Any info on Apple Status LED's?

[MrCheeto]

I have a Polycarb MacBook and I've gotten used to the tiny status LED lighting my keyboard and mouse. It's a very comfortable and subtle light. Since I edit photos in the dark, I appreciate that it is only light enough to indicate where my keys are and neutral enough that it doesn't effect my color perception.

Now that I'm rearranging my work area, I need to replicate this same light.

So far, searching for LED's always leads to the BRIGHTEST most WOW AMAZING blow-you-away Wish.com trite and trying to find anything remotely non retina-singing has been a dead-end endeavor. It's a "brightness war" for sure.

What information does the knowledge base have on the lights Apple uses? PWM? How do they achieve the "whiteness"? Is it a "white" LED? Does somebody offer a replacement diode for any Mac that I may be able to yoink and use as a desktop lamp independently? I'm impressed at just how pure all of the old status lights are on Macs and it sets a good benchmark for exactly what I'd like to utilize in my setup.

 

[chown33]

I think you're asking about an LED in this model of MacBook:

MacBook (2006–2012) - Wikipedia

en.wikipedia.org

That would make it an Early Intel Mac, so I moved the thread there.

If you're asking about something else, like a discrete LED or LED-based lamp, possibly USB powered, then I can move the thread again.

 

[MrCheeto]

Dunno where to put this, either. I'm looking for sources for a lamp for my desktop and the closest approximation to what I'm looking for is whatever LED's Apple have been using from the Quicksilver to today.

 

[chown33]

Let's leave it here and see what happens. That MacBook is old enough that someone might have a source for replacement parts.

If nothing else turns up, I could probably design a circuit using a random USB phone charger, an LED, and a trimpot. The charger could probably be obtained from a thrift store, such as Goodwill. The LED and trimpot could be bought from Digikey. Building it would also need a soldering iron, but you could probably borrow that.

 

[MrCheeto]

This is pretty much what I'm resigned to do but the Apple LED is peculiar in just how white and soft it is, so any details to emulate the look are appreciated. Not sure if that info is shared in the super fandom.

My plan is as such;

Since my keyboard is on a roll-out shelf, there is a desktop above the keyboard. I want to affix a lamp, say a single low-intensity LED, to the bottom of the desktop so that it illuminates (faintly) my keys. Just to give a clue how faintly: when I look down at my keyboard after staring at the screen, my eyes adjust after about ten seconds and I can see the grey lettering on my white Apple keyboard. The LED is just there to add enough light that I can perceive my keys faster. Having my MacBook on the desk was pretty good at this though I'd consider the idle state of the LED just a little brighter than I would really want if it is directly above my keys.

In the end, I figure I just run a simple + and - voltage wire via USB (from the USB port on my Apple Keyboard) to an SMD which may or may not be diffused somehow. I'd need to figure if it's OK to just run a resistor to control the brightness with voltage or do I have to go along with the whole PWM mess...or is there such thing as a purpose-made "task light" that is already trimmed to be extremely dim despite the voltage you throw in?

In the past, finding dim LED's was almost the default. They were always red and they were always dim and focused very narrowly because of the lensing body. Now it is hard to find an 0402 that isn't known in the state of California to cause melanoma and retinal injury.

Am I alone in my need to maintain night vision in a low-light work environment? I had an initial feeling that perhaps this was common and I just haven't decoded the patois.

 

[chown33]

I don't see why you'd need to resort to PWM. Any LED that can go to a low enough level with PWM would have an equivalent DC current level that would produce the same illumination. A resistor might well be several K-ohms, because LED efficiency these days is such that only a fraction of a mA might be needed to get the desired low level.

You might look into some strip-mounted warm white LEDs. These are typically designed for 12V supply, and many incorporate the current-limiting series resistor.

A search on Amazon brings up:

Amazon.com: Warm White Led Strip Light

Amazon.com: warm white led strip light

www.amazon.com

There are also color-tunable versions of these lights, and dimmable versions.
Search terms: dimmable strip lights

The main downside to strip-lights is that a package probably has about 20 times more LEDs than you'd need. The typical smallest unit is probably 3 to 5 LEDs, because that's about how many would be wired in series. That unit is then repeated down the strip, so when you cut the strip to length, it must contain an integral number of units.

If a strip is designed for full brightness at 12VDC, then it probably won't work at all at 5V. LEDs need a minimum voltage to turn on at all, and 3-5 in series probably needs at least 8-10V (though it would be worthwhile trying it at 5V).

An adjustable series resistor would probably work, but the power dissipation would need to be taken into account, so a more complex circuit with an adjustable voltage regulator might be easier to manage. It would take 12V in and have a manual control to adjust the output voltage.

Then again, you might find a perfectly suitable dimmer control for strip LEDs. I don't know what's available for something like that, or what it might cost. If you can solder, then a voltage regulator with a pot and a few caps is almost certainly under $10.


And now I can see that this really doesn't have anything to do with Early Intel Macs, so I'll move it back to the Community forum.

 

[chown33]

If you want to throw an excess of technology at the problem, a Raspberry Pi can output PWM.
Search terms: raspberry pi pwm code

A Pi can also read inputs, like up/down pushbuttons, or a rotary shaft encoder, etc. It can also accept network packets (man nc), or run a web server with a CGI backend.

The low-voltage PWM output can control a power NPN transistor to modulate a 12VDC supply.

Another project for a rainy day.