B3F-4055 switch bounce

[Ioannis]

Well we expected the BK screenshot response. That is what a good switch bounce should be!

The Fnirsi I guess is either for the recycle bin or has some settings to smooth out the ripple so much that looks like a perfect rect wave.

The SR25 switch, depending on their oxidation state, since the contacts are very much exposed, is normal to have such a behaviour.

Ioannis

[Demon]

...The Fnirsi I guess is either for the recycle bin or has some settings to smooth out the ripple so much that looks like a perfect rect wave....

It's a toy to help teach electronics, nothing more. I'm starting my first return to AliExpress, along with those 3 DMMs that I tried out. I'll see how that goes.

EDIT: I was wrong about this device (next post).

...The SR25 switch, depending on their oxidation state, since the contacts are very much exposed, is normal to have such a behaviour.

Ioannis

This one is brand new though; straight from the manufacturer 2 months ago.

Turns out this was caused by me touching the metal shaft. As soon as I installed a knob, that erratic bounce has mostly gone away. There's still a slight bounce, but nothing so drastic.

It did show to me though that the chinesium scope is useless to analyse signals adequately.

[Ioannis]

If any actuator has metalic case, it is wise that case to be earthed. Metals tend to work like touch sensors or antennas if not properly earthed.

Ioannis

[Demon]

Turns out it helps if you use a device properly, who knew.

The edge can be controlled by the little icon at top left, and SINGLE mode stops updating once triggered (you have to press RUN to reset).

I accelerated the sweep rate, which helped detect some noise but at least it's matching the old scope now.




It does have a few seriously good qualities: it's small, easy to deploy, and not overly complicated. Granted, the screen is small, but at least it can serve as a confirmation of what I see on the BK 1560.

One slight drawback, it seems to lag after a few minutes. It's as if internal storage has a problem managing all the data it accumulates. It gets progressively slower, it's very evident when you press the buttons (the beep gets progressively slower in response).

Still, it's not a bad buy. I'm definitely getting one with a larger display screen later.

[Demon]

If any actuator has metalic case, it is wise that case to be earthed. Metals tend to work like touch sensors or antennas if not properly earthed.

Ioannis

The MR0102 toggle on the right has a support bracket with 4 pins. I can easily ground those.

The SR25 SP4T on the left has no such pins.




I suppose I could pass an eyelet connector over the shaft and fix with a nut and then ground the wire to the PCB mounting screws. I have about 1cm of room under the knob; more than plenty for the plastic enclosure.

That will be a concern on the RV17 rotary pot; the shaft is short and I don't have much thread space. :/

[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. :/