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"Red is Dead" Optical Mice LED Change

A reader sent us the HOWTO for changing that red LED on your fancy-pants new optical mouse to blue - or, I suppose any other color. I think I'm fine with what I've got - although, the glass tops on tables does make using optical mice a pain there.

80 of 490 comments (clear)

  1. what about ultra-violet? by dirvish · · Score: 3, Interesting

    Can you use a black light?

    1. Re:what about ultra-violet? by Anonymous Coward · · Score: 3, Informative

      UV LED light output sucks right now. There are severe materials limitations in their construction. However, if you had a bright enough UV LED, it should be possible. Just don't use IR. Si is transparent to IR, and this is most likely what the detector is made out of.

    2. Re:what about ultra-violet? by grub · · Score: 5, Funny


      Yeah, that would be smart. All over the world geeks would be getting major sunburns on their right palms. :P

      --
      Trolling is a art,
    3. Re:what about ultra-violet? by Angry+White+Guy · · Score: 4, Funny

      Goes with the friction burns on their left palms.

      Oh well, Karma suicide for a good joke....

      --
      You think that I'm crazy, you should see this guy!
    4. Re:what about ultra-violet? by binaryDigit · · Score: 5, Funny

      Yeah, that would be smart. All over the world geeks would be getting major sunburns on their right palms. :P

      Thereby ruining their sex lives.

    5. Re:what about ultra-violet? by drinkypoo · · Score: 3, Funny

      As opposed to the usual friction burns.

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
  2. logitech is blue... by b_pretender · · Score: 5, Interesting
    When I bought my Logitech optical a 1.5 years ago, I stopped at RadioShack on the way home to pick up a blue LED. I was planning to change it first thing when I got home.

    However, upon pluggin my mouse into the computer, the logitech logo and mouse in general glowed blue!!! I was happy. Although the LED on the bottom was red, they had an *extra* LED that was blue for the logo and the *glowing* plastic. That made my day and it involved NO soldering.

    1. Re:logitech is blue... by Wiseazz · · Score: 3, Interesting

      I'm looking at my Microsoft optical now... it looks like it also has a seperate cosmetic led for the logo on the back... I may just try swithcing that out instead of risking the one used for tracking (there may just be one... I haven't taken it apart to check).

      An optical mouse is still a little expensive for me to experiment with. As in, my wife won't let me :)

      --
      My sig sucks.
  3. Fix for glass tabletops... by MyHair · · Score: 5, Funny

    although, the glass tops on tables does make using optical mice a pain there.

    Rub some sandpaper over the part of the glass where the mouse will be. Problem solved!

    1. Re:Fix for glass tabletops... by FuzzyDaddy · · Score: 5, Funny
      Or maybe if you had some sort of special pad that went underneath your mouse...

      Oh, wait. Nevermind.

      --
      It's not wasting time, I'm educating myself.
    2. Re:Fix for glass tabletops... by Shelled · · Score: 3, Informative

      That's what I use, two spare pieces of 8 x 12 inch grey matrix arborite, glued back to back to prevent warping and the edges rounded with a router. A very thin and flat mouse pad with a fine, random pattern which makes a perfect surface for opticals. Will never wear out and cleans with Windex.

  4. Resolution by DrLudicrous · · Score: 5, Interesting
    I wonder if the resolution on these mice is at all wavelength dependent. If it were, than a blue LED would be superior to a red LED, since blue is at about 400nm and red is closer to 700nm.

    I do have to say that a blue LED mouse looks about 10X cooler than a red one. But it looks like this type of project will only interest serious modders who have some cash to spend.

    1. Re:Resolution by lirkbald · · Score: 4, Funny

      If you can move your mouse to a precision of 700nm, I'm very impressed :-)

    2. Re:Resolution by MadCow42 · · Score: 3, Interesting

      Better yet, if the mouse was sensitive to 700nm movements, I'd be impressed if he could actually USE the thing...

      Let's see... 700nm would have to equal one pixel movement, right? That means that for a full 1280-pixel travel across the screen, he'd only have to move the mouse 0.896mm (I think). That's some pretty impressive motor skills!

      MadCow.

      --
      I used to have a sig, but I set it free and it never came back.
    3. Re:Resolution by theLOUDroom · · Score: 3, Interesting

      If you can move your mouse to a precision of 700nm, I'm very impressed :-)
      I know I guy who could probably do this.
      He's a neurobiology professor.
      He says he used to be able to hold his hand steady to within one wavelength of light. I haven't seen it but, I bet it would be pretty impressive to watch. Of couse, without a nice microscope, you might as well not watch at all :)

      --
      Life is too short to proofread.
    4. Re:Resolution by Anonymous+Custard · · Score: 4, Insightful

      Let's see... 700nm would have to equal one pixel movement, right? That means that for a full 1280-pixel travel across the screen, he'd only have to move the mouse 0.896mm (I think).

      (Disclaimer: fuzzy math ahead)

      Who says the mouse hardware has to send a constant (not variable) motion:pixel signal? Lets assume it sends a 'move cursor' command once per millisecond. I (just now!) moved my mouse across my 1024 pixel screen, and it took about two inches (5 centimeters) of mouse movement, at default windows mouse settings. That's about 2.054 pixels per millimeter mouse movement. During each millisecond, a move of anywhere from 700nm-1cm could translate to a one pixel cursor movement, then 1.00000001cm - 2cm would be two pixels, etc. The sharpness would only come into play if someone managed to move it 701nm in less than one millisecond, it would still correspond to a one pixel movement, where as less accurate mice would not move the mouse at all.

      I don't think it matters whether your beam is 400nm or 700nm, unless it helps the laser track the mouse across non-optimal surfaces such as solid colors or glass. What may appear solid to a sensor at 700nm resolution could appear slightly patterned at 400nm, kind of like doubling magnification on a microscope allows you to find texture on surfaces which previously seemed flat.

  5. Black light by hero · · Score: 4, Interesting

    How about black light on a white mouse pad? That would be pretty nifty.

    -hero.

  6. Red/White/Blue... by monadicIO · · Score: 5, Funny

    Cool! I myself wanted to write a long FAQ about how to do an analogous thing for traditional mice. i.e. how to use a whiteboard marker to change the ball to match your decor.....but got bogged down by technical details...perhaps someone can help me...

    --

    The law of excluded middle : Either I'm foo or I'm foobar

  7. Which color works best? by Blimey85 · · Score: 3, Interesting
    Back when optical mice were still on the drawing board, was any testing done to determine which color offered the best performance or was red simply chosen because the creator(s) thought it looked cool?

    Personally I would rather have blue to match the blue case on my computer but the mouse that I have isn't all that responsive as it is and if it gets any worse, it wouldn't be usable.

    Maybe one of the mod sites could do a test to see which colors offer the best performance and which colors should be avoided.

    --
    How is it that one careless match can start a forest fire, but it takes a whole box to start a campfire?
    1. Re:Which color works best? by Ubergrendle · · Score: 3, Funny

      Blue was rejected due to users making a possible inference to a BSOD.

      --
      John Maynard Keynes: "When the facts change, I change my mind. What do you do?"
    2. Re:Which color works best? by Idarubicin · · Score: 5, Informative
      Please back up your studies with links.

      Please stop being lazy and Google for it yourself. The original poster is quite correct. The human eye is most sensitive to green light. Going from red (632 nm) to green (532 nm) there is an approximately fourfold increase in sensitivity. That's why green laser pointers are starting to appear, despite their cost. Novelty value, certainly, but also because a laser pointer limited to a safe power is four times more visible in green than in red.

      My guess is that it is because green does not re-transmit as far in distance as red does. Red has a longer wavelength and so can travel further without absorption. You don't want your enemy to be able to see you as well, right?

      The eye can resolve finer variations in contrast and brightness in green than in red, as well--hence the use of green displays in night vision scopes. Incidentally, it doesn't matter at all what colour your night vision scopes' display is from the enemy's point of view. Night vision devices are almost always passive devices that collect existing light. As long as they are properly fitted, they aren't directing any radiation--red, green, visible, invisible--outward, so there's nothing to see.

      There was a study done about what would be better to use for star watching: green or red.

