An air raid siren powered by a brushless motor (RCTimer 5010-360KV). It has a total weight of 440 gr. So it can be mounted on a copter.

The only Part that needs support is "Sirene Rotor1".

I print on a replicator 2. The files "Sirene Wand" and "Sirene Deckel" are oversize. If you print it on a replicator 2 you have to cheat a little bit by moving the parts towards you (in y-axis).

Here is how it sounds...
https://www.youtube.com/watch?v=xOa8Jh2RAUA&feature=youtu.be

The aditional parts you need:

• Motor: RC Timer 5010-360KV
• RC-Stuff: an ESC with 20A, something to get the signal to the ESC
• 4 screws (M3 20mm)
• a bearing (5mm inside, 11mm outside, 4mm width - the same as the one used in the RCTimer motor)

I already thougt about using an arduino or rasperry pi to do some kind of alarms. Shouldn't be that hard to realise. But i haven't work with this stuff until now... But would be a very effective alarm clock in the morning :D