Some say the spectre of global nuclear annihilation is closer than ever before. What better time to head to the workshop to prepare for the coming apocalypse? [MrExpert] is here with the build you need – an air raid siren you can print at home.
It’s a simple build, which makes it fun and accessible for just about anyone with a 3D printer. Rotational power is provided by a brushless outrunner motor hooked up to an ESC, controlled with a servo tester. The rotor and frame for the parts are 3D printed, and held together with a handful of standard fasteners.
Initial testing proves that yes, it does work and generates a rather earsplitting tone. The second revision improves upon this somewhat. However, the key to getting that authentic sound is in the sweep of the tone. By replacing the servo tester with an Arduino or other micro that can generate smoothly sweeping pulses to ramp the rotational speed up and down, you’ll get much closer to that genuine the-sky-is-falling timbre.
It’s certainly not rocket science, and would make a great project to whip up with the kids on a rainy weekend. While you’re at it you can share the wisdom behind the duck and cover technique, but maybe save the geopolitical rants for when they’re a bit older. We’ve seen air raid siren builds before, too – like this sturdy wooden unit.
might want to wear safety glasses when running at high RPM. Also seems like it could use some balancing. and maybe a little horn will make it a bit louder.
+1
Heh, I have the big brother of that! It is from the 1940’s and some moron scrapped the housing, but I have the air chopper and 5HP 220V motor. Once in a while I fire it up (on 110V) and it is a riot. It takes a bit to spin up and it is a very cool effect. I have been meaning to hook it into a big (like 4″ diameter) industrial push button with a one shot for use as a door bell. Our dogs are totally unreliable and occasionally people park on the far side of the yard and we can not see their car or hear them knocking at the door. That siren, which can he heard into the next county, should solve the problem. I will have to look into the little one!
we a got 12v siren at a junk stand at the car show, want to wire it into the mini sometime. Probably like yours only smaller. The unit on the back of it to make it change direction is broken though, so need to make a circuit to replace that
Seen one on youtube a while back made from Plywood and it was quiet large and very noise
https://www.youtube.com/watch?v=XAfvOjdZpkg
https://www.youtube.com/watch?v=2Tr6hCZAVhI
I have one, probably similar to yours, that I hooked up to a custom built alarm system for my shop. Needless to say, if that place gets broken into, everyone in the neighborhood is going to know about it!
I swear to god you are bugging my computers, I watch something and show an interest then poof it’s on hackaday a few days later….. there is a much better sounding not so much better looking one I’ve ordered prints of…. https://youtu.be/FSjRAUovvA8
pic doesnt match video (shows earlier version) and both are designed wrong… much better sirens out there. but cool idea!
Neat, but I wonder how much of that noise is just the motor spinning up on its own? The printed siren that was linked in one of the other comments sounds great, but this one I’m not so sure about.