Custom HOTAS project: Digital Hats

As said in my earlier post I disassembled my ancient Logitech Extreme 3D Pro and the digital hat design was beautifully simple, an array of 4 tactile switches pointed towards a central shaft with a rubberized concave piece on top and a mounting solution in the bottom that let it shift a small amount without rotating or falling out or in using a square peg in a slightly larger square hole with a lip on one side and a screw on the other.

I’ve replicated the design in 3d printed pieces and M3 and M4 vitamins, sadly photographing black plastic is very thankless, to see any details you need to bump it up to the point where it looks really bad, looks better in-person, all visible surfaces will be solvent smooted as well, and the top concave piece will not be ABS in the final version, will be filaflex (rubber filament) for a nicer feel.

The ugly gap between the 2 pieces of the top hat part have been corrected for in the model, I didn’t leave enough space for the M4 bolt head, and the top part will be printed in flex, just attached a temporary ABS version with some hotglue to test. The nut will be hidden in the final version inside a plastic collar piece and the hat itself will be inside a indented part on the otherwise flat surface.
Sorry about the levels but I wanted to make the 4 tactile switches visible.
The model in Modo, the main enclosure with the 4 screw posts is split into 2 to let me insert the peg and nut inside. White part on top is a separate part that will be printed in flex.
Enclosure hidden to show the internal mechanism, complete with 4 tactile switches and the bottom square plug is slightly oblong shaped (like an american football) to make it fit into a slightly larger square hole in such a way that it lets it rock in a pivoting motion, but not slide around as much. The curved “wings” facilitate the same thing, lets it rock but doesn’t let it push through the bottom. There is a nylon locking nut either side the plug to lock the M4 bolt going down the center’s rotation and to stop it falling out.
View of the gap of the plug, about 0.2mm sideways and vertically so the nut when tightened against the peg doesn’t stop the rocking motion.

I find designing and printing mechanism like these very therapeutic, always fun when it works of the bat but still fun to iterate on the design to come up with fixes for problems, like I forgot to give the square peg vertical slop in my first try which made the nut when tightened down stop all motion, and if I loosened it enough for the switches to trigger the top hat piece rotated freely, which feels very weird. 10min fix luckily.

The result is very nice, the travel distance of the hat is very small, I’d say about 1mm in all directions which is about half of what the logitech one has, the activation feel is very “crisp” as well, logitech one is a fair bit mushier I assume because it uses a plastic piece to push the tactile buttons while I use a M4 bolt.

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