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geekhack Projects => Making Stuff Together! => Topic started by: metalliqaz on Sun, 29 March 2015, 00:09:29

Title: Violet/ultraviolet LEDs on keyboards
Post by: metalliqaz on Sun, 29 March 2015, 00:09:29: Has anyone actually installed violet or UV LEDs on their keyboards? If so, please let me know how it worked out.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Evo_Spec on Sun, 29 March 2015, 00:27:02: I'm curious about this too as i want some purple LED's on my board but i'm curious if the UV will damage the caps over time.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Zeal on Sun, 29 March 2015, 00:46:28: UV LEDs are really dim. I've got some 1.8mm ones. :/

I can't speak about yellowing of keycaps though. I know that Hoff used 3mm UV LEDs for his previous GON build.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: metalliqaz on Sun, 29 March 2015, 00:55:08: Quote from: Zeal on Sun, 29 March 2015, 00:46:28
UV LEDs are really dim. I've got some 1.8mm ones. :/

I can't speak about yellowing of keycaps though. I know that Hoff used 3mm UV LEDs for his previous GON build.

Ah, very good to know! If they are truly dim then they won't make good backlights. I suppose smaller resistors could be used to attempt to crank up the current, within reason.

I'm thinking about 405nm LEDs for a new build. They were very expensive but I decided to just pull the trigger anyway. If I don't use them then they will find a home in my electronics kit.

As for the yellowing of caps, that doesn't worry me at all. An LED couldn't possibly match the UV emission of the Sun, and my keyboard has a decent view out the window every single day.

I've got to find a photo of this board you speak of. :)
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Zeal on Sun, 29 March 2015, 00:59:55: Quote from: metalliqaz on Sun, 29 March 2015, 00:55:08
Quote from: Zeal on Sun, 29 March 2015, 00:46:28
UV LEDs are really dim. I've got some 1.8mm ones. :/

I can't speak about yellowing of keycaps though. I know that Hoff used 3mm UV LEDs for his previous GON build.

Ah, very good to know! If they are truly dim then they won't make good backlights. I suppose smaller resistors could be used to attempt to crank up the current, within reason.

I'm thinking about 405nm LEDs for a new build. They were very expensive but I decided to just pull the trigger anyway. If I don't use them then they will find a home in my electronics kit.

As for the yellowing of caps, that doesn't worry me at all. An LED couldn't possibly match the UV emission of the Sun, and my keyboard has a decent view out the window every single day.

I've got to find a photo of this board you speak of. :)

https://geekhack.org/index.php?topic=35864.msg1416004#msg1416004

and 2 posts down. I do have to say that 3mm UV LEDs do seem brighter (to be expected).
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: metalliqaz on Sun, 29 March 2015, 01:02:03: hehe, I was just coming back to post that link.

That purple shade over the orange... hnnnng I think it looks awesome and I'm excited to experiment with it.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Evo_Spec on Sun, 29 March 2015, 03:01:03: Let me know how this turns out, i might go with dark pink LED's if the white led's i have planned don't turn out well.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: nightdriver on Sun, 29 March 2015, 03:05:46: i'm really curious how well these work with glow in the dark keycaps. seems like you could potentially get a really even glow this way.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Findecanor on Sun, 29 March 2015, 06:24:09: An electronics retailer once told me that UV LEDs emit purple light on purpose to warn the user that it is on, so that he won't look directly into it for too long and damage his eyes.
Other people have contested me on it when I have retold it, though. The truth should be in the LED's data sheet.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: metalliqaz on Sun, 29 March 2015, 08:28:44: If the LED adheres to its spec and centers the light around 400nm, then they should be safe. Humans can see down to about 390nm.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Thechemist on Sat, 18 April 2015, 23:37:06: Quote from: metalliqaz on Sun, 29 March 2015, 00:09:29
Has anyone actually installed violet or UV LEDs on their keyboards? If so, please let me know how it worked out.

Poker2, used 2x3x4 UV leds, changed stock resistors to 68ohm.

(http://i.imgur.com/u53Vrn1.jpg)
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: dashing_girlboy on Sun, 19 April 2015, 08:03:23: Quote from: Thechemist on Sat, 18 April 2015, 23:37:06
Poker2, used 2x3x4 UV leds, changed stock resistors to 68ohm.

Show Image
(http://i.imgur.com/u53Vrn1.jpg)

looking at that hurts my eyes.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Thechemist on Sun, 19 April 2015, 09:25:49: Quote from: dashing_girlboy on Sun, 19 April 2015, 08:03:23
Quote from: Thechemist on Sat, 18 April 2015, 23:37:06
Poker2, used 2x3x4 UV leds, changed stock resistors to 68ohm.

Show Image
(http://i.imgur.com/u53Vrn1.jpg)

looking at that hurts my eyes.

At max brightness setting without keycaps looking at the leds can be intense for sure. It isn't as bad on medium setting.

