Arduino enthusiast Alberto Bietti has created a simple and noisy project based on an Arduino board - his ultrasonic theremin. This is a type of musical instrument that can be played without any physical contact, thus the ultrasonic sensor which measures the distance between itself and an object. Using the Arduino sketch the distances returned can be made proportional to sound values and thus the musical "instrument" is born... for example:
The use of the bare speaker with the Arduino leaves the audio quality a little poorer than expected, however the project is fun and would be a good form of entertainment or inspiration for younger builders. Click here to get started on your own version. And for more, 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.