Half paraboloid (parabola of revolution) ear trumpet

thingiverse

An owl moved into my neighbourhood. I could hear it every morning, but I never could see it. I built this half paraboloid, which I had hoped I could use to find the direction of the "too-hoo" sound in the morning and see the owl. The parabola has a focus 30 mm "above" the base, so if you hold the bottom of the bowl at about the rear edge of your ear, it should focus the sound right near the opening of your ear canal. Because it is so small, this parabola will only focus fairly high frequency sounds - honestly it only gets good at about the limit of human hearing. However, it does reject sounds from the sides very well. The owl has decamped for a place with more rodents, I suppose, because the too-hooing stopped between the time I had printed the trumpet and the next Saturday. An ambitious designer could remix this to have a pair of these with ear pads and a half-hoop to be worn like headphones. Then you would really look like a doofus so make sure to use a bright colour. Print Settings Printer Brand: RepRap Printer: Prusa i3 ZRIB Rafts: No Supports: No Resolution: 0.3 mm Infill: 20% Notes: If you only have a 200mm by 200mm print surface, use the version that has been rotated 45° so that it will fit in your printer. How I Designed This I used FreeCAD and wrote some python. Create a Part Design. Create a Sketch in the XY plane. Enable the Python console (View|Panels|Python console) Paste the Python code from Paraboloid.py into the console. Wait a long time for FreeCAD to draw the shape. Close the sketch. Rotate the sketch about the drawing's vertical axis 180°. Export as STL.