      For amateur astronomers, red LED flashlights are available. They are used because even a fairly bright red LED is perceived as relatively dim by the eye, so your eyes don't lose their dark adaptation every time you check your star charts.

      As an aside to anyone here who works with near-IR lasers...you know that a 200 mW diode laser at 670 nm (very red) looks no brighter than a 5 mW HeNe (red, 632 nm)--indeed, it looks quite a bit dimmer after all those burn spots start occluding your vision. Wavelength matters just as much as power when talking about perceived brightness.

      --
      ~Idarubicin
  8. Not so fine by L.+VeGas · · Score: 5, Funny

    I think I'm fine with what I've got - although, the glass tops on tables does make using optical mice a pain there.

    I thought I was fine with what I had too, until I got a glass tabletop... and started working without pants. Now I just cry every time I look down.

  9. Damn you /.! by El+Camino+SS · · Score: 4, Funny


    Aw, MAN! And I was just getting caught up on all of my ridiculous case modding and converting my Geo Storm into a Geo Storm "Type R"... ...NOW I HAVE TO CHANGE THE COLOR OF MY OPTICAL MOUSE TO GET PROPS AT THE DAMN LAN PARTY.

    (Like Heston) Damn you. DAMN YOU ALL TO HELL!

    1. Re:Damn you /.! by Anonymous Coward · · Score: 4, Funny

      Geo Storm "Type R"

      You too? I got an extra sticker if you need it.

      (Like Heston) Damn you. DAMN YOU ALL TO HELL!

      Well, since he has Reagan Disease (Alzheimers), shouldn't that be more like: Damn you. Dam holds water. Sandwich ape! Gun go boom! Hello pill lady. PILL LADY IS MADE OF APES!

    2. Re:Damn you /.! by nolife · · Score: 4, Funny

      I have made some mods to my computer..
      I changed my case led's to show 133 when I actually only have a 100, a racing stripe on my burner, swiped an "Intel inside" sticker from a disply at Walmart and I hooked the 2940UW external led connector to the green power AND the yellow turbo light on the case front. Eventually I'll fire up Winbench but I figure I'm good for at least 60 more FPS in Doom..

      --
      Bad boys rape our young girls but Violet gives willingly.
  10. Cool looking, But... by CaffeineAddict2001 · · Score: 5, Interesting

    The problem is that this can seriously degrade performance.

    What I want to know is: Would it be possible to come up with a mod design in which it switches between red and blue? (Red when it's moving, Blue when it's idle)

    I noticed the light turns off when the mouse is Idle with my intellimouse, maybe this could be switched around a bit.

    1. Re:Cool looking, But... by monadicIO · · Score: 5, Funny
      Red when it's moving, Blue when it's idle)

      ..... and yellow if you should stop soon. Of course, you could just speed up insanely onto the next window before it turns red...

      --

      The law of excluded middle : Either I'm foo or I'm foobar

    2. Re:Cool looking, But... by ByteHog · · Score: 3, Interesting

      What about the Tri-color LED's? Have a certain color show for a given speed / acceleration, mouse clicks, etc... This one for example. No idea how this could be done, but it'd be damn cool.

      --
      - This isn't the sig you're looking for. Move along, move along..
  11. Article: Desoldering LEDs by MyHair · · Score: 5, Informative

    From the article: With the LED's now exposed, gently heat each side of the LED's carefully pulling on them until they are removed from the PCB. Take your time. This is actually the hardest part of the whole mod.

    This shouldn't be the hardest part of the mod. Solder-removal braiding and suction solder removers are cheaply available and highly recommended. Once you remove the solder, removing the LEDs is much easier and safer. (No flying hot solder!)

  12. Re:Don't actually do this! by EmagGeek · · Score: 5, Informative
    Red has a longer wavelength than blue.

    Blue has a shorter wavelength than red.

    The reason red LEDs are used is because they are the cheapest, as longer wavelength bandgap devices are easier to make.

    The exception to this logic is infrared, since LEDs are typically used for visual indication. Infrared LEDs are useless for this purpose so manufacturers don't make nearly as many of them...

  13. Hrmm... by vasqzr · · Score: 5, Funny


    How many Slashdot'ers does it take to change an LED?


    Answer: The ISP hosting the site is about to find out....

