For those interested in sensing the enviroinment around a particular area, or looking to make a device that reacts to sounds in order to trigger a camera, burglar alarm or a type of game - a sound trigger would be a welcome addition to the project. And doing so is quite easy, as explained by Arduino forum member Peter Lin. He has used a simple piezo speaker as they can generate a slight current from sound level pressure, and this is measured using an Arduino analogue input. From that stage Peter described how to (for example) switch a transistor based on the sound levels.
You can recreate this type of project in less than an hour, so check out Peter's notes in the Arduino forum to get started. And we're on twitter and Google+, so follow us for news and product updates as well.
It can be used as a noise-maker driven by your microcontroller for audible feedback of events, and it can also be used as a knock-detector input to sense events and react to them. Includes a built-in 1M resistor to allow the piezo element to detect shocks. For more information and to order, please visit the product page here.