ws2812b 32x64 PSU (2048 LEDs)?

So I built this nice LED Matrix from 2048 WS2812B LEDs. After solving the RAM/ NeopixelLib problem with a teensy 3.2 I ran a test. After a while I got the "smell of Ampere" ::) (finding the problem was easy, I nearly burned my fingers touching the wires from the PSU) So the 5V part of a PC PSU could give ~200W, but the Display could draw about 600+W. To get this done in time I was thinking about using 3 PSU with all 5V wires "bundled" to avoid the heat problem. (the Display power is wired better: 5V on the top, Ground on the bottom, the LED strants in between). Or is there any other affordable PSU for such cases?

How are your leds wired in terms of power, data, and ground? All continuous or properly broken into groups?

data is one row (as usual for the WS2812b, at least when the RAM of the uc controller can handle it. The teensy 3.2 has 64k and can handle that with the Adafruit neopixel Lib).

the power ist organized this way: the LEDs are in collumns of 32 pieces. 5V is a row on the top, ground a row on the bottom, so the strants are colloumns between that and each LED has the same lenght of wire from 5V to ground.

The pwer "rails" are feed at 3 evenly distributed point of the rails. So I was thinking of feeding these 3 points from 3 single PC PSUs to lower load on eah PSU. (pics to declare that better earliest tonight, when I'm back home)

I also had similar problems, but with a bit smaller display, made of WS2818B LED strips. Strips were owerheating, and lasts LEDs were dimmed.

I would wire thicker wire to the start and end of every column/row (I'm not sure if your strips are wired in rows or in columns). Then, there will be 3 wires for 64 LEDs, making it a smaller load to them. Also, you have balanced power distribution to every LED. Yes, you will have bunch of 64 wires, but I will separate them into 4 groups, one PS for every one of them, and maybe use few wires to connect the PSs together, to have balanced power.

I did something very simmilar like you suggest (IIUC). The problem is not at the stripes nor (at the moment) at the power distribution wire. Its the wire from the PSU to the Display (the part from teh PSU you connect to the HDD normaly). So the question is more has someone done the same with woh many PSUs (and what kind of PSU)

mclien: . Its the wire from the PSU to the Display (the part from teh PSU you connect to the HDD normaly). So the question is more has someone done the same with woh many PSUs (and what kind of PSU)

If you connected it all to the wires to HDD, there are just few thick wires, not designed for huge load. I would solder fower wires from your display directly onto the PS board.

Well, what I once did, was soldering wires directly to the PS board, cutting the existing wires. And I just used what I had laying around, 3 different PS, 3 different brands, 3 different max power. Is it working? Yes? Should it be done this way? Maybe not. But it works. Try on your own risk.

mclien: data is one row (as usual for the WS2812b, at least when the RAM of the uc controller can handle it. The teensy 3.2 has 64k and can handle that with the Adafruit neopixel Lib).

the power ist organized this way: the LEDs are in collumns of 32 pieces. 5V is a row on the top, ground a row on the bottom, so the strants are colloumns between that and each LED has the same lenght of wire from 5V to ground.

The pwer "rails" are feed at 3 evenly distributed point of the rails. So I was thinking of feeding these 3 points from 3 single PC PSUs to lower load on eah PSU. (pics to declare that better earliest tonight, when I'm back home)

3 separate psus would work if you break the power lines between the groups. Maybe consider splitting data lines as well for faster response times.

But you mention computer psus, meaning you've got an unused 12v line? Some psus can be unstable on the 5v line if nothing is hooked up to the rest of it. Instead of buying additional pc psus, look into proper 5v power supplies that aren't pc specific.

problem is the 5V 200-300W power supplies aren't easy to find nor cheap. Where I have plenty of PC PSU lying around. (where the only source to get the needed 600-700W, would be 4 supplies for 100 Euro each) Would it help to put "some" load to the 12V line to make the 5V line more stable?

Or is the Adafruit hint to put a capacitor at the 5V line do the trick?

What are the wattage ratings on the psus? Maybe you can put those 12v lines to use with a little magic

Have you never try to open one of your PS and check the switching ic? I'm quite familiar with the old ones with TL494, in almost of these the 5V line has the max current avalaible. Some problem can arise if loading too much the 5V without loading the 12V, the last will increase in voltage and maybe trip the over voltage protection. Both line are involved in feedback regulation of the ic, es:

|500x250

See R 38/39/40/41. In case you are interested here you can find some schematics of PC ATX PSU.

