Arduino Forum

Using Arduino => LEDs and Multiplexing => Topic started by: sblantipodi on Jan 17, 2019, 09:46 pm

Title: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 17, 2019, 09:46 pm
Hi guys,
I used for two months a 95 LED strup (60 led per meter cutted) WS2812B 5V on my ESP8266

This was my setup.

(https://i.postimg.cc/KzKhrHTW/pc.jpg)

after some months I wasn't able to control the led anymore. I tried everything, cutting the first led, the second one, the third one. The led strip was dead, only some leds lighted up and every others shutdown.

I tried everything and the strips seemed dead so I bought another strip and connected only 10 leds to it just to give it a try. same things, the strip was dead.

So I decided to try a different approach with this schema
(https://i.postimg.cc/vB1DgXZY/particle.png)

basically I used a logic converter to up my 3.3V digital pin to 5V. I also added a resitance of 470omh.

nothing, I can't control the strip. strip light up but leds are out of control, some leds off and some others with some strange color.

power supply seems to be in a good state and connection seems to work well.



should I give up?
what can it be?
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: CraigMurphy on Jan 17, 2019, 11:10 pm
Replace parts with known good ones. Find the bad part.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 17, 2019, 11:12 pm
Replace parts with known good ones. Find the bad part.
I replaced the ESP, I replaced leds, I replaced the logic level converter, I replaced the capacitor, the resistor,
the only part I haven't replaced it the power supply.

can it be the power supply?
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 18, 2019, 01:34 am
I tried changing the power supply. Still I can't drive the led.
LEDs lit up but I can't drive them.

Can it be a software problem?
Is it possible that the same sketch doesn't work anymore after some libraries update I have done in the Arduino IDE?

I really don't know what to think
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: PaulRB on Jan 18, 2019, 08:10 am
You should have a resistor connected to the data line. I can only see that in your first picture. You should also have a large cap, e.g. 1000uF, across the power supply lines, close to the start of the strip.

Instead of your logic convertor module, you can try a 74hc14 chip. Power the chip with 5V. Each chip contains 6 inverter gates. You will need to use two gates, connected in series. As with any chip, put a 0.1uF cap across the 5V & ground pins, close to the chip.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 18, 2019, 08:23 am
You should have a resistor connected to the data line. I can only see that in your first picture. You should also have a large cap, e.g. 1000uF, across the power supply lines, close to the start of the strip.

Instead of your logic convertor module, you can try a 74hc14 chip. Power the chip with 5V. Each chip contains 6 inverter gates. You will need to use two gates, connected in series. As with any chip, put a 0.1uF cap across the 5V & ground pins, close to the chip.
I tried with the resistor and the capacitor.
the problem is that now it doesn't work even with the simple schema that it is always worked.

can it be a software problem?
sketch is not changed but I updated libraries. can it be a problem of software that it compile ok but than does not work for some new libraries I installed?
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: PaulRB on Jan 18, 2019, 04:30 pm
Your first pic shows a Nano. This is a 5V Arduino. The others show esp-based Arduino which are 3.3V. This could be the reason.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 18, 2019, 08:39 pm
Your first pic shows a Nano. This is a 5V Arduino. The others show esp-based Arduino which are 3.3V. This could be the reason.
pictures shows different devices but I always used the ESP8266 with wemos d1 mini.

I finally finded the problem. My power supply, I don't know why, started to give 13V instead of 5V.
he burned my strips as soon as I attached them.

finally, I finded the reason. thank for the support guys!
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 18, 2019, 08:48 pm
just the last question.

is 220ohm enough if using an ESP8266 with a logic level converter that bump the GPIO from 3.3V to 5V?
can you explain me the reason why use a resistence for the GPIO and a capacitor for the power ?
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 18, 2019, 11:03 pm
The resistor stops reflections and protects the input, especially if the signal is applied with no power to the strip.
The capacitor stabilise the voltage and prevents damage to the power supply.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: PaulRB on Jan 18, 2019, 11:08 pm
The capacitor I can explain. Even with thick wires, there is some resistance. This limits the current flow. That limits the speed that voltage can return to normal when the current suddenly changes, like when a bunch of pwm controlled LEDs switch on or off. When the voltage cannot return to normal quickly, this affects the data signal, indirectly, because the voltage of the data signal is always compared, by the chips on the strip,  to the supply voltage. If the data voltage cannot quickly return to normal, the data gets, or appears to be, corrupted. The capacitor near the start of the strip acts as a local reservoir of charge, so charge does not have to be transferred over the long wires, there is a local supply available. So the power to the strip remains more steady, and the data signal is less likely to appear corrupted.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 19, 2019, 01:14 am
Thanks for the answer guys. I really appreciate your help

Another questions if possible.
Why they say that a 220ohm / 470 ohm resistance is ok?

Should I choose 220 or 470?
I choosed 220ohm for esp8266 + logic level converter from 3.3 to 5v, was I wrong?

Another question. I have 95 LEDs ws2812b with smd5050.

Should I power the strip on two side or one side is enough?

Thanks
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 19, 2019, 01:35 am
Quote
Why they say that a 220ohm / 470 ohm resistance is ok?
It offers a good balance between protection and not cutting the drive voltage down too much. Mainly from imperial experiments.

Powering from both sides is always preferable if possible.

Quote
I choosed 220ohm for esp8266 + logic level converter from 3.3 to 5v, was I wrong?
You should always have the resistor the 5V side of the of the converter.

I am not convinced that those I2C converters are fast enough for Neopixel driving.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Paul__B on Jan 19, 2019, 05:34 am
Mainly from imperial experiments.
While poor old Phil may have been driving Land Rovers until yesterday (and I strongly suspect will not be driving them any more), I would be distinctly surprised if any of the family knew what an Arduino or WS2812 was.

empirical

I am not convinced that those I2C converters are fast enough for Neopixel driving.
Sounds dodgy.  A 74HCT14 (http://www.ti.com/lit/ds/symlink/sn74hct14.pdf), or even a 74HC14 (http://www.ti.com/lit/ds/symlink/sn74hc14.pdf) would be far more appropriate with two gates in series.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 19, 2019, 09:34 am
Quote
empirical
Dyslexia rules KO.  :)
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 19, 2019, 12:03 pm
It offers a good balance between protection and not cutting the drive voltage down too much. Mainly from imperial experiments.

Powering from both sides is always preferable if possible.
You should always have the resistor the 5V side of the of the converter.

I am not convinced that those I2C converters are fast enough for Neopixel driving.
Thanks for the answer mike
How.can I see if they are fast enough?
If seems that my ambilight reacts well to movies and multimedia in general. Should I check something? Thanks
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: PaulRB on Jan 19, 2019, 12:27 pm
How.can I see if they are fast enough?
If the standard example sketches for FastLED or Neopixel libraries run normally, and the patterns and colours displayed are as expected, then the converter is fast enough.

These converter modules are designed for use with i2C and similar signals, which have a data rate of 100KHz or perhaps 400KHz. WS2812B leds use a data rate of 800KHz. I found that when I used these adaptors for LED strip purposes, the strips displayed colours and patterns correctly, but if I touched certain contacts on the adaptor with my fingers, the strips would flicker, freeze and not show the correct colours & patterns. As soon as I removed my fingers, the patterns would return to normal. This indicated that the signal to the strip was only just good enough. Mike suggested that I should try a 74hc14 chip instead of the adaptor, and I found this was much more stable, because it did not react in any way to being touched - the colours and patterns remained stable.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 19, 2019, 01:08 pm
If the standard example sketches for FastLED or Neopixel libraries run normally, and the patterns and colours displayed are as expected, then the converter is fast enough.

These converter modules are designed for use with i2C and similar signals, which have a data rate of 100KHz or perhaps 400KHz. WS2812B leds use a data rate of 800KHz. I found that when I used these adaptors for LED strip purposes, the strips displayed colours and patterns correctly, but if I touched certain contacts on the adaptor with my fingers, the strips would flicker, freeze and not show the correct colours & patterns. As soon as I removed my fingers, the patterns would return to normal. This indicated that the signal to the strip was only just good enough. Mike suggested that I should try a 74hc14 chip instead of the adaptor, and I found this was much more stable, because it did not react in any way to being touched - the colours and patterns remained stable.
I'm waiting the 74hc14 as per mike suggestion, in the mean time using logic level converter, I will keep you posted if I will encounter some problems with it.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 19, 2019, 06:48 pm
it seems that ambilight does not suffer from problems using the logic level converter.
probably because ambilight sends a signal every 15ms so it doesn't need fast response? in any case I am waiting for 74hc14.


another question if I can...

currently I am using a schema similar to this:
(https://i.postimg.cc/DySnK26H/components-level-Shift-Layers02.jpg)

I have an
- ESP8266 on a wemos d1 mini lite
- logic level converter
- 220ohm resistance on the GPIO
- 1000uf 16V capacitor on the 5V line.

I noticed a strange thing though...

If I connect the power to the strip, and than connect the ESP to the PC, monitor blink black and then return the image.

Is this a signal of some malfunctioning? I don't want to burn the pc.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: PaulRB on Jan 19, 2019, 07:36 pm
Quote
because ambilight sends a signal every 15ms so it doesn't need fast response?
No, the update rate is not relavent here. The doubts about the speed of the level convertor concern things that happen 1,000 to 10,000 times faster than the update speed. The concerns are about the speed that the signal between the Arduino pin and the first led in the strip can change from a 0V to 5V and back again. If those signals cannot change fast enough, then the data will be corrupted and the strip will not be able to receive it correctly, because the 0s and 1s of the digital data are transmitted by different timings of the transitions from 0V to 5V and back to 0V again.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: PaulRB on Jan 19, 2019, 07:50 pm
Quote
monitor blink black and then return the image
I do not know what could cause that. I am also concerned that the pc could be damaged.

Search your circuit for any possible short circuit. It may be that a short circuit could be causing to much current to be drawn from the usb port.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 19, 2019, 10:27 pm
Quote
If I connect the power to the strip, and than connect the ESP to the PC, monitor blink black and then return the image.
Connecting a PC to an Arduino while it is running will reset the Arduino. Best not to connect anything once it is powered up.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 19, 2019, 10:28 pm
I do not know what could cause that. I am also concerned that the pc could be damaged.

Search your circuit for any possible short circuit. It may be that a short circuit could be causing to much current to be drawn from the usb port.
(https://i.postimg.cc/vHvtFM45/ambilight-bb.png)
this is the final image of my exact circuit.

there is no short on the circuit but probably I'm sharing 5V via usb from the esp and the pc.
how can I "save my PC"?
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Paul__B on Jan 19, 2019, 10:54 pm
Please be specific.  Which monitor "blinks black" when you plug what into what and what does it show when it comes back?
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 19, 2019, 11:53 pm
it's incredible...
I have a power strip. on this power strip is connected the monitor, the PC and the 5V power supply I use to power my leds.


now I have the PC, the monitor, the 5V power supply connected to the power strip.
5v power supply is disconnected from the arduino project I posted in the picture in the previous post.
ESP is not connected to the PC usb.

now if I connect the 5V power supply to the 2 pin connector of my arduino project,
MONITORS BLINK :O :O :O :O

how can it be possible? it blink even if the usb is disconnected as soon as I connect the 5v power supply to the 2 pin connector :O

than if I connect the PC USB to the esp the PC monitor blinks again.

than the strip works correctly.

what can it be?
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 20, 2019, 10:53 pm
I add a question

Is is safe to power LEDs from an external power supply and power the esp via pc usb to use serial communication with the microcontroller?

Is this normal or we need some protection like usb isolation?

Title: Re: WS2812b led strip and arduino, should I give up?
Post by: CrossRoads on Jan 20, 2019, 11:07 pm
Yes, that is safe. Be sure to connect the GNDs together.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 20, 2019, 11:15 pm
Yes, that is safe. Be sure to connect the GNDs together.
Thanks for the answer ...
But if it's safe why monitor blink when I connect the esp to the usb? :)
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 20, 2019, 11:33 pm
Quote
But if it's safe why monitor blink when I connect the esp to the usb? :)
Once you tell us exactly what you mean by monitor blink we would stand a chance of telling you. But as far as I am concerned your explanations are not very good.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 20, 2019, 11:48 pm
Once you tell us exactly what you mean by monitor blink we would stand a chance of telling you. But as far as I am concerned your explanations are not very good.
Pc monitor goes black for a second and then return to normal.

