Author Topic: What kind of SMD LEDs to use with SMD-LED-compatible switches? (Read 19004 times)

Eszett · « **on:** Sun, 20 November 2016, 05:17:53 »

Hi.. what kind of LED package I have to use when I want to fit SMD LEDs in those SMD-LED-compatible switches, made by Cherry/Gateron? And what exact position must they have in relation to the switches center?

SKD · « **Reply #1 on:** Sun, 20 November 2016, 06:22:18 »

What board are you using?

Eszett · « **Reply #2 on:** Sun, 20 November 2016, 15:16:34 »

I'd like to build my own PCB for it. Cherry writes "CHERRY MX1A... ... MX switch variant optimised for use with SMD LEDs (RGB or single colour)" but the datasheet gives no info about the dimensions of the LED slot, and what kind of SMD LEDs shall be used. http://www.cherry.de/cid/keymodules_CHERRY_MX1A-LxxA_B.htm?

deadall127 · « **Reply #3 on:** Sun, 20 November 2016, 15:24:21 »

I think any kind of SMD leds will works, the most common is 5050

Eszett · « **Reply #4 on:** Sun, 20 November 2016, 15:54:02 »

Quote from: deadall127 on Sun, 20 November 2016, 15:24:21

I think any kind of SMD leds will works, the most common is 5050

Don't you think the SMD LEDs will collide with the switch housing if they dont fit through the Switch's LED slot?

SKD · « **Reply #5 on:** Mon, 21 November 2016, 07:45:28 »

Quote from: Eszett on Sun, 20 November 2016, 15:16:34

I'd like to build my own PCB for it. Cherry writes "CHERRY MX1A... ... MX switch variant optimised for use with SMD LEDs (RGB or single colour)" but the datasheet gives no info about the dimensions of the LED slot, and what kind of SMD LEDs shall be used. http://www.cherry.de/cid/keymodules_CHERRY_MX1A-LxxA_B.htm?

The LED gap on my gateron switches are about 3mm x9.5mm. Cherry ones should be similar?

SKD · « **Reply #6 on:** Mon, 21 November 2016, 07:54:48 »

Quote from: Eszett on Sun, 20 November 2016, 15:54:02

Quote from: deadall127 on Sun, 20 November 2016, 15:24:21
I think any kind of SMD leds will works, the most common is 5050

Don't you think the SMD LEDs will collide with the switch housing if they dont fit through the Switch's LED slot?

Double post soz.

There's a gap on the side of the switch housing on them smd led compatible switches to take into account the height of the smd leds. It shouldn't collide. I'm at work at the moment so I can't get a photo.

kolec94 · « **Reply #7 on:** Mon, 21 November 2016, 09:09:47 »

cherry mx rgb switches and some gaterons support rgb smd led's
you need gaterons in white housings

deadall127 · « **Reply #8 on:** Mon, 21 November 2016, 09:34:22 »

Quote from: SKD on Mon, 21 November 2016, 07:54:48

Quote from: Eszett on Sun, 20 November 2016, 15:54:02
Quote from: deadall127 on Sun, 20 November 2016, 15:24:21
I think any kind of SMD leds will works, the most common is 5050

Don't you think the SMD LEDs will collide with the switch housing if they dont fit through the Switch's LED slot?

Double post soz.

There's a gap on the side of the switch housing on them smd led compatible switches to take into account the height of the smd leds. It shouldn't collide. I'm at work at the moment so I can't get a photo.

+1 I think so too

Eszett · « **Reply #9 on:** Tue, 22 November 2016, 00:19:05 »

I'm pretty sure that any SMD LED wont fit, if I took a larger it will collide with the switch housing,. So my question is which package will fit?

SKD · « **Reply #10 on:** Tue, 22 November 2016, 02:17:21 »

SMD LED compatible switch, a SMD LED. See that gap? As long as the LED sits flat on the PCB, or even 1-2mm raised from the PCB it will work. I think these smd leds I have are 3528 ones.

pomk · « **Reply #11 on:** Tue, 22 November 2016, 06:11:14 »

Looking at the switch, the cavity for the SMD led is pretty large. I did some rough measurements, rounding down, and came up with this:

What kind of SMD LEDs to use with SMD-LED-compatible switches?

edit: this is a gateron SMD switch.
On cherry site they have a picture from the underside, and the space looks like a 1,8mm square, centered between the led pins. It is probably easier to just bottom mount the SMD leds and not worry about positioning and clearance that much. That way you can also use switches like the zealios or frosted gaterons without problems.

Eszett · « **Reply #12 on:** Tue, 22 November 2016, 10:41:49 »

Excellent answer by SKD and pomk, thanks for the dimensions! However, I wonder abit: if the light can merely pass through the slot isn't that wasting a alot of light? Wouldnt it be better then to have SMD LED's that actually fit into the slow to reach out of the switch housing?

