Use a portable battery.

Connect it with the breathingmask via micro-usb.

Put the breathing-mask on your face.

Make a wifi-hotspot on your phone

Name it: Accessphone , with the same as password: Accessphone

You will be connected with a mqttt-server.

There, all frequencies are gathered and used to produce sirena-sounds,

converted by different oscillators.

Breathing-Sirenas can share all sirenas breathing in the world.

Github Breathing Sirenas