geekhack

geekhack Community => Keyboards => Topic started by: schad on Thu, 19 June 2014, 08:30:48

Title: Backlight questions
Post by: schad on Thu, 19 June 2014, 08:30:48
Hi all.  All my Google searches kept sending me here, so I figured I ought to cut out the middle man and ask my questions here directly.

I bought a Logitech G710+ about a week ago.  Well, within 15 minutes of getting it hooked up to my computer, my wife -- who previously told me "More than $40 for a keyboard, are you crazy?" -- simply must have a mechanical keyboard too.  Turns out that the backlighting on the keyboard makes me nauseous, so probably I'm going to give her this keyboard and get a new one for myself.

Background out of the way, here are my questions.

1: The backlight bothers me because I can see it flickering.  In bright ambient light, with the brightness on the backlighting all the way down, it doesn't bother me.  But at night with the room lights off, the only setting that doesn't make me dizzy is "off," which rather defeats the purpose of having a backlit keyboard.  The LEDs seem to be built into the key switches, rather than being done by Logitech.  Am I going to have this problem with every backlit keyboard?

2: Assuming I'm able to have a backlit keyboard, is it possible to (very dimly!) illuminate the borders of the keys, but not the letters?  For example, if I get opaque, blank keycaps on a backlit keyboard, will I see a faint outline around the keys?  I found one guy here who did this, but no pictures of what it looks like in darkness.  Tons of pictures of translucent caps, of course, but I want less light, not more.

3: If #2 works, it seems like there may be keyboards which are better for it than others.  Probably boards with reflective... I don't know what you call it, plates?  And the bigger the gap around keys the more light will escape, so the choice of caps might matter also.  Any specific recommendations, either for ("this keyboard works great!") or against ("definitely don't try it with this keyboard")?

I do want backlighting, so I'm willing to spend a little extra time and money.  But if I can't get it, at least my search will become a whole lot easier!

Appreciate any help you all can offer.
Title: Re: Backlight questions
Post by: Melvang on Thu, 19 June 2014, 08:41:24
Hi all.  All my Google searches kept sending me here, so I figured I ought to cut out the middle man and ask my questions here directly.

I bought a Logitech G710+ about a week ago.  Well, within 15 minutes of getting it hooked up to my computer, my wife -- who previously told me "More than $40 for a keyboard, are you crazy?" -- simply must have a mechanical keyboard too.  Turns out that the backlighting on the keyboard makes me nauseous, so probably I'm going to give her this keyboard and get a new one for myself.

Background out of the way, here are my questions.

1: The backlight bothers me because I can see it flickering.  In bright ambient light, with the brightness on the backlighting all the way down, it doesn't bother me.  But at night with the room lights off, the only setting that doesn't make me dizzy is "off," which rather defeats the purpose of having a backlit keyboard.  The LEDs seem to be built into the key switches, rather than being done by Logitech.  Am I going to have this problem with every backlit keyboard?

2: Assuming I'm able to have a backlit keyboard, is it possible to (very dimly!) illuminate the borders of the keys, but not the letters?  For example, if I get opaque, blank keycaps on a backlit keyboard, will I see a faint outline around the keys?  I found one guy here who did this, but no pictures of what it looks like in darkness.  Tons of pictures of translucent caps, of course, but I want less light, not more.

3: If #2 works, it seems like there may be keyboards which are better for it than others.  Probably boards with reflective... I don't know what you call it, plates?  And the bigger the gap around keys the more light will escape, so the choice of caps might matter also.  Any specific recommendations, either for ("this keyboard works great!") or against ("definitely don't try it with this keyboard")?

I do want backlighting, so I'm willing to spend a little extra time and money.  But if I can't get it, at least my search will become a whole lot easier!

Appreciate any help you all can offer.

1.  Chances are yes.  The flickering I believe is due to PWM style LED driver.  To my knowledge this turns the LEDs on and off very rapidly but not all at once.  What this does is allows the driver to illuminate many more LEDs that what current is available for.

2.  Yes.  Or if the LED's still bother you, you could look into modding your board with EL mat.  I believe it is the parallel wire style of mat that you can cut holes in.  Just get a mat that is big enough to cover the plate, cut holes in it for the switches, set it on top, plug it in and enjoy.  Fair warning though EL mat only comes in a very select few colors and will probably get expensive for a mat that size.  But the since part is that it is a very subtle and even glow.  Just go with mat and not wire.

