Update 28-05: Convert the big Horn into a Siren Whistle (loud!) - fast and easy print!
Many thanks to all for the positive reactions and appreciati...on for this design! This model is currently participating in the contest on Printables. www.printables.com/model/457446
Update 10-05: I have added a membrane cap with grip. Made by @Rotten_33336 at Printables. This is for easier installation if you do not manage to position the membrane cap right with the original one.
This little powerhouse knows how to produce a sound that will scare you.
Very easy printing. All parts can be printed without support.
I printed them with 0.4 nozzle and 0.2 layer thickness and 15% infill.
For the small horn I used a brim of 2mm, but it can be printed without brim.
Print all as positioned in the STL's.
Simple assembly without glue or rubber bands. https://youtu.be/93vNi6S7Eok
Before assembling, check the Membrane Cap and the left recess in the Housing where it is placed if there are no rough parts after printing. If so, sand them smooth.
The membrane for creating the sound can be made from a (thin) plastic bag. I used a PE food bag, but feel free to experiment with other types of bags. Do not use thicker plastic.
There is play between the 2 parts. If this turns out not to be enough for your print, print the membrane cap slightly smaller. After installation, the membrane cap must clamp properly!
If you want to replace the membrane, you can easily remove the membrane cap with a pen or something similar. Simply push it out again via the connection of the air horn.
A small airhorn and a larger one (more luxurious and thicker) have been added.
The air horns can be scaled in length (Z) producing lower and heavier tones.
Example how to assemble and the sound (not unimportant): if you haven't watched (listened to) them yet, see the video above.
Place a plastic bag (only one layer) over the Membrane Cap and push it in. The Membrane Cap should not be pressed too tightly. Play with the distance a bit. If you have pressed too far, pull them back with the bag.
When the cap is too tight it is a screeching sound. Try pulling the cap back a tiny bit! (you can see me doing it in the video also) There are basicly 2 sounds: one with the cap very tight (very screechy) and a tiny bit more space where the whole membrame vibrates. Sometimes blowing harder will enter the second stage.
After installation you can cut off the rest of the bag. The Membrane Cap sits just below the surface of the housing so you have a guide edge to cut along.