Hi all,

I would appricate some help on how to build with a Timer chip if applicable a slow rising buzz, then rising up into the inaudio bandwidth, say 13khz, the starting FREQ, Im not sure of, but its the slow build up of the sound Im after taking around 17seconds to complete.. then starts again say after 7seconds.. any any hints tips clues/ links.. would be most helpful..
Sorry I forgot to mention would like a push button switch to start the sound off..

thanks very much if ANYone can solve this mind boggling thing Im after..

from
redlight000

 

You might find a siren circuit works - http://www.discovercircuits.com/S/siren.htm

 

Hi Beenthere,

thanks for the reply, can you suggest which siren to go for? as there's so many there..

cheers
from
Redlight000

 

I think what you're after is a VCO (Voltage Controlled Oscillator) with a ramp input. The ramp produces a slow sawtooth, that when feed into the VCO would produce something like what you want.

 

I think what you're after is a VCO (Voltage Controlled Oscillator) with a ramp input. The ramp produces a slow sawtooth, that when feed into the VCO would produce something like what you want.

Hi Bill,
I dont know where to look for a VCO? and ramp input!!! have you a basic Link? that might help?

many thanks
redlight000

 

I don't have time to design it, but I can point you in the general direction. It may not be satisfactory, you'll just have to protoboard it and see.

 

Hi Bill,

many thanks for the starting Point.. at least I've got some idea now!!!