# How do I make a police siren? **URL:** \ **Category:** Factual Questions\ **Created:** [May 21, 2003, 2:45pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564 "2003-05-21T14:45:00Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![the\_idler](https://avatars.discourse-cdn.com/v4/letter/t/e8c25b/32.png) [@the\_idler](https://boards.straightdope.com/u/the_idler)\ **Post date:** [May 21, 2003, 2:45pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/1 "2003-05-21T14:45:00Z")
First off I’ll stress this is for a local amateur dramatics play and NOT for imitating a policeman. My wife is a member and has volunteered my good self to help out with props and stuff, and I’m pretty clueless on electronics. I’m not talking about the actual siren either, just the revolving flashing blue bulb will do the job. Any tips greatly appreciated Oh, and to all those who replied to any of my earlier questions thanks a lot, I had some technical problems after posting and couldn’t reply for a few days by which time the threads had dropped off the board. ---
**Author:** ![Peter\_Griffin](https://avatars.discourse-cdn.com/v4/letter/p/e480ec/32.png) [@Peter\_Griffin](https://boards.straightdope.com/u/Peter_Griffin)\ **Post date:** [May 21, 2003, 2:47pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/2 "2003-05-21T14:47:08Z")
IIRC you can buy one of those revolving lights at any Radio Shack. Or you could probably pick one up at a party store. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [May 21, 2003, 3:14pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/3 "2003-05-21T15:14:29Z")
[Go here.](http://www.hmtrad.com/instr/winds/flutes/windmisc.html#novelties) Good metal ones for $25, plastic cheapies for less. ---
**Author:** ![the\_idler](https://avatars.discourse-cdn.com/v4/letter/t/e8c25b/32.png) [@the\_idler](https://boards.straightdope.com/u/the_idler)\ **Post date:** [May 21, 2003, 3:23pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/4 "2003-05-21T15:23:11Z")
Thanks Peter, I’ve looked at their website but can’t find one on it. Bosda, it’s the flashing bulb unit I’m really after not the noise effect ---
**Author:** ![Peter\_Griffin](https://avatars.discourse-cdn.com/v4/letter/p/e480ec/32.png) [@Peter\_Griffin](https://boards.straightdope.com/u/Peter_Griffin)\ **Post date:** [May 21, 2003, 3:35pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/5 "2003-05-21T15:35:38Z")
Here you go buddy… [http://cheapnovelty.com/beacons\_\_\_traffic\_lights.html](http://cheapnovelty.com/beacons___traffic_lights.html) [http://www.davesdeals4u.com/electronics.htm](http://www.davesdeals4u.com/electronics.htm) I did a google search for “rotating beacon” and “flashing rotating light”. Hope this gets you started. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [May 21, 2003, 3:51pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/6 "2003-05-21T15:51:25Z")
Siren is what makes the noise. The light is not called a siren. ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [May 21, 2003, 6:29pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/7 "2003-05-21T18:29:18Z")
An old-fashioned hand-cranked siren works on the principle of rapidly spinning holes of alternate sizes. I believe a hand-cranked siren can be made with two cans, one slightly larger than the other. Cut rectangular holes in the side of the larger can. Then, cut flaps in the smaller can and bend the flaps inward. Next, make a hole in the bottom of both cans so a crank can be attached and place the smaller can inside the larger one, bottom-to-bottom. Attach a crank and you’re ready to go! ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [May 21, 2003, 6:39pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/8 "2003-05-21T18:39:54Z")
Or you can [try this](http://www.techlib.com/electronics/noisemakers.html) if you want to make an electronic siren. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [May 21, 2003, 6:40pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/9 "2003-05-21T18:40:55Z")
Jeff Olsen, you need to spin the siren _way_ faster than you can ever spin iot by hand. The hand-cranked sirens have a multiplying gear. ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [May 21, 2003, 7:01pm UTC](https://boards.straightdope.com/t/how-do-i-make-a-police-siren/176564/10 "2003-05-21T19:01:10Z")
In that case, go with the electronic one. 🙂