Ciao, Ale.

Did a bit of basement diving and there they were: 12 pieces of 250W PSU, rated 120W/ 25A on the 5V line. So I think using 6 of those should do the trick. As for the load at the 12V line a friend hinted me to "just" hook up a 20W halogen bulb to that should be enough load to stabelize that line. I even thougt to solder those inside the PSU right in the path of the fan (or to play save even outsite in the path of the fan).

Only question for me is: there are 3 different 5V lines mentioned and I'm not sure to which connector each of that belong: 5V (this is the only one rated for 25A, the other are just a fraction of that) 5VSB -5V (I guess that one isn't connectable by accident) EDIT: Sorry, please hit me for not googleing first, have it now. (Solution: Basicly "any" red wire is +5V. 5VSB ist standy +5V and -5V is mostly white)

INTP: What are the wattage ratings on the psus? Maybe you can put those 12v lines to use with a little magic

I thought of that, but somehow didn't found an easy way to do that. I think I'll try the 6 PSU with 20W halogen bulb at the 12V line.

I know the trick to bridge the PIN 14(green) to ground (PIN 13/15) to switch the PSU on without mainboard. The problem here is: I'd like to leave the bridge in place, leave all PSU switched on an power all this at once by switching the over the muti-pole socket wire. Sadly these PSU only switch on, if the power is turned on first and the the bridge is put in place. Is there a trick to do that with the PIN 8 PWR_OK?

Put a 5V rele on 5Vsb to close the pwron when you switch it on.

Ciao, Ale.

ilguargua: Put a 5V rele on 5Vsb to close the pwron when you switch it on.

Is that theory or tested?

Other question: I now will use 6 PSU to run the Display and a teensy which drives it and a raspi which feeds data to the teensy via UART. So should I power the teensy and the raspi from the PSUs (if so has the raspi another power in than usb?)? or should I power the raspi and teensy from USB and only the panel from the PSUs? And should I connect ground from all power sources together or not?

Wouldn’t be much of a task to run off a 5v line into a chopped usb plug for the pi. Putting the power in the USB ports presumably keeps the voltage regulation working, since the 5v source may fluctuate considering the unconventional use.

Mind if I ask what kind of program you’re running for the data line from the pi? I’ve got a couple Pis and Pi Zeros that aren’t being used.

Not tested, but I don't see any reason why it shouldn't work. The 5Vsb is there as soon you plug in your ps, so just use a NO contact to close green wire to ground. It is of course limited in power respect the main 5V supply, but I think you can use it to supply at least the arduino, raspi sometime need more power. Since it's a totally independent line, I'll have less noise and fluctuation. And yes, you have to connect all the grounds together.

Ciao, Ale.

Thanks for all the hints so far, I guess easiest will be the PSU to USB hack from the PSU to the PI

As for the programm: Most of that is done by my son, but the main idea is: We get an animation as mp4 movie for which my son writes a python program, converting it to a sequence of RGB values (32x64 pixel each). these output will then be feed over UART (RX/TX) to a teensy, which uses the adafruit neopixel Lib to runn the pixel Display. Oh and just in case somebody suggests to use that Neo_Matrix Lib: As far as I read it, that will only work if the matrix collumns always starts at the same site (like one line, CR, next line). But since I uit that matrix from LED strants, I I simplyfied the wireing by going back and forth First line left right, next right to left and so on (up and down to be precizly)

ilguargua: Not tested, but I don't see any reason why it shouldn't work. The 5Vsb is there as soon you plug in your ps, so just use a NO contact to close green wire to ground.

something is wierd about that or I miss something obvious. I put the coil between 5VSB and ground. And to the pins that are closed with the coil activated I put green and ground. Strange thin is: I hear the colsing click, when plugging in the PSU, then nothing happens. Unplugging the PSU relusts in several click sounds. So is there a diode, cap or thomething else missing?

EDIT: it seems to my that the relais is simply too fast. So I might need a trick to delay the closing of the contact just a tiny bit (about 0.5sec max, I'd say)

mclien: So I built this nice LED Matrix from 2048 WS2812B LEDs. After solving the RAM/ NeopixelLib problem with a teensy 3.2 I ran a test. After a while I got the "smell of Ampere" ::) (finding the problem was easy, I nearly burned my fingers touching the wires from the PSU)

ROFLMAO!!!! "Smell of Ampere".

Don't blame André for all the problems. Georg was part of the problem as well.