I currently have a display cabinet that uses some RGB LED strips for lighting. Some of the old LEDs are starting to fail, and I also wanted a bit of additional light output, so its time for an upgrade. As the current LEDs are primarily used to simulate a warm white lighting, I thought I'd replace the existing RGB strip with some RGBW strip that has warm white LEDs in addition to the regular RGB LEDs.
So, I ordered some from a local (UK) supplier on eBay, along with the Shelly RGBW2 controller and some connectors, patch leads etc. I re-flashed the Shelly controller with my own firmware, and proceeded to do some testing - which is when things started to go wrong.
The blue and warm white LEDs were working as expected, but the red and green channels were inverted. Of course, the first thing I suspected was that I'd made a simple mistake in my new firmware, and accidentally swapped my red and green GPIO pins. After an hour or so of head scratching and getting nowhere, I was at the stage of checking the physical connections to the LED strip, and using a meter to check that the red and green coloured wires feeding the LED strip were actually connected to the pads along the strip that are labelled R and G, and it all checked-out.
Eventually I powered-up my bench power supply, set it to 12v and injected power directly into the pads on the LED strip. Sure enough, the red and green LEDs have somehow been transposed!
I don't know if this is a manufacturing issue where the LEDs have placed on the strip in the wrong orientation, or whether it's simply a case of the person who designed the circuit being red/green colour-blind 🙂
I'd ordered three of these 5 metre long strips, and they all have the same problem. As it's easy enough to fix, either by changing my custom firmware to transpose the red and green channels or by swapping them over in the wiring between the controller and the strips, I've decided to keep the LED strips. I have messaged the eBay seller to alert them to the problem though, but haven't heard back yet.
In hindsight, I guess I should have been suspicious of the eBay listing anyway, as it shows an RGB strip displaying different colours for each LED, which isn't possible unless you use a much more expensive strip with individually addressable LEDs, and that's not what was being advertised in the listing.
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