About this 3D model
I used an existing Thingiverse On Air sign from crimsonlion518 and a 9v battery holder from ahmetcemturan to build this On Air LED Flashing sign for Filament Friday. The design was completed in Tinkercad and the electronics were built on a CNC milled circuit board. The electronic circuit is an Astable Multivibrator circuit that creates the back and forth LED flashing without any microcontroller. More info in my YouTube Video: