minor issues around encoder fit

[scruss]

Noticed a couple of things when using the specified Bourns PEC11-4215F-S24 encoder:

1. The diffuser ring is too thick for the lock nut to fasten. It's 2 mm thick, and there's exactly 2 mm of thread left on the encoder.
2. The D-shaft cutout in the top is too deep to allow the encoder shaft switch to trigger.

Otherwise, it's a fantastic project and very easy to make. Yes, I used a Seeeduino XIAO, too

Workarounds

I made the central part of the diffuser thinner so the lock nut would fasten. Excuse the OpenSCAD, it's all I know:

bbox = [ 49.988811, 49.994404, 2.000000 ];
minima = [ -25.000000, -24.997202, 2.700000 ];

difference() {
    translate([-bbox.x/2, -bbox.y/2, 0])translate(-minima)import("qtpyknob-diffuser.stl");
    translate([0,0,0.8])cylinder(d=bbox.x/2, h=bbox.z);
}

For the D-shaft cutout, a blob of Blu Tack of just the right size mostly fixes the issue.

[todbot]

Doh! So many encoder options to pick from.
I see now that the ones I'm using are PEC11-4120F-S0018 equivalent (i.e. 20mm shaft with 7mm threaded barrel and you've got a 15mm shaft with a 5mm threaded barrel. I think your option is more common. I have a bunch of extra encoders from some modular synth projects. :)

I'll add a note about expected encoder in the README and keep this issue open for others to easily see it. Thanks! I totally forgot to specify the encoder parameters.

[bdgraham]

Obviously due to the negligence of the user (me) not reading the readme fully, the rotary encoder I have won't fit into the d-shaft cutout as the shaft I have is the regular kind. Do you have a qtyknob-knob.stl available with the regular size shaft cut out? All measurements are spot on otherwise. If not, totally fine as I can extract that portion in blender if needed. Awesome work, I've really wanted to make a functional volume knob for a while! I also created an svg for the diffuser as I am going to be using a laser cutter for that part. If you would like me add that file to your repo, please let me know!

For reference, this is the rotary encoder I am using - https://www.amazon.com/dp/B08728K3YB?psc=1&ref=ppx_yo2ov_dt_b_product_details

[todbot]

Hi @bdgraham
I can provide solid models from the included Fusion360 file if that'd work better in Blender for you. But no, I've not made either a knurled-shaft or a slotted-shaft version of the knob cap.

And yeah if you have a diffuser SVG you'd like to share, submit a PR, I'd love to add it!

[bdgraham]

@todbot A solid model would be great, thanks! Will need write perms to repo to submit svg file. Let me know if you want the readme updated as well, otherwise I was just going to leave it alone. The diffuser svg has the same dimensions as the existing diffuser stl.