platformio.ini

@@ -12,4 +12,6 @@
 platform = teensy
 board = teensylc
 framework = arduino
+lib_deps = 
+	thomasfredericks/Bounce2@^2.71
 build_flags = -D USB_MIDI -D TEENSY_OPT_FASTEST

src/main.cpp

@@ -1,38 +1,50 @@
 #include <Arduino.h>
+#include <Bounce2.h>
 
 #define MIDI_NAME {'P', 'i', 'n', 'g', 'b', 'o', 'a', 'r', 'd'}
 #define MIDI_NAME_LEN 9
 
-#define KEY_GROUP_NUM 9
+#define CHECK_PINS 9
 #define KEY_PINS 6
-#define NUMBER_OF_KEYS 49
+#define BOUNCE_TIME 5
-
-#define DEBOUNCE_TIMES 2
-
 #define POWER_SUPPLY_CHECK_PIN 13
 
-const uint8_t group_pins[KEY_GROUP_NUM] {14, 15, 16, 17, 18, 19, 20, 21, 22};
+#define NUMBER_OF_KEYS 49
+#define SELF_DRIVE_INTERVAL 100
+
+Bounce check_pins[CHECK_PINS] {
+  {14, BOUNCE_TIME}, // not KEYS1..6
+  {15, BOUNCE_TIME}, // not KEYS7..12
+  {16, BOUNCE_TIME}, // not KEYS13..18
+  {17, BOUNCE_TIME}, // not KEYS19..24
+  {18, BOUNCE_TIME}, // not KEYS25..30
+  {19, BOUNCE_TIME}, // not KEYS31..36
+  {20, BOUNCE_TIME}, // not KEYS37..42
+  {21, BOUNCE_TIME}, // not KEYS43..48
+  {22, BOUNCE_TIME}  // not KEYS49
+};
 
 // not KEY0%6..not KEY5%6
-const uint8_t key_pins[KEY_PINS] {2, 3, 4, 5, 6, 7};
+const unsigned char key_pins[KEY_PINS] {2, 3, 4, 5, 6, 7};
 // Array of pressed keys (initially all 0)
-uint8_t keys_pressed[NUMBER_OF_KEYS];
+bool keys_pressed[NUMBER_OF_KEYS];
 // K1, K2, K3, K4, K5, K12, K13, K14, K15
-const uint8_t self_drive_pins[KEY_GROUP_NUM] {8, 9, 10, 11, 12, 26, 23, 24, 25};
+const unsigned char self_drive_pins[CHECK_PINS] {8, 9, 10, 11, 12, 26, 23, 24, 25};
-uint8_t current_self_drive_pin = 0;
+volatile unsigned char curr_self_drive_pin = 0;
+IntervalTimer self_drive_timer = IntervalTimer();
 
 // Map the current array and pressed key to a MIDI note
-uint8_t mapToMidi(uint8_t active_key_group, uint8_t key) {
+unsigned char mapToMidi(char curr_arr, char key) {
-  uint8_t offset = (active_key_group >> 1) * 12;
+  unsigned char offset = (curr_arr >> 1) * 12;
-  // case 3 and case 4 are swapped on purpose to reflect circuitry
+  // TODO: maybe we have to switch the notes and array offsets
   // Uneven offset are the upper octave, even the lower
-  if (active_key_group & 1) {
+  if (curr_arr & 1) {
     switch (key) {
       case 0: return offset + 42; // F#2 + offset
       case 1: return offset + 43; // G2 + offset
       case 2: return offset + 44; // G#2 + offset
-      case 4: return offset + 45; // A2 + offset
+      case 3: return offset + 45; // A2 + offset
-      case 3: return offset + 46; // A#2 + offset
+      case 4: return offset + 46; // A#2 + offset
       case 5: return offset + 47; // B2 + offset
     }
   } else {
@@ -40,8 +52,8 @@ uint8_t mapToMidi(uint8_t active_key_group, uint8_t key) {
       case 0: return offset + 36; // C2 + offset
       case 1: return offset + 37; // C#2 + offset
       case 2: return offset + 38; // D2 + offset
-      case 4: return offset + 39; // D#2 + offset
+      case 3: return offset + 39; // D#2 + offset
-      case 3: return offset + 40; // E2 + offset
+      case 4: return offset + 40; // E2 + offset
       case 5: return offset + 41; // F2 + offset
     }
   }
@@ -51,19 +63,18 @@ uint8_t mapToMidi(uint8_t active_key_group, uint8_t key) {
 }
 
 // Check if any of the array pins fell since last time
-int8_t getActiveKeyGroup() {
+char findCurrentArrPin() {
-  uint8_t active_groups = 0;
+  for (unsigned char i = 0; i < CHECK_PINS; i++) {
-  int8_t last_active_key_group = -1;
-  for (uint8_t i = 0; i < KEY_GROUP_NUM; i++) {
     // Update status
-    if (digitalReadFast(group_pins[i]) == LOW){
+    check_pins[i].update();
-      last_active_key_group = (int8_t) i;
+    // Check if the pin fell or is low
-      active_groups++;
+    // ! inverted
-    }
+    if (check_pins[i].fell()) return i;
   }
 
