upload source of first version

src/foooot.ino

+
+// some hardware settings
+const int num_buttons = 4;
+int leds[num_buttons] = {12, 11, 10, 9}; // Pin numbers of the LEDs
+int buttons[num_buttons] = {8, 7, 6, 5}; // Pin numbers of the Buttons
+
+// some technical settings
+unsigned long debounce_delay = 50;
+int long_button_time = 700;
+
+// initialize startup values
+int page = 0;
+bool page_set = false;
+
+bool channel[num_buttons * num_buttons];
+bool active_button[num_buttons];
+
+unsigned long button_start[num_buttons];
+unsigned long button_debounce[num_buttons];
+
+
+unsigned long last_led_switch;
+
+void setup() {
+  for (int i = 0; i < num_buttons; i++) {
+    // set everything up
+    // pin modes...
+    pinMode(leds[i], OUTPUT);
+    pinMode(buttons[i], INPUT_PULLUP);
+
+    // button states...
+    button_start[i] = 0;
+    active_button[i] = false;
+
+    // boot signal
+    digitalWrite(leds[i], HIGH);
+  }
+  // Start Midi transmitting
+  Serial.begin(31250);
+
+  // Boot ready
+  delay(1000);
+  for (int i = 0; i < num_buttons; i++) {
+    digitalWrite(leds[i], LOW);
+  }
+}
+
+void loop() {
+  // loop over all buttons
+  for (int i = 0; i < num_buttons; i++) {
+    // read button state
+    int reading = digitalRead(buttons[i]);
+
+    //check if button state changed to active
+    if (reading == LOW && active_button[i] == false && button_start[i] == 0) {
+      // change button state
+      active_button[i] = true;
+      button_start[i] = millis();
+
+    // check if button state is still active
+    } else if (reading == LOW && active_button[i] == true) {
+      // check if its a long press
+      if ((button_start[i] != 0) && (millis() - button_start[i] > long_button_time)) {
+        if (i != page)
+          set_page(i); // change page on long press
+        page_set = true; 
+
+        // LED blink if page is changed
+        if (millis() - last_led_switch > 100) {
+          digitalWrite(leds[i], digitalRead(leds[i]) ? LOW : HIGH);
+          last_led_switch = millis();
+        }
+      }
+    }
+
+    // check if button is released
+    if (reading == HIGH && active_button[i] == true) {
+      active_button[i] = false;
+
+      if (!page_set && (millis() - button_start[i] > debounce_delay)) {
+        toggle_channel(i); // toggle channel only if its not a long press
+      }
+
+      // display current channel state when button is released
+      // this is needed because the LED blinks when the page is changed 
+      if (page_set) {
+        if(channel[page*num_buttons + i]) {
+          digitalWrite(leds[i], HIGH);
+        } else {
+          digitalWrite(leds[i], LOW);
+        }
+      }
+      // reset status stuff
+      button_start[i] = 0;
+      page_set = false;
+    }
+  }
+}
+
+// function to 
+void set_page(int new_page) {
+  page = new_page;
+
+  // update LEDs
+  for (int i = 0; i < num_buttons; i++) {
+    if (channel[page * num_buttons + i]) {
+      digitalWrite(leds[i], HIGH);
+    } else {
+      digitalWrite(leds[i], LOW);
+    }
+  }
+}
+
+void toggle_channel(int i) {
+  int ch = page * num_buttons + i; // calculates channel number
+  digitalWrite(leds[i], channel[ch] ? LOW : HIGH); // update LED
+
+  // Send Midi
+  if(channel[ch]) {
+    channel[ch] = false;
+    Serial.write(byte(176));
+    Serial.write(byte(20+ch));
+    Serial.write(byte(0));
+  } else {
+    channel[ch] = true;
+    Serial.write(byte(176));
+    Serial.write(byte(20+ch));
+    Serial.write(byte(127));
+  }
+}
+