  14. I wouldn't suggest doing it... by delus10n0 · · Score: 5, Informative

    I did this on an older style Microsoft Intellimouse, using a light blue LED from Radio Shack. And they're not kidding about losing responsiveness. I couldn't play Counter-Strike anymore or any other games which required me to move the mouse quickly. The mouse would just lose tracking and the cursor would freeze on the screen. I swapped the original red LED back in, and what do you know, it works fine again.

    I don't recall the URL, but about a year ago someone did a comparison of about 10 different LED colors they tried in an optical mouse, and found that red is the best. (Duhh)

    --
    Not All Who Wander Are Lost
    1. Re:I wouldn't suggest doing it... by Glytch · · Score: 4, Informative

      Actually, if you'd read the article, they said that the mod would not lower responsiveness so long as you used a bright enough LED. Bright red LEDs just happen to be cheapest. That's why they're used most often in manufacturing.

  15. Red is Dead by ajs · · Score: 4, Interesting


    A great scene is a great film (and I presume a great play, but I was too young to see it at the time).

    The line is, of course, from The Wiz, which starred Diana Ross (Dorothy) Michael Jackson (Scarecrow) and Nipsey Russell (Tinman). My favorite song was "You Can't Win", which was sung by MJ. It's basically the three laws of thermodymamics, turned into a song about pessimism.

    The "Red is Dead" line comes from a scene were they first get to the Emerald City. Everyone's dancing around this huge city square that's all lit green. Everyone's actually wearing white, but because of the lighting it looks green. Then there's an announcement that green is no longer in and the new color is red. Lights change, everyone is in red, and the dance continues. A few minutes later, the announcement proclaims, "Red is Dead" and I think the color moves on to gold.

    This film was made at the hight of the disco craze, and Diana Ross was very much a part of it. I was kind of suprised to see her poking such fun at the whirling fashion trends that came and went in weeks in the late 70s.

    1. Re:Red is Dead by JUSTONEMORELATTE · · Score: 3, Insightful

      I fear you think too highly of this generation's memory
      Never attribute to cultural literacy that which can adequately be attributed to a simple rhyme.
      --

  16. Red is for mood. by grub · · Score: 5, Funny


    The faint glow of a red light while looking at pr0n just seems natural.

    --
    Trolling is a art,
  17. The reason they use red... by GoRK · · Score: 5, Insightful

    Yes, red LED's are cheaper, but there is another reason, too.. They also want to use the cheapest CCD available. That's going to be a monochrome CCD that's sensitive to larger wavelengths. A red LED is going to work better on that.

    With that in mind, an Infrared LED would probably work great with optical mice and their cheap CCD's.. maybe even better than red. You might have to remove an IR filter from in front of the CCD, and be wary of using them in a room with flourescent lighting, but it'd be good to try. How cool is an optical mouse with apparently NO light?!?!

    If you want the "cool" blue look for whatever twisted ass reason, just use a blue LED and an IR LED in paralell. You might have to play with different led's/led voltages to get the right balance between a responsive mouse and the cool blue glow your riceboy heart desires, but again, it should work.

    ~GoRK

    1. Re:The reason they use red... by BeBoxer · · Score: 4, Interesting

      Works great. I've had an IR LED one of my mouse for quite a while now. It's hooked up to my jukebox PC which is out in the den. I got tired of having the mouse randomly flashing from dim to bright and back whenever it thought that maybe something was moving underneath it. It liked to do it the most when I was trying to watch movies. Dropped in an IR LED, and it works great. No more flashing.

    2. Re:The reason they use red... by radish · · Score: 5, Funny

      How cool is an optical mouse with apparently NO light?!?!


      About as cool as a 20 year old Sun optical mouse ;)

      --

      ---- Den ene knappen er powerknapp, den andre er Bender voice knapp "Bite My Shiny Metal Ass"

    3. Re:The reason they use red... by jellomizer · · Score: 4, Funny

      Of course you need the cool mousepad with the mouse for the Old Sun Optical Mouse.
      I remembered when someone told me about the "New" Microsoft optical mouse. at the time I was working on a Sun Workstation in the computer lab, and he was talking some junk on how inovative MS is. So basicly I turned the mose over that I was working with and showed him that it didnt have a mouse ball. Then I told him that this particular mouse is about 6 years old. Luckaly that shut him up and I was able to get to work.

