Hi, i am thinking in make led tubes with ws2813 led strips
Every tube have an input and output
Connected like that photo:
The first problem is that the ws2813 led strips if two LEDs burns consecutive, the rest of the LED strip after the two consecutive burned LEDs stop working , i lost all the tubes if this happen.
(I cant Weld leds or change the tube, because its in the ceiling)
Leaving the whole setup like this:
I can do this?
In this photo what I do is that the data pin of the LEDs is directly connected to the Arduino and does not pass through the rest of the LED strips of the other tubes, so that if two consecutive LEDs are burned, only said tube turns off and the rest will continue to work, is it possible to do this? but every tube needs to work independent(with other colors)
I have another problem and that is that each tube has 40 LEDs and the glediator protocol says that it supports only 512 LEDs, which would be about 12 tubes:
With arduino mega, can I control more LEDs or should I use some protocol like dmx?
First of all, it rarely happens that 2 or even 1 led burns, particularly if they are in a (semi) permanent structure. What tends to break them is installing and moving around, but you should always keep your structure serviceable. That means you should be able to remove a whole tube easily, so you should have 3 pin plugs in between them (ideally IP67)
No, quite simply put, but what you can do is connect the 'Din' of every tube to a separate pin on the Arduino.
The signal received by the first led, which takes it's relevant data and forwards the rest to the next led, so the position within the chain is what defines it's address.
The limitation for controlling LEDs is firstly memory, so on an UNO 512 would anyway be fairly close to the maximum. I have no idea about 'Glediator' though.
DMX is not going to solve your issue, let's be clear about that.
You can use any Arduinmo library for addressing neopixel LED you like, but you will have to create your own patterns, and if you want to have all output buffers in memory all the time, and it is far easier to program it that way, a Mega would be the appropriate choice. Mind you is you intend to use this sort of structure in a club with a VJ, one would use different software all together and you would want as few input pins as possible.
In that case you should get yourself an Artnet node with LED-strip output. DMX is 512 channels per universe, that comes down to 170 LEDs. Of course you can do separate universes for parts of the setup, and have individual DMX to SPI converters, for which you can use Arduinos, but in my opinion that is taking the long way home.
In that case you put plugs between the tubes, test the tubes before you hang them, and rarely will they break 2 of them in the same weekend.
But it happens of course, though rarely during the evening in my experience. Usually during build up and testing, and then you have a lot of stress getting it all to work before you open.
Best practice is to have a few spare tubes.
Of course you will have to power the whole thing, and that is going to be a significant part of the challenge. Ground loops are lurking.
Covering distance with the 800KHz signal is another challenge you will face.
You can but it supports only up to 1024 LEDs, and not really what i meant. This supports up to 5440, though at that amount the refresh rate is a tad low.
What i mean is that the data signal that controls WS281x chips, which is 5v Logic (regardless of the VCC of the led chip) at 800KHz, is rater sensitive to Capacitance of the cable. Covering 10 meters from it's initial point of generation, through a thin wire, may work, but that is near the crossover point depending on the capacitance of the cable. (thicker cables have more capacitance which is worse)
Between LEDs is this is more or less similar.
This is a different matter, it uses RS485 protocol at 250Kbps, and is rated to be stable for up to 100 meters. This includes all possible plugs (DMX allows daisy-chaining) and uses shielded twisted-pair cable.
When using a Cat-5 UTP cable, you can probably get up to 300 meters if you put a 120R terminator at the end.
But as i said before, DMX has 512 individual channels, that means you can independently control a maximum of 170 LEDs per universe, which then still need to be decode (Unless you use DMX LEDs, but not only are they expensive, but limited in the amount you can use per chain.)
'We' (I have been involved in Deco for parties for 20 years) actually normally just use WS2811's simply because they are so cheap. If you would want higher resolution WS2812(B) would be fine, but they run at 5v which is an extra complication. For us it is RGB all the way and not RGBW. The white from RGB is fine for what it is meant to do in a club. For true white light other types of lights are normally used. (sometimes LED's but rarely strip to flood a dancefloor)
12v is preferred for power, simply because voltage-drop is absolute.
A ws2811 Strip still works fine if the voltage has dropped from 12v to even as low as 10v, before you will see discolouring. If you lose 2v from 5v you only have 3v left and usually not even the decoding works at that level.
For data transmission, thinner cables are better, for power thicker cables are better.
I have not have 20 years with WS2811, only about 7. I don't think they have been around for that long. And yes i have seen many burnt ones of course. Mainly they deal very poorly with 12v on the data line. They burned ones that i have encountered were either the first, or the last of a strip. Of course there have been other malfunctions which were mostly related to capacitance of the data cable, but once we understood why this was happening and how to counteract that, those have been resolved. Other issues have been 'Ground Loops' and poor soldering causing bad connections or breaking of connections usually after transport.
All in all, they rarely (and i mean actually not that i remember) break during the night.
If you are using software that has Artnet output, direct generation of SPI signal is the way to go, and will leave the dmx for fixtures that require that as a control signal.