NOTE: After some testing, it turns out this design as printed in black PLA isn't perfectly light-proof. Other more opaque filaments (eg white) may be better - testing is ongoing.

This is a simple capsule for making DIY "vactrols" - an LED paired with an light dependent resistor (LDR). The default values in this design are for a 5mm LED and a similarly sized GL5516 CdS cell LDR.

This design was inspired by the vactrol capules you'll often seen in photos of Nonlinear Circuits (NLC) eurorack moduled build documentation.

Creality

Ender-3 v2

No

No

0.2

100%

Printed with a 0.4mm nozzle and 0.2mm layer height. Cura default slicing tolerance (Middle).

I like to sand off the end of the LED so it's flat and superglue it to the LDR, but this probably isn't necessary.

The LED goes in the small cylinder with it's wires poking through the tiny holes in the base, the LDR goes in the larger cylinder in the same fashion. The two cylinders snugly fit together and hold by friction (if your printing tolerances are correct ... you can tweak the fit_tolerance value in OpenSCAD / Customizer to get it right, or if its close but a little loose, add a dab of glue). The fit should be snug so no light gets in.

You may find the tiny holes for the wire print closed over (due to elephant footing in the first layer, specific print settings) - just punch them out with a needle if this is the case. The holes are designed with bevels on the base to try and avoid this issue. Only make the holes as big as they need to be to avoid light leakage into the capsule.