Hammer over membrane switches?

[Daniel Beardsmore]

Which switches do you all consider to be hammer-over-membrane?

I was sure I'd read that Acer switches and Cherry MY switches fall under this category (not just membrane buckling spring), but I can't find any sign of this now. If not, how would those two be classified?

Just wanted to double-check before I miscategorise switches on the wiki :)

[Icarium]

I don't know any but the Model M. And maybe other BS switches like that Sheng one. I think only buckling springs have hammers. At least I don't know of any other switches with somewhat "hammering" parts. HaaTa might have other ideas, though.

Cherry MY have a membrane but a slider instead of a hammer.

[urbanus]

Cherry MY have a membrane but a slider instead of a hammer.

No, the white slider doesn't come in contact with the membrane.

The leaf spring in MY is roughly equivalent to the buckling spring hammer, except that the BS hammer rocks/moves whereas the MY leaf spring flexes. Similarly with the helical spring, except that the BS spring compresses and buckles whereas the MY spring compresses and places pressure on the leaf spring.

I would normally think of a hammer as a moving part that strikes another (c.f. piano). With MY, the leaf spring is not free-moving (it's attached to the bottom of the key) and it flexes and pressures the membrane, rather than striking it. Is that really a "hammer"?

[Icarium]

Cherry MY have a membrane but a slider instead of a hammer.

No, the white slider doesn't come in contact with the membrane.

So they do have a slider? :p

Otherwise we agree, it just isn't hammer like.

[Daniel Beardsmore]

So, how should I class/categorise Acer and MY then?

[Icarium]

It's slider over spring over membrane. I'm not sure what your categories are or what the problem is.

[Daniel Beardsmore]

I'm trying to describe and classify them in the wiki. Cherry ML and MX, ALPS etc are classified as metal contact switches. Cherry MY and Acer are something else, but I don't have a succinct term by which to classify them and any other switches of that type. For some reason I thought they were called hammer-over-membrane, but that's probably a misunderstanding on my part.

[Icarium]

You could call them Beardsmore switches since they don't have, it seems, an established name.

Or you could just call them slider-over-membrane.

[Daniel Beardsmore]

Slider over membrane covers normal rubberdomes though – plenty of older rubberdome boards had sliders, including U mount sliders. Yes you could polish a turd by putting SP doubleshots onto an old rubberdome board :)

It's not the slider I'm querying, it's the doobrey that depresses the membrane. It's not a hammer, so what is it?

[Icarium]

Well, it's a spring. :p

[JBert]

Cherry MY and Acer are something else, but I don't have a succinct term by which to classify them and any other switches of that type.

Do they need a succinct term? Just explain how it works, and then refer to them as Cherry MY. If you want to have a shorter version of it, try "spring tactility + membrane contact switch".

Also note that the Acer and MY work differently. If I read it right, the Acer switch has a slider which contains a spring pushing down on another slider (or "hammer") to push the membrane contacts. Cherry MY has a helical spring which sits between the slider and housing, it doesn't come into contact with anything else. Once the slider is depressed halfway down, it will reach and bend the leaf spring which in turn pushes the membrane.

[Daniel Beardsmore]

Cherry MY and Acer are something else, but I don't have a succinct term by which to classify them and any other switches of that type.

Do they need a succinct term? Just explain how it works …

OK, so in the wiki, you'd have these switches sit outside of any subcategories? You would have them all be unclassifiable, unique designs?

[bhtooefr]

Well, they can be classified as membrane-based (I'd have all membrane-based switches be a member of that category, even if they also fit in a more specific category), at least.

[Icarium]

He suggested calling them MY-like that would be your category. You could also call them spring-over-foil or slider-over-foil, just decide something.

[JBert]

It's not as if they're orphaned if some other category doesn't fit. They are already under "linear" or "tactile", and somebody added both to "membrane switches".

[Daniel Beardsmore]

Cherry MY and Acer are something else, but I don't have a succinct term by which to classify them and any other switches of that type.

Do they need a succinct term? Just explain how it works …[/quote]

I could if I could find diagrams for the switches, though I hate Acer switches enough that I wouldn't lose any sleep over breaking mine if I took apart some of the switches incorrectly … (I find it curious that many people consider Acer switches to be light and delicate – I find them stupidly stiff and awkward.)

A succinct term is useful for introductory paragraphs so that more knowledgeable readers know what you're referring to, and categories help to keep lists of items tidy and accessible; there's a lot of tidying needed still.

It's not as if they're orphaned if some other category doesn't fit. They are already under "linear" or "tactile", and somebody added both to "membrane switches".

I added the Acer switch to the membrane switches category from the start – no-one has edited the page since I created it.

I've changed the description to "spring-over-membrane" for now as it gets rid of the error and it removes one item from the list of wanted pages. Calling them "membrane" is only a partial classification because membrane only means one thing: cannot accept diodes. That's it. The presence of a membrane has no relevance to keyfeel. One person said that you can feel the membrane in Acer switches, but I certainly can't – they just feel like XM Alps.

[JBert]

Oh, that was you. Well, keep up the good work then!

You are right about the keyfeel, people seem to make up the weirdest things.

Membrane can imply lots of things though: spill resistance (they could resist liquids better than PCB-mounted discrete switches, as long as it doesn't get between the layers), zero moddability (although some have tried with silver pens) and cost-effective roll-over (the Microsoft X4 has a membrane AND > KRO thanks to a trick with voltage dividers).

[Daniel Beardsmore]

I did find an article here at DT where Findecanor described them as "hammer over membrane". I've added a photo to the [wiki]Acer switch[/wiki] page showing the switch from below as well as extended the definition now that I've opened up the keyboard (after all, some people actually like these switches). "Hammer" really isn't far off if not actually correct: the main spring is anchored to a small plastic hammer that strikes the membrane based solely on the build up of pressure in the spring. There is no hard connection between the slider and the membrane.

It looks like there isn't quite enough space within the hammer to fit the legs of an LED into the gap freed up by not having the contact mechanism.

(I decided I didn't care if I broke the keyboard, so I dismantled it. It's possible I've broken the connection between the membrane and the controller now ;-)