0)
{
Serial.write (0x91); //note ON, channel 2
Serial.write (noteNumber);
Serial.write (0x7f); //medium velocity
greatDebounceArray[noteNumber] = debounceCount;
}
}
//MIDI OFF message is sent only if note is not already OFF.
void turnOFFgreat ()
{
if (greatDebounceArray[noteNumber] == 1)
{
Serial.write (0x91); //note ON, channel 2
Serial.write (noteNumber);
Serial.write (0); //zero velocity = OFF
}
if (greatDebounceArray[noteNumber] > 0) {greatDebounceArray[noteNumber] -- ;}
}
//*******************************************************************************************
//Scan pedal keyboard, convert to MIDI and output via port 0, channel 1.
void scanPedal ()
{
noteNumber = 36;
digitalWrite (54, LOW);
if (digitalRead(53) == LOW) {turnONpedal();} else {turnOFFpedal();}
digitalWrite (54, HIGH);
noteNumber++;
for (i = 55; i < 60; i++)
{
digitalWrite (i, LOW);
if (digitalRead(43) == LOW) {turnONpedal ();} else {turnOFFpedal ();}
noteNumber++;
if (digitalRead(45) == LOW) {turnONpedal ();} else {turnOFFpedal ();}
noteNumber++;
if (digitalRead(47) == LOW) {turnONpedal ();} else {turnOFFpedal ();}
noteNumber++;
if (digitalRead(49) == LOW) {turnONpedal ();} else {turnOFFpedal ();}
noteNumber++;
if (digitalRead(51) == LOW) {turnONpedal ();} else {turnOFFpedal ();}
noteNumber++;
if (digitalRead(53) == LOW) {turnONpedal ();} else {turnOFFpedal ();}
digitalWrite (i, HIGH);
noteNumber++;
}
digitalWrite (60, LOW);
if (digitalRead(43) == LOW) {turnONpedal();} else {turnOFFpedal();}
digitalWrite (60, HIGH);
}
//MIDI ON message is sent only if note is not already ON.
void turnONpedal ()
{
if (pedalDebounceArray[noteNumber] == 0)
{
Serial.write (0x90); //note ON, channel 1
Serial.write (noteNumber);
Serial.write (0x7f); //medium velocity
pedalDebounceArray[noteNumber] = debounceCount;
}
}
//MIDI OFF message is sent only if note is not already OFF.
void turnOFFpedal ()
{
if (pedalDebounceArray[noteNumber] == 1)
{
Serial.write (0x90); //note ON, channel 1
Serial.write (noteNumber);
Serial.write (0); //zero velocity = OFF
}
if (pedalDebounceArray[noteNumber] > 0) {pedalDebounceArray[noteNumber] -- ;}
}
//**********************************************************************************************
//Scan Pistons, convert to MIDI and output via port 0, channel 4.
//Piston feed is permanently wired to ground
void scanPistons ()
{
noteNumber = 36;
for (i = 2; i < 13; i++)
{ if (digitalRead(i) == LOW) {turnONpiston ();} else {turnOFFpiston ();}
noteNumber++; }
for (i = 14; i < 20; i++)
{ if (digitalRead(i) == LOW) {turnONpiston ();} else {turnOFFpiston ();}
noteNumber++; }
for (i = 61; i < 67; i++)
{ if (digitalRead(i) == LOW) {turnONpiston ();} else {turnOFFpiston ();}
noteNumber++; }
}
//MIDI ON message is sent only if note is not already ON.
void turnONpiston ()
{
if (pistonDebounceArray[noteNumber] == 0)
{
Serial.write (0x93); //note ON, channel 4
Serial.write (noteNumber);
Serial.write (0x7f); //medium velocity
pistonDebounceArray[noteNumber] = debounceCount;
}
}
//MIDI OFF message is sent only if note is not already OFF.
void turnOFFpiston ()
{
if (pistonDebounceArray[noteNumber] == 1)
{
Serial.write (0x93); //note ON, channel 4
Serial.write (noteNumber);
Serial.write (0); //zero velocity = OFF
}
if (pistonDebounceArray[noteNumber] > 0) {pistonDebounceArray[noteNumber] -- ;}
}
//Expression pedal input:
//Voltage inputs from 0 to 5V are converted to a 10 bit integer from 0 to 1023 by analog to digital converter.
//Adding 1 and dividing by 32, yields an integer from 0 to 32. This is used as an index into the controllerArray
//to select the controller value to be output.
void scanExpressionPedal1()
{
newExpression1 = analogRead (67); //0 to 1023
newExpression1 = (newExpression1 + 1) / 32; //0 to 32
if ((newExpression1 != oldExpression1) && (newExpression1 != oldOldExpression1)) // double check avoids jitter
{
oldOldExpression1 = oldExpression1;
oldExpression1 = newExpression1;
newExpression1 = controllerArray1 [newExpression1]; //extract controller value from array
if (newExpression1 > 127)
{
newExpression1 = 127; //correct out of range controller value
}
Serial.write (0xB3); //controller (channel 4)
Serial.write (0); //control number 1
Serial.write (newExpression1);
}
}
void scanExpressionPedal2()
{
newExpression2 = analogRead (68); //0 to 1023
newExpression2 = (newExpression2 + 1) / 32; //0 to 32
if ((newExpression2 != oldExpression2) && (newExpression2 != oldOldExpression2)) // double check avoids jitter
{
oldOldExpression2 = oldExpression2;
oldExpression2 = newExpression2;
newExpression2 = controllerArray2 [newExpression2]; //extract controller value from array
if (newExpression2 > 127)
{
newExpression2 = 127; //correct out of range controller value
}
Serial.write (0xB3); //controller (channel 1)
Serial.write (1); //control number 2
Serial.write (newExpression2);
}
}
void scanExpressionPedal3()
{
newExpression3 = analogRead (69); //0 to 1023
newExpression3 = (newExpression3 + 1) / 32; //0 to 32
if ((newExpression3 != oldExpression3) && (newExpression3 != oldOldExpression3)) // double check avoids jitter
{
oldOldExpression3 = oldExpression3;
oldExpression3 = newExpression3;
newExpression3 = controllerArray3 [newExpression3]; //extract controller value from array
if (newExpression3 > 127)
{
newExpression3 = 127; //correct out of range controller value
}
Serial.write (0xB3); //controller (channel 4)
Serial.write (2); //control number 3
Serial.write (newExpression3);
}
}
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