Air Raid Siren

UPD2: Added a version of the siren with 5 blades.

UPD1: Added a version of the siren with facets that serves as a horn. Perhaps this version will be even louder.

Video:
https://youtu.be/wPYlO7F923U

A compact air raid siren that anyone can make. Simulates the operation of a real siren. In addition to filament, you will need:
- 2205 engine for FPV quadcopter (2 pcs);
- ESC 25A (2 pcs);
- PDB (1 pc);
- SY60 or XT60 connector (1 pc)
- Arduino Nano (1 pc);
- 10 kΩ resistor (1 pc);
- tact button (1 pc);
- some hardware, wires, heat shrinkage, hot melt glue.

I recommend building a version of the siren with 8 and 10 blades, the version with 6 and 10 sounds a little low frequency. It would be possible to increase the speed of rotation of the rotors, but it is already getting scary. :) The main thing is not to use 2 identical rotors in one siren, the real sound of the siren gives the use of different rotors. Also make sure the rotors turn in the correct direction - clockwise