New Guy Here - Wanting to build Siren

Thread Starter


Joined Jul 31, 2008
Hey everyone, I just stumbled upon this site and I had to sign up right away. I have a little self-taught knowledge of electronics and circuits. Most of my interest came from doing car wiring. Anyways, really quickly... I am wanting to put together an alarm siren (for fun really) and I was wondering to play around with different tones and pitches... Maybe someone has a link more specific to this or something? I took apart one of the sirens that changes tones from like a police siren to everything else and I would like to put together something like that. Anyways, time for bed. Sorry for being so quick. Later


Joined Mar 24, 2008
One of the first projects I built multiples of was a simple 2 transistor siren circuit, when I get a chance I'll post the schematic. Odd really, it was on the other side of another schematic I looked up for another post.


Joined Mar 18, 2007
IC LM3909(or equivalent NTE 876) produces evenly spaced beeps which create fun or hypnotic effect.BUT, IC LM3909 not easily found in the market.


Joined Jul 17, 2007
Hmm - the LM3909 was developed to flash LEDs for a very long time from a single 1.5v battery. I've never seen an application for sound using that IC. I suppose it could be used, but starting with an obsolete (and expensive) IC seems to be a rather frustrating way to go.


Joined Mar 24, 2008
I think I still have a pill bottle kicking around full of them somewhere, though I may have given them away to an astronomy club (to make blinkers for a dark path leading to a big telescope).

The 555 has some interesting VCO configurations. Wonder if that could be turned into a siren?