Hi All! I’m getting down to the nitty gritty on a large LED project, and would be so grateful if I could get the critical eye of more experienced LED folk before I roll up the sleeves on wiring.
The basics: 34x34 matrix, with 3 outstanding questions:
Do I need to account for data lag via serpentine dataline by using multiple segments?
Do I need larger wire for my wires leaving the power supply?
I’m not sure what type/power fuses to use on my power lines.
Attached is my schematic with specifics. Apologies for it being atypical; just whipped it up in Illustrator. I don’t think I’ve left out any critical info but please let me know if so! Edit: turns out I left out the Pixelblaze, ha, was planning to have it off of one of the sets of power supply lines. Diagram edited.
Not so much data lag, but if you have effectively a single long strip the data rate limitations of WS2812 will cap your frame rate. Splitting it up into a few segments and using an output expander can help.
WS2812 data rate is limited to 800kbps, or at 24 bit RGB color around 33k pixels a sec. 33k / 1156 = 28 FPS.
For fuses, you’d want to be sure that the fuse is rated for enough amperage to cover each of your power zones. But, you also want to balance it so that if there is a short, the fuse will do its job and blow and not just turn the wire/strip into a giant melty heater element. That probably means more, smaller zones. A 25A/30A fuse, large enough to cover a 1/3rd size zone, may not blow if there was a short at the far end of your display.
Disconnect the positive power side between zones, so that if a fuse does blow, the zone isn’t being powered from another zone.
There are many types of fuses, cylindrical and automotive blade fuses are pretty easy to get and both work fine with these low voltages.
You can find cylindrical fuses in my shop here:
And the Pro Output Expander boards have 4 fuse protected outputs built in, (15A per board):
Thank you SO much, @wizard . I just put in an order for another Pixelblaze and sensor board over the weekend, but will get in an order for the output expander tonight. Thanks again for your assistance.
@wizard I’ve wired the project into 4 segments of 9 strips each. Regarding the output expander’s max power distribution of 15A—my original thought was to have power, ground and data coming out of each expander’s 4 terminals to the 4 strip segments. But that would draw well over 15A at times. Seems like I can avoid that threshold issue If I power strip segments directly from power supply, and then have ground and data going from output expander to my segments (as referenced here). Then I’ll put fuses on the power lines from the power supply. Does this setup look good to you? Thanks Wizard!
Thanks again for your help along the way.