      --
      If something is so important that you feel the need to post it on the internet... It probably isn't that important.
    4. Re:The reason they use red... by Quixote · · Score: 3, Funny
      About as cool as a 20 year old Sun optical mouse ;)

      Oh, I have to tell this story. Some guys at work took a Sun to a trade-show. As luck would have it, they forgot to pack the mousepad that goes with one of those mice. It was a Saturday; they were in a far-away city, and none of the stores carried that pad. The demo was to start the next day, and we couldn't send them a mousepad that quickly.

      So what did they do? What all good engineers do: they improvised. They took mirror (bought at a local store) the size of the mousepad, and took some filament tape (used for packaging). They put the tape horizontally on half the mirror; vertically on the other half. To move the mouse, you would scan it on the 'horizontal' half till you got to the right row, and the 'vertical' half to get to the right column. Since the demo wasn't really _that_ mouse-intensive, it worked like a charm!

      Goes down in my book as one of the coolest hacks under crunch. I know, its off-topic, but the site is slashdotted and we need some idle conversation here.. :-)

  18. Optical mice hork down batteries by Dr.+Zowie · · Score: 3, Informative

    ... like there's no tomorrow.

    I have two Logitech wireless mice: one at work, one at home. I spend comparable amounts of time logged in both places (*sigh*). The one at home is a mechanical mouse, the one at work is an optical mouse.

    My optical mouse has been through five sets of AA batteries in the amount of time it took my mechanical mouse to finish off one set of AAAs.

    And you can't use rechargables, because these bad boys need the full 1.7 volts from those Alkaline cells -- the 1.3 from NiCd just won't cut it.

    That's just nasty.

    1. Re:Optical mice hork down batteries by kennylives · · Score: 3, Informative
      And you can't use rechargables, because these bad boys need the full 1.7 volts from those Alkaline cells -- the 1.3 from NiCd just won't cut it.

      NiCad? What is this, 1982?? Try high-output NiMH instead. I've got a couple of sets for my digicam (which will destroy a set of alkalines faster than it takes to fill a CF card), and they're great. See Steve's digicams for a rundown of what's out there.

      --

      Where the value of X-Mailer: is the true measure of a man...

  19. Re:Glass tabletop fix by LokiFoo · · Score: 5, Funny

    That is a sooo very typical White Trash solution. Good god, howtacky can you be? Hope you were just kiddin, otherwise I pity you and the trailer park from where you hail.


    Of course I was kidding, but you just gave me an idea. I can put the red LED's in the eyes of the pink flamingos out in my front yard...

  20. Computer mods... by GnomeKing · · Score: 5, Funny

    Every time I see one of these articles, this one in particular, it reminds me of the blokes who spend thousands of pounds to put UV tubes under their cars

    However, the main difference I can see between the two is that when the car modders have finished, they drive around town and OCCASIONALLY some girl stops, thinks its cool, and gets in with them, while mouse modders can only use their accomplishment to click on "sign me up" for yet another porn site

  21. Logitech Mouse by Christopher_G_Lewis · · Score: 5, Informative

    Here's a link for the same mod with a Logitech Mouse.

    www.skybusiness.com/ntanner

    I've done this, and it works fine. Note that there are two Radio shack LED's that are blue, one that outputs 2600 MCD's at 4.5 volts, the other 300 at 6 volts. I used the brighter one, and have no skipping problems at all.

    Radio Shack

  22. Re:why?? by GT_Alias · · Score: 5, Insightful
    Cuz d00d....it's 1337!!

    Serously, why do you need to ask why? Present a geek with a gadget, and he will find some pointless way to modify it, just for the sake of modifying it.

    Me? I think it'd be cool as hell to have a blue LED light under my mouse.

  23. Blue LED? Nah!! by cerebralsugar · · Score: 5, Funny

    A blue LED doesn't help me get any work done. Sure, it may look cool and impress chicks, but even cooler would be an ALL KNOWING, ALL SEEING MOUSE, that wouldn't rely on me to push it around the mouse pad to get work done. It would do all the work for me because it would be that smart. And I would fall asleep during working hours.