It is psykael (https://geekhack.org/index.php?action=profile;u=40452)'s poker 2, maybe he can let you know how intense it it with keycaps on if he still has it.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: tufty on Sun, 19 April 2015, 10:22:28: Quote from: Thechemist on Sun, 19 April 2015, 09:25:49
At max brightness setting without keycaps looking at the leds can be intense for sure. It isn't as bad on medium setting.

It is psykael (https://geekhack.org/index.php?action=profile;u=40452)'s poker 2, maybe he can let you know how intense it it with keycaps on if he ~~still has it~~ can still see.
FTFY. HTH. HAND.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: metalliqaz on Sun, 19 April 2015, 15:45:20: 68 ohm is way too small. Violet LEDs have a typical forward voltage of 3.3V. Assuming the Poker is using USB 5V, that's 5-3.3 = 1.7V across the resistor. I = V/R = 1.7/68 = 25mA current per LED. 25mA x 61 switches = 1525mA. The USB spec allows 500mA per device. You're drawing way too much current and it's probably not safe.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Thechemist on Mon, 20 April 2015, 05:31:23: Quote from: metalliqaz on Sun, 19 April 2015, 15:45:20
68 ohm is way too small. Violet LEDs have a typical forward voltage of 3.3V. Assuming the Poker is using USB 5V, that's 5-3.3 = 1.7V across the resistor. I = V/R = 1.7/68 = 25mA current per LED. 25mA x 61 switches = 1525mA. The USB spec allows 500mA per device. You're drawing way too much current and it's probably not safe.

Don't you worry about the current draw, I tested it with my DMM and it wasn't nowhere near that. ;)
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: JaccoW on Mon, 20 April 2015, 06:15:48: Quote from: nightdriver on Sun, 29 March 2015, 03:05:46
i'm really curious how well these work with glow in the dark keycaps. seems like you could potentially get a really even glow this way.
Really depends on the GID material used.
I made some pics and a video with the Out of the Vault - series II (https://geekhack.org/index.php?topic=66851.msg1677730#msg1677730) caps.

(http://i.imgur.com/6OpyWqG.jpg)
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: nightdriver on Mon, 20 April 2015, 21:59:22: thanks man, that's exactly what i wanted to see!
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Skechup on Tue, 21 April 2015, 13:35:41: I do think that UV lights could really be nice if you were in the dark. A nice purple glow under a glow in the dark green would make the keyboard look awesome at night, even make the keyboard more sci-fi!
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: Axollott on Tue, 21 April 2015, 13:39:49: Wouldn't this be generally detrimental for your health? (Eyes, skin)
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: metalliqaz on Tue, 21 April 2015, 14:24:27: Quote from: Axollott on Tue, 21 April 2015, 13:39:49
Wouldn't this be generally detrimental for your health? (Eyes, skin)

Not really, for two reasons. First, although the Sun's UV rays are dangerous, the energy emission from a 2x3mm LED is nowhere near as powerful. Second, LEDs actually have fairly narrow spectrum, and these LEDs are centered at about 400nm, which is actually visible light.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: metalliqaz on Fri, 24 April 2015, 22:23:58: Quote from: Zeal on Sun, 29 March 2015, 00:46:28
UV LEDs are really dim. I've got some 1.8mm ones. :/

I can't speak about yellowing of keycaps though. I know that Hoff used 3mm UV LEDs for his previous GON build.

I bought 100 off ebay for the absurd price of $20, and you're absolutely right. They are incredibly dim. I'm disappointed. I was really looking forward to a violet on white color scheme.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: nightdriver on Mon, 27 April 2015, 14:39:18: Quote from: metalliqaz on Fri, 24 April 2015, 22:23:58
I bought 100 off ebay for the absurd price of $20, and you're absolutely right. They are incredibly dim. I'm disappointed. I was really looking forward to a violet on white color scheme.

are you sure they're actually dim? they might be putting off a normal amount of light that is simply outside of your visual range.
Title: Re: Violet/ultraviolet LEDs on keyboards
Post by: metalliqaz on Mon, 27 April 2015, 14:51:06: Quote from: nightdriver on Mon, 27 April 2015, 14:39:18
Quote from: metalliqaz on Fri, 24 April 2015, 22:23:58
I bought 100 off ebay for the absurd price of $20, and you're absolutely right. They are incredibly dim. I'm disappointed. I was really looking forward to a violet on white color scheme.

are you sure they're actually dim? they might be putting off a normal amount of light that is simply outside of your visual range.

As I already pointed out, the LEDs are rated 400-405 nm, which is within the human visible spectrum of 390-700 nm (https://en.wikipedia.org/wiki/Visible_spectrum). Although it's possible that some of the light is too low to see, something like 90% of it should be greater than 390nm.

I suspect that the real problem is a combination of the following:
(1) Cheap-ass parts from Shenzhen
(2) The longer the wavelength, the greater the energy. The lumen/watt ratio (https://en.wikipedia.org/wiki/Light-emitting_diode#Efficiency_and_operational_parameters) for violet is very low.

I think I'm going to go with Pink, instead of Violet. I also have an interesting "Warm white" set of LEDs that I might use. They look pretty good.