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Thread: Teensy 4.0 with multiple encoders and analogue input

  1. #1
    Junior Member
    Join Date
    Jul 2021

    Teensy 4.0 with multiple encoders and analogue input

    Hi all,

    Very new to the Teensy world and looking for some advise and perhaps a guide in the right direction. Sorry if my terminology is not correct.

    I am building a gaming Sim Wheel. I am wanting to run 11 encoders in which they would make adjustments to in car controls in a sim game. Basically an up and down button i guess you might say.
    Encoders are connected as code below with all centre pins daisy chained to ground

    I have uploaded the Teensy/ encoder/ twoknobs example and have edited it to show my 11 encoders. With the serial monitor i can see all encoders and make them count up and down however when rotated i get the odd jump in my steps (count)?

    I am also lost as to how to add an analogue input which i would use a potentiometer as a paddle clutch.

    The other issue i have is that this doesnt make the teensy a windows USB game device.

    As i said i am very new to this and just looking for some assistance please.

    Code i am using follows -

    ************************************************** *****************************************

    #include <Encoder.h>

    // Change these pin numbers to the pins connected to your encoder.
    // Best Performance: both pins have interrupt capability
    // Good Performance: only the first pin has interrupt capability
    // Low Performance: neither pin has interrupt capability
    Encoder encoder1(0, 1);
    Encoder encoder2(2, 3);
    Encoder encoder3(4, 5);
    Encoder encoder4(6, 7);
    Encoder encoder5(8, 9);
    Encoder encoder6(10, 11);
    Encoder encoder7(12, 14);
    Encoder encoder8(15, 16);
    Encoder encoder9(17, 18);
    Encoder encoder10(19, 20);
    Encoder encoder11(21, 22);

    // avoid using pins with LEDs attached

    void setup() {
    Serial.println("Encoder Clutch:");

    long position1 = -999;
    long position2 = -999;
    long position3 = -999;
    long position4 = -999;
    long position5 = -999;
    long position6 = -999;
    long position7 = -999;
    long position8 = -999;
    long position9 = -999;
    long position10 = -999;
    long position11 = -999;

    void loop() {
    long enc1, enc2, enc3, enc4, enc5, enc6, enc7, enc8, enc9, enc10, enc11;
    enc1 =;
    enc2 =;
    enc3 =;
    enc4 =;
    enc5 =;
    enc6 =;
    enc7 =;
    enc8 =;
    enc9 =;
    enc10 =;
    enc11 =;

    if (enc1 != position1 || enc2 != position2 || enc3 !=position3 || enc4 != position4 || enc5 !=position5 || enc6 != position6 || enc7 !=position7 || enc8 != position8 || enc9 !=position9 || enc10 != position10 || enc11 !=position11) {
    Serial.print("Encoder1 = ");
    Serial.print(", Encoder2 = ");
    Serial.print(", Encoder3 = ");
    Serial.print(", Encoder4 = ");
    Serial.print(", Encoder5 = ");
    Serial.print(", Encoder6 = ");
    Serial.print(", Encoder7 = ");
    Serial.print(", Encoder8 = ");
    Serial.print(", Encoder9 = ");
    Serial.print(", Encoder10 = ");
    Serial.print(", Encoder11 = ");
    position1 = enc1;
    position2 = enc2;
    position3 = enc3;
    position4 = enc4;
    position5 = enc5;
    position6 = enc6;
    position7 = enc7;
    position8 = enc8;
    position9 = enc9;
    position10 = enc10;
    position11 = enc11;
    // if a character is sent from the serial monitor,
    // reset both back to zero.
    if (Serial.available()) {;
    Serial.println("Reset both knobs to zero");

    I have also uploaded the examples/teensy/usb_joystick sketch and can then see teensy as a usb game controller however the button do very wierd and wonderful things when encoder turned and obviously dont count correctly.

    Any help would be greatly appreciated
    Last edited by Shumey; 07-06-2021 at 09:33 AM. Reason: Additional information added

  2. #2
    I think most encoders are pretty rubbish. The cheap ones at least. You could try fixing it in software e.g. something like if (abs(position1 - enc1) > 4){ignore();} but I think the root cause will still be there.

    In terms of analogue input, the function is analogRead(pin). Connect the wiper of a potentiometer to the pin and the other terminals to GND and +3.3V. Simple.

    I don't know about Windows game device, but if you change the USB type to keyboard + mouse + joystick, does that work?

    And in terms of your code, if you want to develop your programming, learn about arrays and for loops. e.g.:

    const int numberOfEncoders = 11;
    Encoder allTheEncoders[numberOfEncoders] = {
        {0, 1},
        {2, 3},
        {4, 5},
        {6, 7},
        {8, 9},
        {10, 11}.
        {12, 14}.
        {15, 16}.
        {17, 18}.
        {19, 20}.
        {21, 22}.
    long encoderValues[numberOfEncoders];
    for(int i=0; i<numberOfEncoders ; i++){
        encoderValues[i] = allTheEncoders[i].read();
    That's not complete code and I've not checked it compiles, but it should hopefully give you an idea get going with.

    Hope that helps.

  3. #3
    if you are getting "jumps" meaning 1 click on your encoder produces several counts, it's most likely a bouncing issues. Meaning inside encoder the mechanical contacts literally bounce and cause extra fires. This happens super fast, but these MCU's are fast enough to detect the bouncing.

    a few ways you can address this
    1) There are libraries that can be use to handle bouncing.
    2) maybe put a cap across the signal pin and ground (experiment but 10uF to 100uF may do the trick, This will reduce/eliminate irregular voltages within a short time period
    3) do you own software debouncing, generally when you get a pulse, compare that time (millis()) with the previous pulse. If it's greater that some limit, consider it a legitimate pulse.

    Something like...

    if (pulse && (millis() - oldTime) > 20){ // consider anything pulses over 20 ms apart a legitimate pulse
    // its legit
    oldTime = millis();

    // your pulse processing code


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