3.  For the most part all boards will have the same gap between keys.  It is around .030" between the skirt on the caps.  If you do want to block all the light from coming through the caps than my suggestion would be thick black caps either ABS or PBT will work.  If you find a set of caps that you really like that still lets light shine through and you want to stop that, you can probably fix that issue with white, or chrome finger nail polish on the back side of the caps.
Title: Re: Backlight questions
Post by: Grendel on Thu, 19 June 2014, 12:55:22
I had the same problem, I wanted a back-lit board but the PWM stroboscopic effects drive me nuts. Tried the 710+, Corsair K70, Ducky Shine 3, Deck Hassium Pro (in order of most to least annoying) -- they are all unusable for me w/ their lights on. The only off the shelf boards I used that drive the LED's not via PWM are Xarmor U8B's, Deck Legend's, and WASD Code keyboards. First two are out of production and I would stay away from the Xarmor (iOne, eew.) My recommendation would be the WASD Code (http://www.wasdkeyboards.com/index.php/products/code-keyboard.html), very solid board w/ no-nonsense BL.

Edit: forgot to mention -- in the end I gave up on BL, couldn't find the right board (but them I'm VERY picky. ;) The WASD Code Green was pretty close.) Using keycaps w/ good legend contrast works well for me.
Title: Re: Backlight questions
Post by: schad on Sun, 22 June 2014, 12:08:13
Thanks for the feedback, guys.  It sounds like no-backlight is the way to go, and if I want it later, I can add it myself.

The EL pad approach actually appeals to me a lot.  I'm not really a fan of LED backlighting in general: LEDs are just too directional and too bright.  I'd actually come across EL wire for another project I'm looking to do, so I'd even done some reading about it already.  The main downside is that it either requires some circuit-building (which I am not up to) or an external power brick.  But this is for a desktop, so it might actually work out.
Title: Re: Backlight questions
Post by: Melchior on Mon, 23 June 2014, 21:27:49
Yes, EL wire itself requires an inverter circuit.

(not complex just a few common and cheap parts)

Also multi-hundred volt AC lighting is cool! LOL.
Title: Re: Backlight questions
Post by: Melvang on Mon, 23 June 2014, 21:31:17
Yes, EL wire itself requires an inverter circuit.

(not complex just a few common and cheap parts)

Also multi-hundred volt AC lighting is cool! LOL.

EL mat will look much better for keyboard backlighting than wire.  Unless you are using wire under the bottom of the board to light the perimeter of the base.
Title: Re: Backlight questions
Post by: mashby on Mon, 23 June 2014, 21:57:10
What is EL Mat? My google foo is weak. Not finding anything.
Title: Re: Backlight questions
Post by: 0100010 on Mon, 23 June 2014, 22:16:39
Electroluminescent sheet
Title: Re: Backlight questions
Post by: mashby on Tue, 24 June 2014, 09:22:34
Thank you. I found some when I searched for EL Panels - http://www.ellumiglow.com/el-tape/el-panels
Title: Re: Backlight questions
Post by: dorkvader on Tue, 24 June 2014, 21:16:48
I have the same flicker sensitivity too. I dont' get dizzy or nauseous, but it's really annoying. Good to see there are other people who notice as well. FOr a while I only used CRT monitors in 120HZ or faster.

Even my nice custom lightsaver keyboard flickers, so I keep the lights off :(

The T3 BL82 (same company as Deck) also doesn't flicker too badly. Sadly it's 2KRO.
Title: Re: Backlight questions
Post by: mouse.the.lucky.dog on Wed, 25 June 2014, 12:09:04
A warning about the EL stuff--the inverter tends to have a hum. Some people it annoys, others don't care.
Title: Re: Backlight questions
Post by: Melvang on Wed, 25 June 2014, 15:57:23
A warning about the EL stuff--the inverter tends to have a hum. Some people it annoys, others don't care.


And extension cords for between the inverter and the panel generally do not work or will dim the panel.  Due the the panels being hyper sensitive to resistance in the high voltage lines.
Title: Re: Backlight questions
Post by: fleimi on Wed, 25 June 2014, 17:07:42
I find it interesting that some people can sense this kind of flickering. To me, it just looks like the LEDs are constantly powered. Stupid superhumans with their >30fps eyesight
Title: Re: Backlight questions
Post by: Melvang on Wed, 25 June 2014, 19:35:41
While I can't see the flickering on LED's I can see the rainbow effect with white text on black with DLP tech tvs.
Title: Re: Backlight questions
Post by: rowdy on Wed, 25 June 2014, 20:29:40
I find it interesting that some people can sense this kind of flickering. To me, it just looks like the LEDs are constantly powered. Stupid superhumans with their >30fps eyesight

There are a few technologies that exhibit this.  Fluoro tubes, for example.  I cannot see flicker, but one guy here gets so sick with the flickering that we had to remove all the fluoro tubes from his area (which is why I work in semi-darkness btw).

