Bitonal Cat Whistle

It's a whistle shaped like a cat face! This was designed in the vein of an emergency whistle and can reach 120dB up close, which means it is not a toy and should not be given to small children.

If you are going to test it, please first consider whether there are pets or other people around it will bother, and test it outdoors if you can. If you are going to test it a lot or use it a lot, you may want ear protection.

I tested these to be 110dB up close with a moderate blow and 123dB up close with a hard blow. It's about 105 dB from about six feet away, with a hard blow, and so on. (I’m just using a phone app to test it and these things will vary by person and environment, so take this less as a guarantee and more of a ‘what to expect’.)

The frequencies may differ a bit between prints due to small size differences (as well as temperature and other air conditions), but I tested the left chamber to be about 3050 Hz and the right to be about 3450 Hz.

The collar is meant to serve as a limited tooth notch for keeping hold of the whistle.

Tips for printing:

• 3 perimeters/walls

• Aligned seams, with painted seams to avoid the whistle innards and various sharp corners, many of which serve a functional role in the whistle. I recommend these locations on the outside of the whistle:

• Set bridging angle to 180º. (In PrusaSlicer this is Print Settings > Infill > Advanced > Bridging angle.)

• For the bridging layer that closes the whistle chambers, use a height range modifier and change 'infill/perimeter overlap' to 100%. (In PrusaSlicer you right click the object in the list, select ‘Height Range Modifier’, set the modifier (3.8mm to 4+mm), then right click that Range on the object list and Advanced > Infill/perimeters overlap to 100%.)

• The chamber ceiling bridging layer should begin at 3.8mm.

• The distance between the chamber floor and the bottom of the bridging layer should be 3mm.

• Classic slicing

• I also recommend making sure ‘avoid crossing perimeters’ is turned off

The walls are largely 0.12mm wide so this should work with a 0.6mm nozzle, but the sound may be a bit different.

I am including a couple variations on the main design:

• one where the eyes are 0.2mm taller than the mouth so they can be different colors per layer

• one with a blank face so you can do any cat face you want

• one with a blank face but 0.4mm thicker so you can subtract 0.2mm-0.4mm details