SKD · « **Reply #13 on:** Tue, 22 November 2016, 11:10:30 »

Internal reflection should work pretty well. But a clear house bottom would be ideal, which I don't think they exist.

kolec94 · « **Reply #14 on:** Tue, 22 November 2016, 11:18:15 »

Quote from: Eszett on Tue, 22 November 2016, 10:41:49

Excellent answer by SKD and pomk, thanks for the dimensions! However, I wonder abit: if the light can merely pass through the slot isn't that wasting a alot of light? Wouldnt it be better then to have SMD LED's that actually fit into the slow to reach out of the switch housing?
(Attachment Link)

yes but try to find a 3mm rgb led

Quote from: SKD on Tue, 22 November 2016, 11:10:30

Internal reflection should work pretty well. But a clear house bottom would be ideal, which I don't think they exist.

there are clear key switch housing and also milky versions

pomk · « **Reply #15 on:** Tue, 22 November 2016, 12:11:46 »

In the gateron switches the wall are off-white colour, and so reflect something like 70% of light in a diffused manner. Also the distribution of light from the SMD led is not even, but rather directed to the top. You can check the spatial distribution chart of any led you wish to use.

SKD · « **Reply #16 on:** Tue, 22 November 2016, 12:40:18 »

Quote from: kolec94 on Tue, 22 November 2016, 11:18:15

Quote from: Eszett on Tue, 22 November 2016, 10:41:49
Excellent answer by SKD and pomk, thanks for the dimensions! However, I wonder abit: if the light can merely pass through the slot isn't that wasting a alot of light? Wouldnt it be better then to have SMD LED's that actually fit into the slow to reach out of the switch housing?
(Attachment Link)
yes but try to find a 3mm rgb led

Quote from: SKD on Tue, 22 November 2016, 11:10:30
Internal reflection should work pretty well. But a clear house bottom would be ideal, which I don't think they exist.
there are clear key switch housing and also milky versions

There is? I haven't been able to find any clear top/bottom switches that are also smd led compatible. Where do I find this?

kolec94 · « **Reply #17 on:** Tue, 22 November 2016, 20:06:57 »

Quote from: SKD on Tue, 22 November 2016, 12:40:18

Quote from: kolec94 on Tue, 22 November 2016, 11:18:15
Quote from: Eszett on Tue, 22 November 2016, 10:41:49
Excellent answer by SKD and pomk, thanks for the dimensions! However, I wonder abit: if the light can merely pass through the slot isn't that wasting a alot of light? Wouldnt it be better then to have SMD LED's that actually fit into the slow to reach out of the switch housing?
(Attachment Link)
yes but try to find a 3mm rgb led

Quote from: SKD on Tue, 22 November 2016, 11:10:30
Internal reflection should work pretty well. But a clear house bottom would be ideal, which I don't think they exist.
there are clear key switch housing and also milky versions

There is? I haven't been able to find any clear top/bottom switches that are also smd led compatible. Where do I find this?

https://www.massdrop.com/buy/smd-led-compatible-gateron-switches
or just cherry mx rgb switches

SKD · « **Reply #18 on:** Wed, 23 November 2016, 00:35:47 »

Oh I have those already. I meant both switch top and bottom housing are clear, like zealios but smd compatible.

Eszett · « **Reply #19 on:** Wed, 23 November 2016, 02:38:41 »

OK let me recap: SMD LED compatible switches feature a little cavity below the switch bottom housing, that give room for SMD LEDs. However - and I think we agree with that - this makes only sense, if the switch *bottom housing* is transparent, to let the light pass through as much as possible. So why have the SMD LED compatible switches no transparent switch bottom housings, that is hard to understand!?

tobsn · « **Reply #20 on:** Wed, 23 November 2016, 09:22:15 »

Front soldered RGB LEDs with transparent top housing switches:
https://world.taobao.com/item/536572743977.htm?spm=a312a.7700714.0.0.54i7xT#detail

(at least it appears that way)

pomk · « **Reply #21 on:** Wed, 23 November 2016, 10:02:47 »

Quote from: Eszett on Wed, 23 November 2016, 02:38:41

OK let me recap: SMD LED compatible switches feature a little cavity below the switch bottom housing, that give room for SMD LEDs. However - and I think we agree with that - this makes only sense, if the switch *bottom housing* is transparent, to let the light pass through as much as possible. So why have the SMD LED compatible switches no transparent switch bottom housings, that is hard to understand!?

I'm not sure if I understand the problem. I should probably take some pictures from the underside of the gateron SMD swithch to show how little the bottom housing actually blocks light. Cherry SMD switches have clear bottom and top housings, but the opening/cavity is much smaller.

edit: actually massdrop has a pretty ok picture from the underside as well. As you can see, most of the opening is either uncovered or covered by the clear top housing only.

deadall127 · « **Reply #22 on:** Thu, 24 November 2016, 02:37:14 »

that's why I will use THT RGB LEDs for my keyboards, 2x5x5mm package seems working fine

Eszett · « **Reply #23 on:** Wed, 14 December 2016, 00:28:27 »

Quote

Cherry SMD switches have clear bottom and top housings, but the opening/cavity is much smaller.

