RGB light brightness


I found that the RGB light that flashes is too just too bright.

Could I make a suggestion that in the next firmware it’s set to half the brightness, or make it a setting somehow?




Thanks @jamjardavies - good feedback! We’re working on a method to control the RGB LED, will be released in the next week or two. Hopefully that helps!


+1. It seems like it should be possible to give over control of the RGB LED to the user once the core is connected and running user code. In much the same way it’s used by the core’s firmware it could be a simple way for the running code to communicate.

We’ve got a feature branch where we’re working on this now:



Hi Guys,

I noticed this feature branch was merged and provides user control over the RGB led, but does not give control over the RGB led intensity. I’ve pushed two pull requests, spark/core-firmware#57 and spark/core-common-lib#2 which give control over intensity. The default is set at 1/4 of peak intensity.

I don’t know about you guys - maybe I’m more sensitive to the light than others - but I put a dark tinted static bag over the core and still feel a little breathing cyan hole being burned in my retina at anything over 50% intensity.

Or you have kids and most of your hacking is done after it’s dark and they’re in bed! That cyan pierces my retina when all the lights in the house are dim or off.

The upside about the brightness is that even though the Core is sitting 2 rooms away, I can still see the glow from where I sit with my laptop.

Yeah it’s insanely bright! It shines through 3 mm of hard plastic in one of my projects. But the new RGB.xxx methods should solve the problem for me, so all good :smile:

@mattande Thanks for the pull request! We haven’t had a chance to review it over the holidays but we will when we get back to the office in the new year :slight_smile:

Can’t wait to dim that led! Sorry to be somewhat negative in my first post but this ‘problem’ looks like a case of being too close to the design. Sort of like those OSD banners on monitors when first turned on. Only the developer and his mom wants to see that all the time.

Just fired one of my cores up for the first time. Looking forward to seeing it in action.

If you add the following to the top of void setup, it will help quite dramatically.

RGB.color(50, 0, 0);

Generally, blue LEDs are quite a bit brighter than other colors and are the absolute worst for your night vision. I know turning it solid red isn’t dimming the default pattern, but at least it’s:

A) Not being all blinky and distracting.

B) The best color for vision at night.


C) A lot dimmer than the default!


Thanks! That does make a big difference.

btw: i can’t find the RGB Interface in the API doc.

@Coffee We haven’t added it to the docs yet, but we mention it in our latest blog post:


@Coffee now in our docs:


I just saw that the merge happened in master. How would I go to make this feature available in my spark core? Can I do it somehow without connecting it by cable?

I’m wondering how long it would take for it to accept the feature in the Sparkulator.

@zach @zachary I was going to write updated documentation for RGB.brightness() but when I checkout spark/docs it doesn’t have any of the libraries/RGB section in there already. Is the public repository up to date?

Hmm… Looks like they added that change directly to the ‘gh-pages’ branch, and not to master… I’ll see if I can check with those guys to merge those changes back into master, but in the meantime is this the commit you were looking for?


Yep looks like the changes were on gh-pages and not master, but I just merged them back into master

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I was looking for this! Tankss!

thanks for this the default flashing was keeping me awake at night.