    It would be pretty damn good at playing quake as well, much better than me.

    If I could find a mouse like that, well heck, then it could have a blue LED. Until then though, only red for it, until it gets smarter and starts doing some damn work for a change instead of just sitting there until I push it.

    --
    Easy guys, I put my pants on one leg at a time. The difference is after I put on my pants I make gold records!
  24. Re:Optical Mouse on Glass Table? by ch-chuck · · Score: 3, Funny

    The Laser pointer cat exerciser is patented - the owners have been notified and will contact you to arrange easy payment options.

    --
    try { do() || do_not(); } catch (JediException err) { yoda(err); }
  25. Mice are kinda like lightsabers for programmers by Xpilot · · Score: 5, Funny

    Sith (evil programmers) use the red ones. Blue, green and now purple are used by the good guys :)

    --
    "Backups are for wimps. Real men upload their data to an FTP site and have everyone else mirror it." -- Linus Torvalds
    1. Re:Mice are kinda like lightsabers for programmers by Jugalator · · Score: 5, Funny

      Sith (evil programmers) use the red ones. Blue, green and now purple are used by the good guys :)

      That would at least explain the reason for the LED's used by Microsoft mice. :)

      --
      Beware: In C++, your friends can see your privates!
    2. Re:Mice are kinda like lightsabers for programmers by Joe5678 · · Score: 3, Funny

      "I see you have constructed a new mouse. Your skills are complete. Indeed you are powerfull, as the Emperor has foreseen."

  26. Does it have to be a color? by JeanBaptiste · · Score: 3, Interesting

    Wouldn't an outside-of-the-visible-spectrum light work? The red gets annoying when playing at 4:am in the dark...

  27. Bah, they're not doing it right... by Jugalator · · Score: 3, Funny

    If they're going through all the trouble of changing the LED's to blue, why not change them into a superintelligent shade of blue!

    --
    Beware: In C++, your friends can see your privates!
  28. Just use a proper optical mouse... by JaredOfEuropa · · Score: 3, Interesting

    I have a Logitech optical/wireless mouse which works on just about any surface, such as:
    - My flat, smooth, featureless desktop;
    - The crap that usually sits on that desktop: plain printed paper, smooth & shiny take out pizza menu's etc.
    - My trousers, in case the desktop is too full to move a mouse over.
    - My cats! One is extremely black and short-haired, the other a multicolor longhaired one. The mouse works reasonably well on either of them, when one of them lies down on the only clear spot on my desk.
    - Wood grain of any description.

    Get a decent brand optical mouse, it is worth the higher price.

    --
    If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...
    1. Re:Just use a proper optical mouse... by saskboy · · Score: 3, Funny

      The cats must love getting stroked by a mouse, *the wrong way*. ;-)

      I'd feel sorry for them if you are playing Unreal too.

      --
      Saskboy's blog is good. 9 out of 10 dentists agree.
    2. Re:Just use a proper optical mouse... by Oliver+Wendell+Jones · · Score: 3, Funny

      I've got a Logitech optical mouse with iFeel haptic feedback (it vibrates), I doubt the cats would like that...

      --
      A computer once beat me at chess, but it was no match for me at kick boxing -- Emo Phillips
    3. Re:Just use a proper optical mouse... by Jeremy+Erwin · · Score: 3, Funny

      I have a microsoft optical mouse. works fine on shiny/mirror surfaces, such as the data (silver) side of a CD

      Does the CD work after you've scratched it up after several hours of mousepad duty?

  29. Activation Voltage by robertchin · · Score: 3, Interesting

    I don't understand how this can just work, you may be able to swap for a yellow or green LED, but a blue LED has a much higher activation voltage, which would mean that either the red LED was being overdriven, or there's a chip in charge of changing the voltage somehow because it was designed to handle other color LEDs as well. The blue LED should be really dim if the voltage is for a red LED (GaAS).

  30. Re:why?? by Jugalator · · Score: 4, Insightful

    Still, MSI color their mother boards, including ports, etc in a purple hue. I'm pretty sure they'd get the material in that boring green color easier, but it's all about standing out of the crowd. Same reason to why you'd make your LED blue.

