Powering 30+ RGB LED Lights with Photon

Hi All,

I have an idea for a project that requires controlling a little over 30 of these RGB LEDs

I want to control them individually and have most of them will be off the majority of the time. Occasionally I want to be able to turn them on as a solid light or flashing. I would be happy just using solid R, G, and B, but if there is a way to expand into a whole mix of colors with them I am not opposed.

I would like to use a Photon, since I already have one lying around and would like the project to take advantage of its wifi capabilities. I have done a bit of research in using a shift register as an LED driver IC, but wanted to talk it over with some more experienced folks since there is likely a better way out there for me to learn that I don’t know of yet. I am just worried I’ll quickly get in over my head with 30+ MOSFETs coming out of unnecessary shift registrars when there is a more elegant solution I don’t know of.

Thanks ahead of time for any help.

I think you should look at addressable LEDs like this or this or this. There are many configurations available and each can be controlled separately.

they are typically very easy to power, control, and there are ready-to-roll libraries that support that hardware

Thanks bulldog! I’ve actually worked with addressable LED strips before, but I don’t think they’d be helpful for what I’m looking to do.

My fault for not being more clear. The project would have the LEDs protruding from different points on a globe, so being able to position them individually is important. As far as I’ve seen all the addressable configurations come in preset shapes/strips. So you know of any the would allow placement of individual LEDs?

strings like these have wires in between, they also sell just the LEDs and you can wire them up yourself.

Awesome I hadn’t seen those before and missed it in your earlier comment. Thanks for the help!

Or get a strip and cut them to individual LED’s so they’re much easier to solder, as opposed to the SMD parts :slight_smile:
@wgbartley Has some lovely experience with the former if I remember my first Maker Faire correctly :innocent:

The ones I used in the word clock for that Maker Faire looked like the picture below. There were 130 of them, and it was a nightmare to cut, strip, and solder 3 wires running to each LED. I had the pads on a fair number of them rip off as well.

There are also similar LEDs that look like traditional RGB LEDs but are individually addressable. You can do a search for “P9823” to find those. However, I have not had much luck getting them to work with a Photon – they’re incredibly flickery, even when using level shifters. I’ve had better luck with a 5v Arduino, but it’s only “better” and not “perfect”.

My recommendation would be to search for “WS2811 string” (eBay, Ali, etc) and run with those if the spacing/wire length between LEDs works for your application. If not, it may be easier to splice the wires in those strings to extend them instead of working with the individually solderable LEDs.

1 Like

That looks like a nightmare to have done for 130 of them… how’d clock turn out in the end?

And I agree I think the WS211 string is the way to go.

Curious though about the P9823, why do you think the flickering is more of an issue with the Photon? Were the LEDs powered by the Photon or did you use an external power supply for the 5v?

Absolutely glorious :innocent:

1 Like

you will definitely need to power the LEDs using some other source than the Photon.

If you are clever enough you can could lite each country on the globe using one string of LEDs, bearing in mind that you may wish to waste one or two inside the globe in the case of long stretches.

You can even fade one or several, like on the word clock I did which I borrowed from @wgbartley’s project. That was created using a single string of WS2811’s.

Good luck with the project, is this some kind of Olympic medal globe?

That depends on how many LEDs you plan to have on at a given time at what color/brighntess.
As a rule of thumb you can take 20mA per subLED at full brighntess for “standard” NeoPixels, so one 100% white RGB NeoPixel will suck 60mA, so you need to do the planning for your use case.

But agreed, having a beefy power supply capable to power the Photon and all your LEDs at 100% white is the safest bet and most likely was used on the Word Clock (maybe not for 100% white tho’).

I’m not 100% sure. Maybe they’re more sensitive to signal noise or timing or something. I’ve used big caps, small caps, level shifters, resistors, etc, but nothing seems to fix it for the Photon. As for the power supply, I have a beefy 5v 8A power supply that can light up a fair amount of LEDs and power the Photon as well!

That 5v 8A supply will do 100% white, though my retinas can’t handle it!

1 Like

Interesting. And yeah I already have a few 5v power supplies from previous LED projects, just wondering since I have seen some people power them straight from a microcontroller when they have only one strand (which surprised me).

As for the project, it is actually a going to be the locations of all major space launch sites. Whenever a launch is going to happen, say within an hour or so, the LED at that location will start pulsing. Then at liftoff it’ll change colors or turn solid, or something (haven’t decided yet). Will also do different colors for held launches or scrubbed launches.

2 Likes

That’s amazing! Please share when you’ve completed it!

You could also design your own power supply using 24 Volt DC To 5 Volt DC and Using transistors and shift registers create a pretty awesome light show