Buzzer Choice

[GjBob]

Since this is my first post i would like to say hello to you all. On second hand i wanted to ask a question here, maybe someone has already stumbled in this kind of thing. I need to introduce a buzzer in my project to alert people in case of a falling uav in situation like technical failures. I need to to be one as loud as possible and i need have a wide range of frequency since i will need to play 2 or 3 different sound

[Mr Smiley]

Fire Alarm Klaxon 

Is it to be located in a very large/small area,  indoors /outdoors, Small room/corridor.

 

[aargee]

Mounted on the UAV (simple reversing beeper would do?) or an earth based device to notify a wide area on the ground to look up? (Air raid siren)

[GjBob]

It will be mounted directly on the uav so it can't weight to much and i rather would prefer something controlled from a pwm to produce different tones ( if i understood well from some datasheet if the buzzer doesn't have an internal circuit it will produce the loudest sound when driven by a signal at the resonant frequency but will produce also sound at other frequencies). It need to be powerd by 5v.

[tszaboo]

Are you sure, that the electronics solution is the safest/easiest? I would guess, that a CO2 cartridge with an electronic/mechanic firing and some kind of horn would weight less, and be more alarming than any electronics horn. They go for quite some time, 20-30 secs easy for a 9g cartridge.