@pomk As far as I can see it Cherry's RGB switches don't have a translucent bottom housing. I don't understand how that matches Cherry's description "Optimized for SMD LEDs".

But that's going abit far from my original question, which was: What kind of SMD LEDs fit under those RGB switches. The answers were 5050, and 3528.

pomk · « **Reply #24 on:** Wed, 14 December 2016, 04:29:58 »

Sure looks translucent to me

5050 is 5mm x 5mm, there is no way it will fit inside the cavity in the above picture and I doubt that 3528 as any higher chance. Where did you find this information?

Eszett · « **Reply #25 on:** Thu, 15 December 2016, 01:28:34 »

@pomk deadall and SKD wrote it in this thread ...

pomk · « **Reply #26 on:** Thu, 15 December 2016, 05:15:30 »

Ah, sorry. They, or any other that fits in the cavity diagram I made, should fit under gateron smd switches. I thought you were interested in the cherry rgb switches and their clear bottom housings with considerably smaller cavities.

At least the following should work as well: 4014, 3535, 3030, 3020, 3014, 2835, 1206 and 1104. 1104 would probably work with cherry rgb as well.

Most if not all boards that feature cherry rgb switches actually use bottom mounted smd leds and those would work with gateron, cherry, zealios, matias etc. as long as the bottom housing can pass light.

deadall127 · « **Reply #27 on:** Fri, 16 December 2016, 00:26:25 »

Quote from: Eszett on Thu, 15 December 2016, 01:28:34

@pomk deadall and SKD wrote it in this thread ...

eh? I said THT (through-hole technology) not SMD (surface mounted device)

vvp · « **Reply #28 on:** Fri, 16 December 2016, 05:31:00 »

If somebody buys the Gateron switches with a space for SMD LEDs in the bottom housing then please measure the dimensions precisely with calipers and post the data. Or even better, if somebody has a data sheet for the switch then post the link, please.

pomk · « **Reply #29 on:** Fri, 16 December 2016, 06:08:55 »

Quote from: vvp on Fri, 16 December 2016, 05:31:00

If somebody buys the Gateron switches with a space for SMD LEDs in the bottom housing then please measure the dimensions precisely with calipers and post the data. Or even better, if somebody has a data sheet for the switch then post the link, please.

I have them at hand, but no calipers.

If someone plans on making a rgb pcb, I'd suggest just using bottom mounted smd leds to get rid of any and all compatibility problems.

vvp · « **Reply #30 on:** Fri, 16 December 2016, 06:48:10 »

I was thinking along the lines whether I can find an RGB SMD LED which would have a tight fit into the space. If yes then I could use them even without a PCB. It requires a bit of skills to solder an enameled wire. But it is not hard if the wire diameter is small. And enameled wire is probably the most easy thing how to quickly hand-wire a keyboard. Since keyboard matrix is very simple an regular, it is quicker to just hand-wire prototypes than even trying to design a PCB. Maybe swill will extend his keyboard plate tool to a PCB making tool too though

SKD · « **Reply #31 on:** Fri, 16 December 2016, 07:12:43 »

Quote from: SKD on Mon, 21 November 2016, 07:45:28

Quote from: Eszett on Sun, 20 November 2016, 15:16:34
I'd like to build my own PCB for it. Cherry writes "CHERRY MX1A... ... MX switch variant optimised for use with SMD LEDs (RGB or single colour)" but the datasheet gives no info about the dimensions of the LED slot, and what kind of SMD LEDs shall be used. http://www.cherry.de/cid/keymodules_CHERRY_MX1A-LxxA_B.htm?

The LED gap on my gateron switches are about 3mm x9.5mm. Cherry ones should be similar?

Quote from: vvp on Fri, 16 December 2016, 05:31:00

If somebody buys the Gateron switches with a space for SMD LEDs in the bottom housing then please measure the dimensions precisely with calipers and post the data. Or even better, if somebody has a data sheet for the switch then post the link, please.

pomk · « **Reply #32 on:** Fri, 16 December 2016, 09:29:28 »

Yes, actually a bit larger than that. Important thing to note is that cherry rgb switches are nothing alike.

vvp · « **Reply #33 on:** Fri, 16 December 2016, 09:56:50 »

Yes, I know. Cherry smd switches are useless for my experiment. From what I have seen Gaterons SMD LED compatible are the only option where it makes sense to try it. I need to fit a large SMD diode there so that it is still easy to solder. Well, a through hole LED would be better but through hole RGB LEDs are huge (typically Ø 5mm bulbs - that is too much). I did not see any through hole RGB LED "bricks" with dimensions around 3x8x4.5 mm.

pomk · « **Reply #34 on:** Fri, 16 December 2016, 12:58:06 »

Zeal sells some, but at a steep price compared to smd ones.

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Author Topic: What kind of SMD LEDs to use with SMD-LED-compatible switches? (Read 19004 times)