deskthority

Hey guys,

I need some advice

I want to change the colour of the (Num- Scrol- Caps-lock) LEDs in the G80s of my co-worker and me.
Does anyone know what LEDs (and possibly resistors) I'd need and were I could order some?
Looking for the following Colours: Blue and Red (maybe Pink if available)
The Blue LEDs should not be brighter than the standard Greens LEDs, the Red ones might be brighter, though.

Thanks in advance.

Greetings

Shouldn't be too hard. You need a soldering iron to do it properly, though.
1)Open the keyboard and have a look at what formfactor of LEDs is required. Probably 5mm through hole LEDs in older boards but that could be different in modern ones.
2) Head to an electronics shop (e.g. pollin.de, reichelt.de, conrad.de, voelkner.de in Germany) and order a set of resistors (5-10 EUR) and a bunch of LEDs (~0.10 EUR each). Avoid ultrabright ones.
3) Try different combinations. For convenient experimentation you could also order a cheap breadboard.

Easiest is to get the old style ones with color lens just like what is in there now. These are really white led with the correct 3.3 operating voltage, so no need to deal with resistor.

afaik you need 3mm ones.

and as lysol said, try and get the ones with a colored housing, not the ones which are clear.

edit: sorry, I just opened one of my 3000s to make sure and discovered that they use 5mm LEDs

Sure, coloured lenses will look best. But they are NOT a white led on the inside!! Even white LEDs aren't white on the inside - they're UV

Various factors mean that trial and error is the easiest way - as Kurrk said, get a variety box of resistors and try some out

Soarer wrote:Sure, coloured lenses will look best. But they are NOT a white led on the inside!! Even white LEDs aren't white on the inside - they're UV

Various factors mean that trial and error is the easiest way - as Kurrk said, get a variety box of resistors and try some out

Yes, LEDs in a way nearly directly "convert" electrons into photons. Because of this LEDs only emit monochromatic light. One rather exact wavelength, which is directly connected to the operating voltage. (Which is the reason why you have to use PWM to dim LEDs. They need a specific voltage to emit light.) Because of this different colors will need different voltages. The amperage does vary as well, depending of the intensity of the light the LED emits (the number of photons).

RC-1140 wrote:...
One rather exact wavelength, which is directly connected to the operating voltage. (Which is the reason why you have to use PWM to dim LEDs. They need a specific voltage to emit light.) Because of this different colors will need different voltages. The amperage does vary as well, depending of the intensity of the light the LED emits (the number of photons).

Sort of... when driving them through a resistor from a voltage that's higher than the forward voltage (Vf) of the LED, the voltage is determined by the LED. The resistor can be varied, which changes the current through the LED, which changes the brightness (it will also vary the Vf slightly, since the stated Vf is only correct at the rated current). PWM is just the easiest way to dim LEDs - you could instead use a variable resistor, a variable current source, or vary the voltage applied to a resistor + LED combination (in effect a very basic current source, with non-linear variability).

Yeah, but the problem with this is that the voltage range in which LEDs emit light is very limited.

LEDs emit light following E=h*(c/λ), and the absorbed energy depends on the material of the LED. If the energy of the electrons is too low, there's no light.

That's not a problem, since the current can be varied over a very wide range, while keeping the voltage across the LED within operating range.

You guys... why you have to get so technical all the time? Sure, all I meant was that if you took 'same' led with uncolored and colored lens the uncolored one appear 'white'.
There are also clear lens that have an operational range like those used on variable brightness backlight boards, so you don't need resistor either, but they seem to be a bit more work to locate and cost more usually. The color lens ones have the correct power requirement and no extra component or trial and error is needed. Especially on something like G80 where you can't see them directly the nicer looking clear lens isn't really needed at all. No need to make things more complex.

lysol wrote:You guys... why you have to get so technical all the time? Sure, all I meant was that if you took 'same' led with uncolored and colored lens the uncolored one appear 'white'.
There are also clear lens that have an operational range like those used on variable brightness backlight boards, so you don't need resistor either, but they seem to be a bit more work to locate and cost more usually. The color lens ones have the correct power requirement and no extra component or trial and error is needed. Especially on something like G80 where you can't see them directly the nicer looking clear lens isn't really needed at all. No need to make things more complex.

Why? Because you also incorrectly said that the voltage would be 3.3V...

lysol wrote:These are really white led with the correct 3.3 operating voltage, so no need to deal with resistor.

How incorrectly? That is generally standard 3.3v for led in pc products. I never had issues with using 3.3v led when changing color in variety of thing from keyboards, disk drives, power indicators, etc.

It varies with the technology used in the LED. You need to check the specs. Sure, swapping just LEDs will work, but it will be different brightness if the Vf is different.

Sure, there is some exception but G80 is not one of them it have 3.3v. Which again why I like the color lens ones, they are easy to find in any color in 3.3v 20-25mA which is good for what is needed. No need to worry about if red/orange/yellow is 1.8v which is more typical on clear lens type.

No, the exception is to find LEDs of differing colours that have the same Vf; typically reds will have a much lower Vf. That's regardless of whether the lens is red or clear (although it's true that clear is more common on ultra-bright types, where the loss of brightness would be a problem, and that they use different materials).

Of course you can still go looking for ones with the right Vf, but IMO it's better to choose on other parameteres (brightness, exact colour, etc) and then change the resistor.

Ok I have got a slight problem here...
The newer type don't have usual round LEDs.
I have my G80 at work so I could not check earlier.

Looks like these are SMD LEDs?

I can't take a pic of the underside. Have no tools here...

Definitely SMD. These are a bitch to solder, but not impossible.

Eh, haven't seen one like this yet. I guess it was about time they made smaller controller pcb isntead of one half the size of the switch pcb... though not sure why they didn't just make switch pcb revision to include that as it could clearly fit if the extended the pcb a little. Seems kind of dumb.