I am planning to update my few existing lighting projects with COB LED Strips. I need minimum
16.4ft (5m) strip length. Of course I can stich together few shorter strips. Ideally I am looking for
24V but single LED per pixel strip. Does it actually exist (most likely no)? All 24V strips what I found
is a 6 LEDs per pixel. 12V single LED per pixel strip also will work. And of course, strip must be
compatible with PixelBlaze.
Amazon is highly preferable as a source. (I am not buying anything on Ali Express.)
Could you please recommend one?
I agree this would be a desirable config, but I haven’t seen anything Iike this.
Did you find a 24V COB strip at any length (other than fixed white color)? I’ve only seen 12-24V strips in 5050 sized chips, groups of 6 like you mentioned.
The density of the addressable COBs I bought a while back was something like 300/m, and it was the standard/slower 800 Khz protocol, so I bet frame rates and signal integrity are challenging at 5m of the stuff.
I ordered this 24V addressable COB strip:
https://www.amazon.com/dp/B0C377LPFJ?psc=1&ref=ppx_yo2ov_dt_b_product_details
It is only 100 pixels per 5M (16.4ft), each pixel is 5sm lenth. This will be a replacement for the current SK6812 RGBW 300pixels/16.4ft strip which is used for the kitchen under cabinet lighting. Effective number of pixels is only 100 because I am re-mapping 300 RGBW LEDs into 400 RGB LEDs (I need more warm white brightness but naturally Pixelblaze does not allowed to light up all 4 LEDs in a single pixel). So, this 24 COB replacement will give me the same 100 pixels but with much better LED’s density. In a color mode this strip is a status indicator for which high power appliance is turned ON.
And for the sinlge LED per pixel I ordered this one:
https://www.amazon.com/dp/B0C374KVZH?ref=ppx_yo2ov_dt_b_product_details&th=1
Unfortunately this one is a 5V version. It will be a replacement for the old WS2812 strip which is used for Balcony Lighting. With the replacement I am expecting much smother and brighter lighting.
Other PixelBlaze based lighting projects will stay “as is”. Let me see how the replacement will work.
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I am looking at things like https://www.aliexpress.com/item/1005005335051905.html
and https://www.aliexpress.com/item/1005005047701615.html
which have 720 LEDs/m (!!!).
At the latter link, the 4th image says “addressable groups of 36 LEDs”. Sounds like it’s actually 20 very wide pixels/m. Does anyone have any experience with such strips?
I have few of these (bouht them on Amazon) and they are very good for my use cases. The IC density is 20IC/m but each IC drives 12 LEDs. This way the pixel size is about 2 inches long but it lights evenly without any dark spots. Voltage drop at the end of 5m strip at a full white brightness is less than 2v. This very negligible voltage drop was a whole reason why I went with 24V COB strips vs 5V (power injection was not an easy task). However if power injection is not a show stopper I am using 5V COB strips. At this time everything was converted to COB (I don’t like dark spots).
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Thanks! I am impressed with the 12V strips I just got and will consider these 24V COB. I think I have learned something about electricity!
Which one is it?
I did not find any good 12V version in a past. Anything 12V I saw was not impressive considering LED density vs voltage drop (less voltage mins more current and more current means higher voltage drop). But today things could be much better. That is why I am using either 5V (definitely requires power injection) or 24V (no power injection is required) strips. But 5V is a single LED per pixel vs 12 LEDs per pixel for 24V strips. At this time I am considering only COB style strips.
https://www.aliexpress.com/item/1005006884133023.html 3M 144 IP67. Oddly it came with 4 wire JST connections, but … whatever. It works great.
I used 2 strips in series, which adds up to ~6A, but I powered from both ends with 6A since it was easy to hook up. I was happy to see that there was no brightness dropoff when I turned off the power on one end.
Thank you for the info. It looks good but this is not COB style. As of today my choice is only COB style strips (everything already updated to COB) . COB already have a diffuser and could be as narrow as 2.5mm wide (really hard to solder wires but it worth it).
I have made a few projects using COB LED.
You have to be very careful about LED vs Pixel density: a lot of COB strips are advertised as “720 LED/m” or “830 LED/m” !!! But by LED they mean individual color LED, often the actual number of pixels (R+G+B leds) is 3 times less. Be careful.
Then you have the individually adressable density. So far I have seen no INDIVIDUALLY adressable COB LED strip in 12V or 24V. They are always made in a way 1 IC controls a bunch of pixels, so the actual “individual” density is usually 50mm or 70mm, making it much less interesting than the usual 5050 144 pixels/m.
In 5V you can find up to 334 individually adressable pixels/m, but keep in mind that 2m of these limits you at around 40 fps on a Pixelblaze, and 20 fps if you go for 4m.
In terms of power injection, COB strips are much more efficient in my opinion, and simply use less current, so it’s less necessary to inject power. I recommend to make your own measurements as there are quite big differences between the strips i’ve found on AliExpress.
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Yes. This is because a required voltage for the single LED is around 2V. For the 24V strip you need to connect serially 12 LEDs. Because LEDs in COB strips are very small the size of the “12 LEDs Pixel” is only 2 inches (or 50mm). Well, sure this is definitely less attractive than 144pxl/m version but it is OK for the applications if high resolution is not required.
Yes, you are 100% correct. The actual pixel count is a number of ICs. For the 24V COB strips it is usually 20IC/m. Number of LEDs is a very different story. The advertised number of LEDs is 36 but the actual number of physical parts is 12 (R, G, B in one case). This comes to about 2 inches of real pixel size. But what I like about COB - there is no dark spots at all. For the few projects such as Undercabinet Lights, Balcony Lights pixel size does not matter but absence of dark spots is a big deal.
Yes, the LEDs themself are far more efficient and higher voltage means less current, i.e. less voltage drop across the entire strip. For the 5m strip the voltage drop is less than 2V at the far end at a full white brightness. This means no power injection is required.
Highest density 5V COB I bought about a year ago is/was 240LED/m but right now all I can find is 160LED/m. This definitely needs power injection from both ends (and better one more in the middle but this could be skipped).
As far as a frame rate I am OK with 20fps because my wife really hates something moving too fast. Her preference is a (very) slow motion relaxing patterns. Slow patterns are actually acting as a “color therapy” and in fact are recommended by few doctors practicing non-traditional medicine. And I can confirm, this is a very true statement.
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