Please see all COVID-19 updates here as some shipments may be delayed due to CDC safety and staffing guidelines. If you have an order or shipping question please refer to our Customer Support page. For technical questions please check out our Forums. Thank you for your continued support.

Member #635630

Member Since: January 6, 2015

Country: United States

  • This project proved to be EXACTLY what I needed to make a sine-wave generator for testing the brainwave monitor I'm designing. Here is how I modified it. The line:

    while ((millis() - Mils) < 1) {};

    keeps the frequency correct second by second. And the

    byte multiplier;

    determines the number of cycles per second. "multiplier" can be changed as the program runs, by plugging a grounded jumper into the different Arduino inputs that you have pre-set in this sketch.

    float in, out;
    const int LED = 11;
    unsigned long Mils = millis();
    byte multiplier = 1;
    void setup()
    pinMode(2, INPUT_PULLUP);
    pinMode(3, INPUT_PULLUP);
    pinMode(4, INPUT_PULLUP);
    pinMode(5, INPUT_PULLUP);
    void loop()
      if (digitalRead(2) == LOW)
        multiplier = 1;
      else if (digitalRead(3) == LOW)
        multiplier = 10;
      else if (digitalRead(4) == LOW)
        multiplier = 20;
      else if (digitalRead(5) == LOW)
        multiplier = 40;
      for (in = 0; in < 6.283; in += (multiplier * 0.006283))
        while ((millis() - Mils) < 1) {};
        Mils += 1;
        out = sin(in) * 127.5 + 127.5; // 127.5

    I use it with the first circuit shown at: http://www.wa4dsy.net/robot/active-filter-calc Entering 50 as the number for both input parameters of their calculator, gives the perfect values needed to filter this waveform

No public wish lists :(