I work a lot with neopixels and LEDs, but this case is a bit special.
I'm trying to understand what is the best way to do what I need.
This post is mainly theory as I didn't wired anything yet.
So here is the background:
I'm working on a large art installation, and I need to control 54 LED strips, 2m each, so 6480 LEDs.
BUT! I only need to display one color for each strip, so 54 colors at a time.
(we don't really care for now about the number of power supplies I need...)
I need each strip to be considered as a unique long pixel.
So, instead of running a massive chained strip of 6480 adressable pixels like neopixels
(much more that an arduino could handle),
I'm trying to find a way to consider each strip as a single long pixel,
and to control it like I usually control one strip of neopixel.
For now my plan is to use SMD5050 LED strips,
and adding a driver at the beginning of each strip.
But I have no idea if such a driver exists...
I'm looking for something that could act like the WS2811 driver in the neopixel,
to be capable of setting the color of a whole strip.
The best would also be to be able to use the fastLED or neopixel libraries for these 54 "long pixels"
Is something like that is actually possible?
I can guess that the WS2811 is not powerful enough for a whole strip, or is it?
The other option I'm looking at is to use 11 TLC5940 multiplexers.
This will allow me to have enough pwm channels to drive the 54 x 3 (rgb) required pwm.
Again, does that sound possible? Is chaining 11 TLC5940 multiplexers feasible?
Sorry, this is a lot of question!
Thanks in advance for any tips on this
Hi
I'm not sure that this answer will help. FastLED can control several strips at a time, see here. The last example is interesting in your case as you can easily control all the strips with a for loop.
If you need 54 digital pins, the Arduino Mega must be the candidate.
I can guess that the WS2811 is not powerful enough for a whole strip, or is it?
It is, in fact it is a odd question. There is no limit to the length of a strip, with the WS2811 you control three LEDs at a time and they are chained.
There are lots of solutions, maybe the best would be to multiplex the drive to the strip. In effect having one pin driving and switching it to each strip in turn. You could do this quicker than the eye could see so it would look like all the strips were changing at the same time. That way you need only enough memory for one strip in the Arduino.
Maybe something or this? It's a small board containing a ws2801 chip, plus 3 MOSFETs for driving up to 5A per channel. It even has a regulator so the whole board can be powered from 12V.
lesept:
FastLED can control several strips at a time
Good to know, I didn't knew about this feature in FastLed. Might com handy!
Grumpy_Mike:
maybe the best would be to multiplex the drive to the strip. In effect having one pin driving and switching it to each strip in turn. You could do this quicker than the eye could see so it would look like all the strips were changing at the same time.
I've seen solutions like this, this is clever. My goal was to use cheaper analog strips, that why I wanted to find a way to drive 1 strip with only one ws2801 to get the best of both world. But yes, I guess multiplex is a good solution for this
Maybe something or this? It's a small board containing a ws2801 chip, plus 3 MOSFETs for driving up to 5A per channel. It even has a regulator so the whole board can be powered from 12V.
Nice! This is exactly what I had in mind but I didn't found these ones. Seems perfect. If it works a intended, it will let me drive each analog strip as a single pixel in FastLed! I have to try these as this might be the easiest way to do it.
Again, thanks you all three for these ideas, I was really curious to find a way to build huge setups. I'm still making my homeworks to learns the limits and possibilities, but your solutuions are clever
that why I wanted to find a way to drive 1 strip with only one ws2801 to get the best of both world.
Sadly that is not going to work as the ws2801 has a constant current output so is only suitable for driving LEDs in series. And that with a maximum voltage requirement of 7V.
