The ultimate geek's Birthday Cake

Dear Arduino community,

I would like to show you my open source product based on Arduino - BitCake. That's electronic cake with candles you can blow out.

I use ATTiny44 MCU programmed as Arduino. There's piezo sensor and air trap to detect blowing using resonance effect. Arduino sketch constantly takes signal samples and makes partial Fourier transform to read amplitude around 750 Hz frequency. The device has astounding sensitivity and doesn't react on loud sound!

When blowing is detected, LEDs are blinked with randomly generated period, phase and time-to-live. The phase hops ±180 degrees depending on the blowing amplitude so candles behave very lively.

Official webpage of the project is