My project entails using piezo's to trigger a midi track on my laptop(using Ableton Live). As new to this I could do with some advice on which product to purchase from yourselves. I'm using windows 7 and I'd like to use at least 24 piezo's in my project.
Thanks a lot
The Arduino will traditionally use an analog input to sense the knock. To get 24 analog inputs you would probably use a multiplexer shield like the one from Mayhew Labs: http://mayhewlabs.com/products/arduino-mux-shield
Unfortunately I think the traditional knock sensor circuit (1 MOhm pull-down) relies on the sample/hold capacitor inside the A/D converter. You might need to add a capacitor to each input so you can sense knocks that happened while the A/D was connected to other channels. The internal Sample/Hold capacitor is 14 pF so a capacitor about 150 pF across the 1 MOhm resistor might store a suitable charge.
Big thanks for replying. As I'm a total novice to this and I'm contently learning, I'm trying to get my head around it. I've used piezo's connected to a drum module/drum brain and then connected the midi to my laptop and then to Ableton and that triggered the samples without any other external power (I guess this is what you mean). The only problem was that it only has 8 analogue inputs so that's why I started looking at the Arduino thinking they would do what my drum module/brain did. :~