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Ultrasonic PWM with Arduino 1.0

generate silent 20kHz PWM

  1. RacingMat
    Some Hbridge can accept up to 20KHz PWM:
    because these ultrasonic frequencies are inaudible, you don't hear anymore the humming sound of your motor at low speed.

    This code allow the Arduino UNO/Nano to increase its standard poor 490Hz PWM up to 20kHz superman.gif

    The code has to be adapted if you're using MEGA board for instance.
    pin pwn.jpg

    Check the datasheet of your Hbridge if it can accept ultrasonic PWM.
    - For example VNH2SP30 chip can do this (but is limited to 16V) like Motomonster.
    - Unfortunatly, 36V VNH3SP30 chip cannot reach 20kHz PWM

    Hear the difference:

    Some more information brought by Pipis2015
    thanks for this feedback !

    If you want to use Pololu_Dual_VNH5019 stacked onto the Arduino:
    you only need to change

    ultrasonic code:
    int inApin[2] = {
    7, 4}; // INA: Clockwise input
    int inBpin[2] = {
    8, 5}; // INB: Counter-clockwise input
    into this:
    int inApin[2] = {
    2, 7}; // INA: Clockwise input
    int inBpin[2] = {
    4, 8}; // INB: Counter-clockwise input