    --
    Beware: In C++, your friends can see your privates!
  31. One source for bright LEDs by ryanvm · · Score: 3, Informative

    Well, I've never bought LEDs from them, but I know they have a pretty good selection of VERY bright LEDs of practically any color.

    http://hosfelt.com/en-us/dept_54.html

  32. After reading this article... by Municipa · · Score: 3, Funny

    I am considering hanging myself by my cordless mouse.

  33. Another reason NOT to switch to blue by mamba-mamba · · Score: 3, Interesting

    Obviously this replacement worked for the story's author, but there is a technical point I haven't seen raised yet: Blue LED's have a much higher forward voltage drop than red LED's, and will often not turn on all the way in a circuit designed for red LED's.

    The typical red LED circuit is a resistor connected to 5 volts (sometimes 3.3) in series with the LED. The resistor limits the current that can pass through the LED. The value of the resistor is based on some typical forward voltage across the LED. That is, the 5 volts will end up being partially across the resistor, and partially across the LED. The resistor is calculated so that the typical voltage drop will yield the desired current.

    The voltage drop on a red LED is about 1 or 1.5 volts or something (I don't remember exactly) but blue LED's ca drop around 3 or 4 volts (IIRC). This throws off the calculations used in selecting a current-limiting resistor for the typical (red) LED circuit. A 3.3 volt circuit might not even turn a blue LED on at all.

    The best way to turn on a blue LED is to put it in series with a simple current source (this can just be one matched pair of transistors with a current setting resistor on one of them) or, when possible, to use 12 volts with a current-limiting resistor in series.

    Green and yellow are close enough to red that they don't pose a problem.

    MM
    --

    --
    By including this sig, the copyright holders of this work or collection unreservedly place it in the public domain.
  34. Why make, when you can buy... by protohiro1 · · Score: 3, Interesting

    I ran across this . Its a really cool mouse that has 24(!) user selectable LED colors. You change the color by hitting a switch on the mouse. Now that's cool. Next is to have a red, green and blue LED with variabe instensities...

    --
    Sig removed because it was obnoxious
  35. In other words... by andyf · · Score: 5, Funny

    In other words, this article is: Slashdot - How to Change a Lightbulb!

    --

    Photos of bits of the past hiding in the present: afiler.com
  36. Re:why?? by nmg196 · · Score: 5, Funny

    Matters not, whether you can see it.
    Red, it is.
    Feel it, you can.
    Blue, it must become.

    The force is not strong with you... Much to learn you have.

  37. Re:why?? by BigBir3d · · Score: 3, Informative

    interesting story here.

  38. Where to buy ultrabright LED's? by Chicane-UK · · Score: 3, Interesting

    I have just checked around some of the well known UK suppliers (Maplin Electronics and RS Electronics) to find these ultra bright LED's in blue, but I will be damned if I can find em.

    The very brightest I saw was 2000MCD - and that was being sold as the highest brightness at nearly $7US for a single LED.

    Suggestions on where to buy from please?

    Thanks!

    --
    "Hey! Unless this is a nude love-in, get the hell off my property!!"
    1. Re:Where to buy ultrabright LED's? by Anonymous Coward · · Score: 4, Informative

      Hello,
      Yes, the hosting company shut down the site temporarily. Crippled their server. Sorry guys...I tried to keep it up.

      About the LED's used in this mod...
      They are from superbrightleds.com (go figure huh?) hehe

      You need them that bright in order for them to work properly. Hope this helps!

  39. Re:Major Headline! by kaden · · Score: 3, Insightful

    Perhaps because that study is bad science? It ignores the fact that people with the emotional/physical problems they describe are more likely to be internet addicts than the average person. They have proven no strong, general correlation, and it is akin to saying "Piloting a 747 makes you a very smart and focused person" when really, the people who are doing that usually already have those qualities.

  40. Re:Slashdotted by RedWolves2 · · Score: 3, Interesting

    It is not the first. I saw one site last month check the site referrer and if you came from Slashdot it gave a message to "Go Away!"

  41. Blue is Cool - here's an article on why! by swordboy · · Score: 5, Interesting

    I do have to say that a blue LED mouse looks about 10X cooler than a red one.

