12V Resistor and 12V Regulated WS2811 Pixels

LawrenceDriveLights

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Hi all,

I noticed some of the commonly used Chinese vendors are now offering for sale both Resistor and Regulated types of 12V WS2811 pixels and there is a little price difference between the different types.

Wired Watts has provided some information regarding this and some pictures to help you identify them.


I am just posting this as some people may be thinking of ordering pixels and it may be useful to know there is a difference in some of the 12V pixels which may be a reason for some price differences.

Also may be a idea to check what type you currently have if you are ordering more pixels for your layout.

I honestly don't know if it is a issue to mix and match the types but maybe be best practice to keep the string all the same type,

I would also specify which type you require when obtaining a quote from your preferred supplier etc just like specifying wire size and pixel spacing etc.

Now this just a little info post so please no responses like "My pixel supplier is best and I get the best price from vendor XYZ"

and please no replies "I use 5V pixels so it doesn't matter" :)
 

David_AVD

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I use 5V pixels .... and 12V pixels. :)

As per chat, I'd say that the regulated type will give you a consistent brightness and colour over a range of voltage.

It's certainly something that should be discussed more here and at the minis.
 

Mark_M

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What is the range of regulated pixels...? Could 12v regulated pixels work off 5v....? It all depends on the voltage regulators cutoff voltage. Might be something I could try with my 12v regulated pixels.
 

Mark_M

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Mark_M, Did you get your answer to this?
I have a 'dead node' which has a data wire come lose and to repair I would lose water proofing.
I will try with this node and then the 100 node string. With my 'dead node' I could also try my luck at the voltage tolerance above 12v.
I have said too many things in threads and forgot about them, whoops! :oops: (I'll make a reminder this time).

Sent from RaspBerry Pi 3B
 

scamper

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What is the range of regulated pixels...? Could 12v regulated pixels work off 5v....? It all depends on the voltage regulators cutoff voltage. Might be something I could try with my 12v regulated pixels.
I would think that the may work off 5v, but maybe not all that well, Reason being the voltage of any regulator must be around 2v higher than the output, once it drops below that, there will be no output. So as led's overate on around 2.2v to 2.7v (depending on colour) you are only just above the 2v minimum, then as you load it up and run down the string with voltage drop, you may drop under the threshold.
 

David_AVD

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Some modern LDO (Low Drop Out) regulators can operate with as little as 50mV - 100mV across them (Vin - Vout).

That said we have no idea what they are using in those pixels.
 

Mark_M

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I have done a little test; will film tomorrow after school.

I have scraped back the resin and found the voltage regulators part identifier. I'll look for a data sheet tomorrow as well.

If you can't wait here is the lowest I can go with some light output, the pixel node it not stable at this voltage!
It acts like a strobe with an off time of [estimate] 2 seconds. I suspect any voltage would be enough to charge the capacitors over time and then illuminate for a moment. Like what @David_AVD said about LDO regulators.
Spoiler content hidden. Log in to see this content.

*Measured with a Fluke 23 digital multi meter at the closest point to the pixel node.
 

Mark_M

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Before I begin I'll strip back more of the resin and measure the resistors in conjunction with the supply in circuitry (hopefully see the SMD part number).
If I can; I'll go cross eyed tracing the circuit schematic.

For the video I will test a few things:
  1. Low voltage dropout with steady operation - Rainbow, single colours and white ramp.
  2. Ambient temperature effect.
  3. Highest voltage before magic smoke.
I aim to conduct all these experiments with a constant ambient temperature.

Any objections, method suggestions or other tests people would like?


I hate to say this; but with more school work i'm likely to film this during the weekend.
 

AAH

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Before I begin I'll strip back more of the resin and measure the resistors in conjunction with the supply in circuitry (hopefully see the SMD part number).
If I can; I'll go cross eyed tracing the circuit schematic.

For the video I will test a few things:
  1. Low voltage dropout with steady operation - Rainbow, single colours and white ramp.
  2. Ambient temperature effect.
  3. Highest voltage before magic smoke.
I aim to conduct all these experiments with a constant ambient temperature.

Any objections, method suggestions or other tests people would like?


I hate to say this; but with more school work i'm likely to film this during the weekend.
Magic smoke :jawdrop:
I'd be interested to see what the quiescent/standby current of the pixel is with both no data going through it and also with data but all zeroes going through.
When testing the dropout voltage the best test in theory should be to monitor the current with a steady state 100% white on it. The current should be around 55mA but may be slightly higher due to the quiescent current of the regulator. In theory the current should remain the same as you wind the voltage down from 12V until you either reach the dropout voltage of the regulator or until you have passed that voltage and you have reached a point where there is insufficient voltage to power the leds fully. At that point the colours could start changing. I'd actually be interested in seeing the voltage at which the current starts changing which I expect is potentially at around 7V and also the voltage at which the operation becomes erratic which could be anywhere from 7V to a potential 3-3.5V.
 

Notenoughlights

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I've just pulled some of my 12V voltage regulator style pixels out of my parts box and put them on an ESPixel stick running at 5V, I don't have any odd flashing, strobing or oddities in colours, they seem to just work fine although they may be a little dimmer than usual but not by any amount you would worry about.

Edit: Just thought I'd try some 12V resistor style, and they work fine too, white is a little blue-ish however. I tried to take a photo, but they just show as white.
 
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Mark_M

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I have the data sheet for the regulator. It's 6.7v that is dropout.
No more spoilers til I film the magic smoke!

I'll ask around for a thermocouple or laser based thempature measurement device. I'll see how well they cope in hot conditions (like 35°C). Thats dependant on if I get a temperature measurement device!
 

AAH

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I have the data sheet for the regulator. It's 6.7v that is dropout.
No more spoilers til I film the magic smoke!

I'll ask around for a thermocouple or laser based thempature measurement device. I'll see how well they cope in hot conditions (like 35°C). Thats dependant on if I get a temperature measurement device!
35C is hot?
With ambient temps in Aus of 40C around Christmas it's likely that with an epoxy insulated pixel and the 9V voltage drop from supply to resistor it's likely the chip temperature on both the reg and WS2811 chip is around 65C and potentially higher.
What regulator is used?
 

Mark_M

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What regulator is used?
AAHhhh....... Spoiler:
Spoiler content hidden. Log in to see this content.

Sadly I haven't acquired a thermocouple or other temperature measurement device. Might have to void that test :(. I really wanted to see their performance in hot conditions like Au.

I could still aim a hair dryer at it, just wont have the temperature reading.
 
Last edited:

AAH

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That is a spoiler. I had hoped that something more exotic was used. Low quiescent and low dropout. About a 3mA quiescent on top of the already inefficient design :jawdrop:
 
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