Purely printed bezels

A project log for LED Oscilloscope Mk. II

Revamping a classic

Ted YapoTed Yapo 11/21/2018 at 20:585 Comments

I spent some time playing around with 3D printed bezels again - this time, printing the diffuser as well as the bezel.  You can see the results: no bezel/diffuser (top), white bezel/white diffuser (middle), black bezel/white diffuser (bottom).  You lose some brightness with the black bezel, but the overall effect is much better because it really kills the light bleeding.

The diffuser is a single layer of 0.2mm white PLA+.  The bezel (square cells) is printed directly on top of the diffuser layer.  For white/white, it's just a single print, but to get the black bezel on a white diffuser, I had to make two separate-gcode files, and swap filament in between printing them.  It's a little bit of a pain, but the result works pretty well.

Here, I'm purging any white filament from the hotend after printing the diffuser layer and loading the black filament:

Next, I run the bezel g-code to construct the cells right on top of the diffuser:

The result is a single piece which fits over the 0603 LEDs (on 0.1" centers):

Like the previous experiments with 3D printed bezels at this scale, normal slicers just don't cut it :-) I had to generate the g-code to print these using a python program.  After you get started, though, it's pretty cool what you can do by putting down a few hundred microns of plastic exactly where you want it.

I think I'm going to expand the code to add brackets to mount the bezel to the PCB holes.  More python -> more g-code -> more melted plastic.


bitreaper wrote 11/21/2018 at 22:45 point

I like the "bloom" effect of the white/white bezel.

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Ted Yapo wrote 11/22/2018 at 01:33 point

in person, it looks like a defocused analog oscilloscope - but there's no focus knob!

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bitreaper wrote 11/22/2018 at 01:40 point

Yeah, looks like the old phosphor screens...  Btw, I've used your VEML7700 arduino library, and it's been nice to have.  Thanks for coding that up!

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A. M. Aitken wrote 11/21/2018 at 22:09 point

Are you doing "Life" on that display ;)

That's a really impressive diffuser/bezel result.

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Ted Yapo wrote 11/22/2018 at 01:35 point

yep, it's life

The diffuser works great, but in bright light, the contrast isn't ideal since the white diffuser reflects a lot of ambient light.  I'm going to try to print the whole assembly on top of a green filter next.  If the print will stick to it, that should improve the contrast.

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