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Author Topic: Peizo Sensor to detect hits from a bat  (Read 1347 times)
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Hello,

I'm working on a project to sense when an object is hit by a bat/stick and then register that hit on a website.

At this point I'm considering to use a Peizo sensor connected to an Android phone to send the count to the site counter.

I'm wondering if anyone has any suggestions as to the sensor selection and any off-the-shelf Android apps for something like this?

Thanks for your help!
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Hi,

I've been using Peizo pick up to detect a drum hit quite successfully. I run the peizo through a small amplifier chip and then read the anaolg signal on the Arduino. I find that looking for a a value above 700 will detect any sort of hit to the drum skin.

I use an LM386 amplifier chip connected directly to the peizo (they're tiny) and then I can run the sensor wire as long as I want.

Let me know if you want further info on this and I can send you some schematics.

Dok.
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Those things generate fairly high voltages, enough to trigger a mcu's input.

I would put a 1k resistor in serial with a diode to an input pin. Also hang a rc network on the input pin to ground. The peizo will generate multiple pulses (likely thousands) each hit and you  don't want to detect them as thousands of hit. The diode + capacitor allows a built-up and a discharge. You will likely play with the rc values to get your desired detection effect.
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I'm also considering a project that would involve detecting drum hits,
Quote
I would put a 1k resistor in serial with a diode to an input pin. Also hang a rc network on the input pin to ground. The peizo will generate multiple pulses (likely thousands) each hit and you  don't want to detect them as thousands of hit
I was thinking about that same thing today, and I was gonna try to 'debounce' it somehow in the software but I do like the idea of a hardware fix, would make my coding easier.

dhenry, i'd be interested to know if you've done this before.

dedokta, if you still have some schematics available then I'd love to look at them

jbiondi, did you get your project working in the year-and-a-bit since you started this thread?

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Dubuque, Iowa, USA
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Good link for filtering piezo signals:

http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/f2012/asj42_gs368_ln226_awh49/asj42_gs368_ln226_awh49/index.html
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I'm also considering a project that would involve detecting drum hits,
Quote
I would put a 1k resistor in serial with a diode to an input pin. Also hang a rc network on the input pin to ground. The peizo will generate multiple pulses (likely thousands) each hit and you  don't want to detect them as thousands of hit
I was thinking about that same thing today, and I was gonna try to 'debounce' it somehow in the software but I do like the idea of a hardware fix, would make my coding easier.

dhenry, i'd be interested to know if you've done this before.

dedokta, if you still have some schematics available then I'd love to look at them

jbiondi, did you get your project working in the year-and-a-bit since you started this thread?



I have a project that measures the spacing of clock/watch ticks to help set an even beat and to time the mechanism.  Since ticks are not the cleanest signal in the world, I amplified and filtered them with op-amps to help prevent false initial triggers from ambient noise.  I then fed the filtered output to a lm393 comparator which then was used to trigger a 74HC221 timer.  The microcontroller (PIC) uses the output of the 221 timer to mark the leading edge of a tick.  All other extra pulses and noises between ticks are effectively locked out by the 221 for most of the period between ticks.  I adjust the length of the pulse so that the circuit only listens in a narrow window of time for the next tick.  The 221 is non-retriggerable meaning that once triggered, it ignores the trigger input until the timer expires.  This may be overkill for your project, but it may be useful to somebody at some point.  It sure solved my problem of getting consistent single trigger to the micro.
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Experience, it's what you get when you were expecting something else.

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At first, I thought you were talking about a mouse with wings....

What are you planning to hit with your bat ?    You will need to think about the
durability of your device.   Your sensing device may become either broken or
detached.
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