So I'm building a prototype of this cube LED thing.

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(Daniel Haber) #1

So I’m building a prototype of this cube LED thing. I solder on a section of 4 LEDs, test it, it works. Put on 4 more, test it, it works. Rinse and repeat. I’m down to 2 more segments and then bam, the newly added LEDs don’t turn on. This can be seen in the picture on the right vertical part.

I get my voltmeter out and start poking around and I think I figured out what happened. It looks like the voltage of the data line has gone down from .7V at the beginning to .08V at the strip that won’t turn on. I have a level shifter chip that should be supplying a 5V data signal but maybe the voltmeter doesn’t read it properly since it’s a signal line, idk. It looks like the data line drops about .08 - .1 volts as it goes through 4 LEDs on each side of the cube.

Does this sound right to you guys? I guess I have to run another data line for these last 2 sides?

edit: ws2812b LEDs btw

(Kris J) #2

“the newly added LEDs don’t turn on.”
Could be a dead led on the first position of the added not working leds. Maybe?

(Marc Miller) #3

I would un-solder those end sections and test them by themselves. If they work try re-soldering them on the end again. Maybe it was just a bad solder joint?

Double check you have the strip going the right way (Data in on DI and out to the next strip on DO. Could be simple mistake to make.)

I don’t think you can measure the data line with a digital multimeter since it’s pulsed so quickly. And there should be no problem running this few of LEDs. What type of LEDs are they btw?

(Yves BAZIN) #4

@Daniel_Haber I will as @marmil said. Unsolder the ‘bad strip’, test it appart it could maybe a bare solder or just a dead pixel.
Great construction BTW.

(Daniel Haber) #5

Thanks for the advice! It was something wrong with that last section of LEDs. I just finished building it after many hours of what felt like electrical surgery and it looks awesome. Now I just have to make it react to music haha

(Yves BAZIN) #6

@Daniel_Haber great job !!! Can’t wait te see the final build.

(Jay) #7

If you have updates on this, show us! This was something I was going to do but currently no time :frowning: