B3F-4055 switch bounce

[Ioannis]

Maybe you can solder a wire on the SR25 metals. With patience I have to say...

Ioannis

[Demon]

I'm thinking of leaving open pads under the 2 crimps on both sides.

[Demon]

Maybe you can solder a wire on the SR25 metals. With patience I have to say...

Ioannis

I was shopping for laser engravers to etch white text on black PLA and saw that a machine to cut thin steel plate would be expensive.

I started thinking of glueing aluminium foil onto a thin plastic sheet, and then using the mini-CNC to mill the sheet to fit inside the enclosure cover. That way the metal switches would touch against the aluminium foil, and then ground that. It might act as a EMI shield inwards and outwards, maybe.

Anything thin and conductive could do the job, not just aluminium. It's just a matter of finding something that is workable, and inexpensive, aluminium foil is just so readily available here.


EDIT: I can't believe I didn't think of this right away. Single-sided copper-clad PCBs are readily available and can be milled to fit. I just need to find a cheap and reliable source (haven't checked yet).

[Demon]

I just saw copper mesh on Amazon, which got me thinking about going even much simpler. Just snaking a bare copper wire along the inside of the enclosure cover. I only have to touch the metal surface on the switches.

No machining, just hot glue and a connector at the end to bring it back to GND. Cheap and easy implemented. I just won't be getting any structural strength or shielding. :/

[Ioannis]

In general the SR25 and other alike pots etc, are supposed to be mounted on a metal surface which is grounded by default.

Maybe you can do the same. On the plastic enclosure have a thin aluminum face, cut in you CNC. Then you may do also lettering and drop silkscreen ink in the engraving. The latter will require thicker metal sheet though.

Ioannis

[Demon]

I'm leaning more towards snaking a bare wire along the inside of the enclosure cover. It'll do the job of grounding all the metal components, and it's cheap and without serious machine labour.

I've also been thinking a lot about how to get lettering on the front. My first idea was engraving acrylic sheets and backlighting with LEDs, but I've already got a LOT on my plate as it is.

So I found out you can etch into PLA without any special hardware or material. An diode laser engraver "should' do the job (I need to do more research).

It's a matter of testing settings. This guy is using a 30 watt machine at 20%; that's only 6 watts. I'm looking at 20 watt machines, since 10 watts doesn't leave a wide margin.

[Ioannis]

And how exactly are the lettering painted white on the black PLA?

This looks very nice.

Ioannis

[Demon]

Something about removing pigment and exposing the original material. Apparently PLA is white with added dies.

There's other explanations on the web like "overheated air bubbles get trapped in the material thus changing the colour", but this one seems to be the most accepted. It's possible that they're both correct to some degree. I just wouldn't bet my life on the scientific reason just yet. As long as it works, that's all I care.

I always thought they used a two-layer material; black exterior over base white. A laser would remove the black layer exposing the white base. Something like what I bought to try out on the mini-CNC:

https://www.amazon.ca/Engraving-Doub...7QT93LN9/?th=1

I haven't tried them yet. They're a bit expensive, but the white base is semi-transparent; you can shine LEDs through them and create text with backlight.