-  if (active_groups==1){
+  // If none fell we should have enough time to see which one is low
-    return last_active_key_group;
+  for (unsigned char i = 0; i < CHECK_PINS; i++) {
+    if (check_pins[i].read() == LOW) return i;
   }
 
   // Default return
@@ -73,72 +84,75 @@ int8_t getActiveKeyGroup() {
 // Set the next self drive pin
 FASTRUN void nextSelfDrivePin() {
   // Set the current pin to high
-  digitalWriteFast(self_drive_pins[current_self_drive_pin != 0 ? current_self_drive_pin - 1 : KEY_GROUP_NUM - 1], LOW);
+  digitalWriteFast(self_drive_pins[curr_self_drive_pin], HIGH);
-  digitalWriteFast(self_drive_pins[current_self_drive_pin], HIGH);
   // Set the next pin
-  current_self_drive_pin = (current_self_drive_pin + 1) % KEY_GROUP_NUM;
+  curr_self_drive_pin = (curr_self_drive_pin + 1) % CHECK_PINS;
+}
+
+// Interrupt for power supply check
+FASTRUN void powerStateChanged() {
+  unsigned char state = digitalReadFast(POWER_SUPPLY_CHECK_PIN);
+  // ! inverted
+  if (state == LOW) {
+    curr_self_drive_pin = 0;
+    self_drive_timer.begin(nextSelfDrivePin, SELF_DRIVE_INTERVAL);
+  } else {
+    self_drive_timer.end();
+  }
 }
 
 // Initial start function
 void setup() {
   // Set all in- and outputs
-  for (uint8_t i = 0; i < KEY_GROUP_NUM; i++) {
+  for (unsigned char i = 0; i < CHECK_PINS; i++) {
-    pinMode(group_pins[i], INPUT);
+    pinMode(check_pins[i].getPin(), INPUT);
-    pinMode(self_drive_pins[i], OUTPUT);
+    pinMode(self_drive_pins[i], INPUT);
   }
-  for (uint8_t i = 0; i < KEY_PINS; i++) {
+  for (unsigned char i = 0; i < KEY_PINS; i++) {
     pinMode(key_pins[i], INPUT);
   }
   pinMode(POWER_SUPPLY_CHECK_PIN, INPUT);
+  // Manual call, so we can set the initial state
+  powerStateChanged();
+  // Setup interrupt for power supply
+  attachInterrupt(POWER_SUPPLY_CHECK_PIN, []() { while (true); }, CHANGE);
 }
 
 // Main loop
 void loop() {
   // Find active arr pin
-  int8_t active_key_group = getActiveKeyGroup();  
+  char curr_arr = findCurrentArrPin();  
 
   // If none is active, we do nothing, else we check the keys
-  if (active_key_group >= 0) {
+  if (curr_arr >= 0) {
     // Get all the key values ans send the MIDI message if needed
-    uint8_t value;
+    unsigned char value;
     
-    for (uint8_t i = 0; i < KEY_PINS; i++) {
+    for (unsigned char i = 0; i < KEY_PINS; i++) {
-      // due to the circuitry, there is one phantom note above
-      // the highest key constantly 'playing'
-      // but we don't need to scan that far anyway 
-      if (active_key_group == KEY_GROUP_NUM-1 && i>0){
-        break;
-      }
       value = digitalReadFast(key_pins[i]);
       // If the key is pressed, we send a MIDI message and set the entry in the array
       // ! inverted
       if (value == LOW) { 
         // Check if the key is not already pressed
-        if (keys_pressed[active_key_group * 6 + i] >= DEBOUNCE_TIMES) {
+        if (keys_pressed[curr_arr * 6 + i] == 0) {
           // Send MIDI message
-          usbMIDI.sendNoteOn(mapToMidi(active_key_group, i), 127, 1);
+          usbMIDI.sendNoteOn(mapToMidi(curr_arr, i), 127, 1);
+          // Set the entry in the array
+          keys_pressed[curr_arr * 6 + i] = 1;
         }
-
-        // Set the entry in the array
-        keys_pressed[active_key_group * 6 + i] += keys_pressed[active_key_group * 6 + i] < 0xFF ? 1 : 0;
       } else {
         // Check if the key is not already released
-        if (keys_pressed[active_key_group * 6 + i] < DEBOUNCE_TIMES) {
+        if (keys_pressed[curr_arr * 6 + i] == 1) {
           // Send MIDI message
-          usbMIDI.sendNoteOff(mapToMidi(active_key_group, i), 0, 1);
+          usbMIDI.sendNoteOff(mapToMidi(curr_arr, i), 0, 1);
+          // Set the entry in the array
+          keys_pressed[curr_arr * 6 + i] = 0;
         }
-
-        // Set the entry in the array
-        keys_pressed[active_key_group * 6 + i] = 0;
       }
     }
   }  
 
   // MIDI Controllers should discard incoming MIDI messages.
-  while (usbMIDI.read()) {}
+  while (usbMIDI.read()) {
-
-  // switch to next key group, if self powered
-  if (digitalReadFast(POWER_SUPPLY_CHECK_PIN) == LOW) {
-    nextSelfDrivePin();
   }
 }