2 thoughts on “Buzzer Does Input And Output

  1. I’d built a project for my brothers track car about 4 years ago that detects engine knocking. It displayed the scale of the knock sensor on a number of LEDs (about 12 green, yellow & red all up) as well as tones via a headphone jack. This was used for fine tuning the engine in his workshop & as a dash display during test drives.

    At the time of building this my brother and I lived 6 hours drive apart, building it with the car present wasn’t an option. So I opted to use a piezo buzzer like that in the article to get the project off the ground.

    Car knock sensors are essentially a piezoelectric disk or ring built to create voltage at a very specific vibrating frequency. This frequency is that which knocking/pinging/detonating makes through the engine block.

    Knowing the curve and the voltage at the resonance point of the knock sensor meant I could build a reliable scale for the LED to Human eyeball connectivity.

    Sadly I have no video of the final device, but I do have a very early video I made for my brother just when I was getting things started. The final device also did not stay in that old boost gauge, though I have that lying around somewhere.

    I must say though, I love the idea of using them as a button with feedback. I might have to implement the idea in something myself one day. Or maybe I could log when my cat is feeding, her stainless steel bowl would be purrfect for capturing vibrations at snack time.

    [youtube https://www.youtube.com/watch?v=Jo_OMDANjeU&w=560&h=315%5D

  2. I’m still not sure I’d fully trust the voltage to stay where I want it at those voltages and frequencies.
    Pizeo electric materials and drivers can give you a bit of a zap if you’re not careful.
    Stacking them on top of each other, with little stand offs or adding little levers to them, can be a good way to increase the range of movement and/or output force/output voltage.

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