I used to be able to hear high-pitched squealing from CRT monitors back in the day, which no-one else could hear.  I welcomed and embraced the advent of LCD monitors, and am yet to hear one squealing.
Title: Re: Backlight questions
Post by: dorkvader on Thu, 26 June 2014, 09:45:16
I find it interesting that some people can sense this kind of flickering. To me, it just looks like the LEDs are constantly powered. Stupid superhumans with their >30fps eyesight

The flicker threshold of the average person seems to be roughly 50-60 Hz. This number changes of course, depending on the lighting, etc.

Anyway, There's no reason to have such a "slow" PWM circuit on LEDs that people can see flickering. Just up it to a few hundred Hz at least and call it a day.
Title: Re: Backlight questions
Post by: James35 on Fri, 27 June 2014, 15:35:36
I find it interesting that some people can sense this kind of flickering. To me, it just looks like the LEDs are constantly powered. Stupid superhumans with their >30fps eyesight

People are aware of ergonomics, but many aren't aware of flicker until you show them. When I worked at Kodak as a computer IT tech, I showed the Kodak employees about CRT monitor refresh rate.  What I would do is bring up a white background (spreadsheet/document) and told them to hold their eyes still above the monitor. Then they could see the flicker.  I would bump up the refresh rate from the default 60Hz to 85Hz and they were astounded at the difference.  Sad part was, these guys were usually working with white backgrounds all day, and getting unnecessary eye strain / headaches without knowing why.   Needless to say, they were very thankful when I fixed their video card drivers and increased the refresh rate.  I got so good at it, that I could tell you within +/- 5Hz of how fast a monitor's refresh rate was (anywhere between 56 and 120Hz).

Another similar thing that drives me crazy is someone (probably a psychologist) claimed they determined that the human eye can't see more than 24FPS. Since 1927, 24FPS has been the standard for movies until The Hobbit came out at 48FPS in 2012. That's 85 years!  Terrible.  If you watched the Hobbit in the theater AND saw the HFR (high frame rate) version, you can CLEARLY see the difference.  Smooooth. A lot more detail.  Our human eye sees infinite frames per second, so why in the world that someone thought 24 was maximum was completely wrong. I was happy to see the next Hobbit in 2013 was also 48FPS.  I NEVER want to watch a movie at 24FPS again if I have the choice.  I'm glad to hear that Avatar 2 is supposed to be 96FPS!

As for LED backlighting flicker. I think that some manufacturers might do it slightly different than others.  I could see the flicker on my Ducky Shine 3 much worse than the CM Quickfire Rapid-I.  I'm not an electronics expert, but couldn't the voltage be smoothed out in between the PWM board and the LED with a capacitor?
Title: Re: Backlight questions
Post by: Melvang on Fri, 27 June 2014, 17:19:07
I find it interesting that some people can sense this kind of flickering. To me, it just looks like the LEDs are constantly powered. Stupid superhumans with their >30fps eyesight

People are aware of ergonomics, but many aren't aware of flicker until you show them. When I worked at Kodak as a computer IT tech, I showed the Kodak employees about CRT monitor refresh rate.  What I would do is bring up a white background (spreadsheet/document) and told them to hold their eyes still above the monitor. Then they could see the flicker.  I would bump up the refresh rate from the default 60Hz to 85Hz and they were astounded at the difference.  Sad part was, these guys were usually working with white backgrounds all day, and getting unnecessary eye strain / headaches without knowing why.   Needless to say, they were very thankful when I fixed their video card drivers and increased the refresh rate.  I got so good at it, that I could tell you within +/- 5Hz of how fast a monitor's refresh rate was (anywhere between 56 and 120Hz).

Another similar thing that drives me crazy is someone (probably a psychologist) claimed they determined that the human eye can't see more than 24FPS. Since 1927, 24FPS has been the standard for movies until The Hobbit came out at 48FPS in 2012. That's 85 years!  Terrible.  If you watched the Hobbit in the theater AND saw the HFR (high frame rate) version, you can CLEARLY see the difference.  Smooooth. A lot more detail.  Our human eye sees infinite frames per second, so why in the world that someone thought 24 was maximum was completely wrong. I was happy to see the next Hobbit in 2013 was also 48FPS.  I NEVER want to watch a movie at 24FPS again if I have the choice.  I'm glad to hear that Avatar 2 is supposed to be 96FPS!

As for LED backlighting flicker. I think that some manufacturers might do it slightly different than others.  I could see the flicker on my Ducky Shine 3 much worse than the CM Quickfire Rapid-I.  I'm not an electronics expert, but couldn't the voltage be smoothed out in between the PWM board and the LED with a capacitor?

I think what they were referring to was the eye begins to register individual images into motion arount the 24fps range.  At least that is my understanding.