Now and again we see a project which is clearly outstanding, and today's example is by Khalil Klouche. Called the "Knock Knock" calculator - it's a four-function calculator that uses knocks for user input and output. You simply knock a number of times over one of the mathematical functions printed on the box, and continue "knocking out" the required expression. The calculator then replies with the answer by tapping inside the box with a solenoid. Controlled by an Arduino, it uses small contact microphones to detect the knocking. Check out the following video for a demonstration:
Kudos to Khalil for his fantasic project. For more information and other projects check out his interesting website. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
If you found the project above interesting - but not sure how to start with Arduino - then the best way to learn is with our Experimenter's Kit for Arduino: