A doorbell is pretty necessary for an operating hackerspace to implement the idea of openness, thus allowing outsiders to visit the place when members are inside.
An FT66T integrated circuit generates the sound of Für Elise and is directly connected to a small speaker. A 6800 µF capacitor is connected in parallel with the power supply, so after the button is released, the sound continues playing for a small amount of time.
Hungarian: Az alábbi csengőt csak akkor használd, ha tudod, hol csenget es biztosan oda akarsz jönni (értsd: nem lakásszinhaz) thx hspbp
English: Only use the doorbell below, if you know where the bell rings, and you really want to get in there (i.e. not amateur theatre) thx hspbp