Half paraboloid (parabola of revolution) ear trumpet

thingiverse

An owl moved into my neighborhood one day. I could hear its familiar hooting every morning, but no matter how hard I looked, I never managed to catch a glimpse of it. I decided to build a half-paraboloid that would allow me to pinpoint the source of the "too-hoo" sound and spot the owl in action. The parabola's focus point is located 30 millimeters above its base, so if you hold the bottom of the bowl at about the edge of your ear, it should focus the sound right near the opening of your ear canal. Due to its small size, this parabola will only effectively focus high-frequency sounds - it really excels up to the limit of human hearing. However, it does an excellent job of rejecting sounds coming from the sides. The owl has since moved on to a location with more abundant rodent life, leaving behind a silent landscape between the time I printed the parabolic trumpet and the following Saturday. An ambitious designer could take this concept further by combining two of these units with ear pads and a half-hoop, creating a wearable device that resembles headphones. To avoid drawing unnecessary attention to oneself, it's best to use a bright color for this design. Print Settings: Printer Brand: RepRap Printer Model: Prusa i3 ZRIB Rafts: No Supports: No Resolution: 0.3 mm Infill Percentage: 20% Notes: If your print bed is limited to 200mm x 200mm, consider using the version that has been rotated by 45 degrees to ensure it fits within your printer's dimensions. How I Created This Design: I employed FreeCAD and Python to bring this design to life. Here's a step-by-step guide on how to recreate it: First, create a new Part Design in FreeCAD. Next, create a sketch in the XY plane. Open the Python console by navigating to View > Panels > Python Console. Copy and paste the Python code from Paraboloid.py into the console. Wait patiently as FreeCAD renders the shape - this may take some time. Close the sketch. Rotate the sketch 180 degrees about its vertical axis. Export the design as an STL file.