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Comment by MarkusWandel | Hacker News Reader

Power supply failure? The WS281x things can go really bright, and, in bulk, suck an awful lot of current. A 12V, 3A power supply on a strip of 100 is just about enough to drive them all to full bright white, and dazzlingly bright it is. So I'd look for a blown fuse. The fact that the firmware only drives them to 31 out of a possible maximum brightness of 255 offers a clue.

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That was my first intuition as well, seeing the brigthness limited to 0x1f. With any luck, the power supply might have a fuse, and it's just the fuse that blew up.

Anyway, if you can't salvage it, standard WS281x LED strings can be hooked up to a Raspberry Pi and you could use my open source addressable LED controller :) https://github.com/mbevand/ledthemfight It comes with built-in effects. I made it very modular so for the DIY crowd, in 2 lines of Python, you can create simple custom LED effect modules. See a demo here: https://youtu.be/qpd2rILsnM4

Good idea! I’ll get the multimeter out.

These don't appear to be WS2812. Look at the Ali link he posted. There is a pic of the wires that show four conductors on the strip: 12V, red, green, and blue. I think this is an analog RGB strip where are the lights in the strip are the same color vs. individually addressible.

https://www.aliexpress.com/item/1005005485885067.html

Anybody wanting to do anything with LED lighting owes it to themselves to look at WLED. Lots of built in effects, web gui, super cheap ESP32 (or ESP 8266!) as the controller, sound-reactive, etc etc etc. WLED is running my indoor Christmas lights right now and they look great.

The actual string I have is three wires. Data and + - it’s likely they have been swapped out for cheaper lesds now, or the picture is wrong.

There are individually addressable leds that have their ‘address’ burned into them and use a ws2812-style protocol, it could be that. There will only be one continuous data wire, which is cheaper to assemble and resistant to single LED failures.

I looked at the picture again, it does show a three wire set up.

The WS2815 (12V version) actually is a 4 wire setup. It has a "backup data wire" that allows a single failed LED unit to be bypassed.

http://www.normandled.com/upload/201808/WS2815%20LED%20Datas...

Thanks for the tip off.

I've updated the code to shift right by 3 places and so go back to a 5 bit number.

That's a neat way of limiting the power usage.

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