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Thread: LED light on pin 13

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  1. #1
    Junior Member
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    LED light on pin 13

    Forgive my ignorance in electronics. I know (next to) nothing about all this. I have however altered some example code to do what I want it to do. It works great! This is a simple MIDI sketch that uses 5 buttons and a toggle switch to send program changes. When the toggle switch is enabled it changes what program changes are sent.Thus giving me 10 different program changes. I have the on-board led light turning on when I turn on the toggle switch letting me know I'm in the 2nd bank of programs. My question is, do I need some sort of resister when using a regular LED light? I have some left over LEDs from an Arduino UNO kit that I got about a year ago and never used. They have 2 long leads on them. One shorter than the other. Can I just connect the ground and pin 13 to the LED and make this work? I appreciate any help you can give this novice. I'm using a Teensy 3.2. Here is the code I've hobbled together. Thanks.

    /* Simple Teensy DIY USB-MIDI controller.
    Created by Liam Lacey, based on the Teensy USB-MIDI Buttons example code.

    Contains 8 push buttons for sending MIDI messages,
    and a toggle switch for setting whether the buttons
    send note messages or CC messages.

    The toggle switch is connected to input pin 0,
    and the push buttons are connected to input pins 1 - 8.

    You must select MIDI from the "Tools > USB Type" menu for this code to compile.

    To change the name of the USB-MIDI device, edit the STR_PRODUCT define
    in the /Applications/Arduino.app/Contents/Java/hardware/teensy/avr/cores/usb_midi/usb_private.h
    file. You may need to clear your computers cache of MIDI devices for the name change to be applied.

    See https://www.pjrc.com/teensy/td_midi.html for the Teensy MIDI library documentation.

    */
    //The number of push buttons. I've changed this to use just 5 buttons instead of 8.
    //Had to skip pins 2,4 and 6 due to poor soldering skills. lol.

    #include <Bounce.h>
    const int ledPin = 13;
    const int NUM_OF_BUTTONS = 8;
    const int MIDI_CHAN = 10;
    const int DEBOUNCE_TIME = 15;

    Bounce buttons[NUM_OF_BUTTONS + 1] =
    {
    Bounce (0, DEBOUNCE_TIME),
    Bounce (1, DEBOUNCE_TIME),
    Bounce (2, DEBOUNCE_TIME),
    Bounce (3, DEBOUNCE_TIME),
    Bounce (4, DEBOUNCE_TIME),
    Bounce (5, DEBOUNCE_TIME),
    Bounce (6, DEBOUNCE_TIME),
    Bounce (7, DEBOUNCE_TIME),
    Bounce (8, DEBOUNCE_TIME)
    };

    const int MIDI_MODE_ONE = 0;
    const int MIDI_MODE_TWO = 1;

    //Variable that stores the current MIDI mode of the device (what type of messages the push buttons send).
    int midiMode = MIDI_MODE_ONE;

    //Arrays the store the exact note and CC messages each push button will send.
    const int MIDI_ONE_NUMS[NUM_OF_BUTTONS] = {11, 0, 12, 0, 13, 0, 14, 15};
    const int MIDI_ONE_VALS[NUM_OF_BUTTONS] = {127, 127, 127, 127, 127, 127, 127, 127};
    const int MIDI_TWO_NUMS[NUM_OF_BUTTONS] = {1, 0, 2, 0, 3, 0, 4, 5};
    const int MIDI_TWO_VALS[NUM_OF_BUTTONS] = {127, 127, 127, 127, 127, 127, 127, 127};

    //const int MIDI_NOTE_NUMS[NUM_OF_BUTTONS] = {10, 41, 42, 43, 36, 37, 38, 39};
    //const int MIDI_NOTE_VELS[NUM_OF_BUTTONS] = {110, 110, 110, 110, 110, 110, 110, 110};
    //const int MIDI_CC_NUMS[NUM_OF_BUTTONS] = {24, 25, 26, 27, 20, 21, 22, 23};
    //const int MIDI_CC_VALS[NUM_OF_BUTTONS] = {127, 127, 127, 127, 127, 127, 127, 127};

    //================================================== ============================
    //================================================== ============================
    //================================================== ============================
    //The setup function. Called once when the Teensy is turned on or restarted

    void setup()
    {
    // Configure the pins for input mode with pullup resistors.
    // The buttons/switch connect from each pin to ground. When
    // the button is pressed/on, the pin reads LOW because the button
    // shorts it to ground. When released/off, the pin reads HIGH
    // because the pullup resistor connects to +5 volts inside
    // the chip. LOW for "on", and HIGH for "off" may seem
    // backwards, but using the on-chip pullup resistors is very
    // convenient. The scheme is called "active low", and it's
    // very commonly used in electronics... so much that the chip
    // has built-in pullup resistors!
    pinMode(ledPin, OUTPUT);
    for (int i = 0; i < NUM_OF_BUTTONS + 1; i++)
    {
    pinMode (i, INPUT_PULLUP);
    }

    }

    //================================================== ============================
    //================================================== ============================
    //================================================== ============================
    //The loop function. Called over-and-over once the setup function has been called.

    void loop()
    {
    //================================================== ============================
    // Update all the buttons/switch. There should not be any long
    // delays in loop(), so this runs repetitively at a rate
    // faster than the buttons could be pressed and released.
    for (int i = 0; i < NUM_OF_BUTTONS + 1; i++)
    {
    buttons[i].update();
    }

    //================================================== ============================
    // Check the status of each push button

    for (int i = 0; i < NUM_OF_BUTTONS; i++)
    {

    //========================================
    // Check each button for "falling" edge.
    // Falling = high (not pressed - voltage from pullup resistor) to low (pressed - button connects pin to ground)

    if (buttons[i + 1].fallingEdge())
    {
    if (midiMode == MIDI_MODE_ONE)
    usbMIDI.sendProgramChange (MIDI_ONE_NUMS[i], MIDI_CHAN, 0);
    //digitalWrite(ledPin, HIGH); // set the LED on
    //delay(1000); // wait for a second
    //}
    else
    usbMIDI.sendProgramChange (MIDI_TWO_NUMS[i], MIDI_CHAN, 0);
    }

    //========================================
    // Check each button for "rising" edge
    // Rising = low (pressed - button connects pin to ground) to high (not pressed - voltage from pullup resistor)

    } //for (int i = 0; i < NUM_OF_BUTTONS; i++)

    //================================================== ============================
    // Check the status of the toggle switch, and set the MIDI mode based on this.
    if (buttons[0].fallingEdge())
    {
    midiMode = MIDI_MODE_ONE;
    digitalWrite(ledPin, HIGH); // set the LED on
    //delay(200);
    }
    else if (buttons[0].risingEdge())
    {
    midiMode = MIDI_MODE_TWO;
    digitalWrite(ledPin, LOW); // set the LED off
    //delay(200);
    }

    //================================================== ============================
    // MIDI Controllers should discard incoming MIDI messages.
    // http://forum.pjrc.com/threads/24179-...ses-midi-crash
    while (usbMIDI.read())
    {
    // ignoring incoming messages, so don't do anything here.
    }

    }
    Last edited by Gkup; 09-11-2020 at 12:09 AM. Reason: Missing info

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