    Here's Why

    After reading this article yesterday, I pondered changing the LED in my mouse. Has slashdot implmented some sort of psychic cookies or something?

    --

    Life is the leading cause of death in America.
  42. Night Vision by cybermace5 · · Score: 3, Funny

    The obvious reason NOT to do this.

    On submarines and ships, they used to have only red lights inside when it was dark (or the person who had to go outside would wear red goggles inside). This was to preserve the ability to see detail in the dark. The eye's light sensors are able to recover quickly from red light, less so from other wavelengths.

    Remember this at your next dimly-lit LAN party, where you've modded your computer and mouse with blue LEDs. And don't blame me when you trip and fall on the way to the fridge for another Mountain Dew. Or get fragged by someone you never saw, because your dark sensitivity was diminished after staring lovingly at your glowing blue mouse during respawn.

    --
    ...
  43. nice mod... by stevewm · · Score: 3, Interesting

    This is a cool mod to do if you have a mouse with clear sides :D (The $12 Logitech model B12 comes to mind..)

    On my Logitech B12 I desoldered the factory LED, and put in its place a cut in half CD-ROM passthrough cable plug. I then went and bought 1 of every color LED that http://www.superbrightleds.com sells. When I want to change colors I just pull the LED leads out of the plug and pop it out of its plastic holder/lens.

    I've measured the voltage being delivered to every color LED when in the mouse: Aqua (max Vf 3.6), Blue (Vf 3.5), Green (Vf 3.5) and White (Vf 3.4) all get 3.35-3.5v Red (Vf 2.2), Yellow (Vf 2.4), and Orange all get 2.3v

    All of these LEDs are rated 5000mcd and above.

    Every color tracks just like the factory Red LED. And in some cases better! The White, Blue, Aqua and Green LEDs track much better on shinny surfaces. On the same surface Red, Yellow, and Orange LEDs just make the cursor jump around.

  44. How can a site named "extrememhz.com"... by Call+Me+Black+Cloud · · Score: 4, Funny

    go down so fast? This site is shutdown temporarily due to the slashdot effect.

    I suppose "extreme" could refer to minimum.

  45. -1 Moron... by Andy+Dodd · · Score: 3, Insightful

    Um, IR is the best thing you can use.

    All IR LEDs (except for maybe some outlandish ones, but none that I know of) are near-IR. Si isn't transparent to near-IR, it's transparent to far-IR (i.e. the type of IR given off by not-obscenely-hot objects). In fact, as others pointed out, most CCDs and CMOS sensors have their sensitivity peak in the near-IR area! (Note: This is the main principle that enables Sony NightShot mode. In most camcorders and digital cameras, there is an optical element that filters out near-IR light because it will utterly kill proper color rendition - In NightShot mode, this filter is moved out of the way, allowing more light in, which happens to be at the sensor's peak. Color rendition goes down the tubes, but recording something is better than recording nothing.)

    --
    retrorocket.o not found, launch anyway?
  46. Re:woodgrain by Archfeld · · Score: 3, Insightful

    it is not the wood grain but the sealant that is most likely causing the problem. If the laser reflects, things go awry. A piece of graph paper works wonders. The double LED mice also reduce the skipping noticeably.

    --
    errr....umm...*whooosh* *whoosh* Is this thing on ?
  47. Re:why?? by Jeremy+Erwin · · Score: 5, Funny

    Hah. That's nothing. I overclocked my mouse sensor to 10x. Of course, my palm is occasionally injured by the blades of the cooling fan, but I found the extra precision is useful for negotiating a bloody mousepad...

  48. Quack by shadowj · · Score: 4, Funny
    ducktape is also very good to fix your windshield cracks

    Or for repairing a broken duck.

    Personally, I prefer using DUCT tape for most applications, including removing warts. Doesn't work all that well for taping ducts, though.

    --

    --Larry

    Never attribute to malice that which is adequately explained by incompetence

  49. Try this article by Quixote · · Score: 3, Informative

    Since the site is slashdotted, here's an alternative article on the topic. Note the date: Dec 2000!
    I guess this isn't _that_ new of a hack.