That's all but it's a clear sign of something not working correctly. Am I wrong?
If I disconnect the 5v leds power supply I don't see any monitor blinking
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 21, 2019, 12:20 am
Quote
Pc monitor goes black for a second
So is the monitor connected to a mains input that includes a ground connection? Have you checked that the ground in your home wiring is actually bonded to the real ground?

You could have some faulty wiring causing a problem with your earth leakage currents.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 21, 2019, 12:47 am
So is the monitor connected to a mains input that includes a ground connection? Have you checked that the ground in your home wiring is actually bonded to the real ground?

You could have some faulty wiring causing a problem with your earth leakage currents.
Yes monitor is connected to mains with good ground.
Real ground.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 21, 2019, 02:01 am
Then you are wrong about something, how did you check this? Have you had the monitor PAT tested recently?

As your computer does not reset there would seem to be nothing wrong with that and no danger to it. But connecting power supplies when things are powered up is a big no no in electronics as I have told you before.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 21, 2019, 09:17 am
Then you are wrong about something, how did you check this? Have you had the monitor PAT tested recently?

As your computer does not reset there would seem to be nothing wrong with that and no danger to it. But connecting power supplies when things are powered up is a big no no in electronics as I have told you before.
Home is new and the electrical wirings are new so the ground should be ok.
In Mike I trust so if you say that is ok it's ok but I still don't understand why the monitor goes black for one second.

In any case I will not connect things if pc is powered on anymore.

Thanks
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 21, 2019, 10:18 am
Quote
but I still don't understand why the monitor goes black for one second.
The monitor goes black because something is disturbing the monitor circuit. It is not affecting the PC otherwise the PC would reset, as they tend to do at the slightest opportunity.
The problem occurs when a second supply is connected. This second supply is floating with respect to the monitor and so when it is connected the ground of the power supply and the ground on the monitor are brought to the same potential. This causes a very short inrush of current which disturbs the monitor's operation. The result is that some protection circuit in the monitor shuts it down. Then the inrush stops as the two supplies are now equalised and the monitor comes on.

Just as a test remove the LED strip and just connect the power supplies' negitave terminal to the rest of the circuit. It should still happen.

I didn't ask before but I am assuming the monitor is a CRT one.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 21, 2019, 10:41 am
The monitor goes black because something is disturbing the monitor circuit. It is not affecting the PC otherwise the PC would reset, as they tend to do at the slightest opportunity.
The problem occurs when a second supply is connected. This second supply is floating with respect to the monitor and so when it is connected the ground of the power supply and the ground on the monitor are brought to the same potential. This causes a very short inrush of current which disturbs the monitor's operation. The result is that some protection circuit in the monitor shuts it down. Then the inrush stops as the two supplies are now equalised and the monitor comes on.

Just as a test remove the LED strip and just connect the power supplies' negitave terminal to the rest of the circuit. It should still happen.

I didn't ask before but I am assuming the monitor is a CRT one.
if I remove the LED strip and just connect the power supply, nothing change, monitor goes black for a second.
the monitor is a new LCD connected via display port to a dedicated gpu
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 21, 2019, 11:31 am
do you think that something like this:
https://www.adafruit.com/product/2107

should help preventing this problem and making my computer "more safe"?

is there someone who is using USB Isolator here with an ESP? Does it work well?
Title: WS2812b led strip and arduino, never give up?
Post by: Paul__B on Jan 21, 2019, 12:15 pm
The thing is this.

We don't know what you are doing wrong, despite all the back-and-forth questions.

If we can ever fathom what you are doing wrong then we could tell you not to do it, but so far we can't, so we cannot recommend some random device.

So far I don't think we know exactly what your 5 V power supply is, and a detailed, precisely focused photograph of your whole arrangement in bright, uniform light would be most illuminating.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 21, 2019, 12:56 pm
Quote
do you think that something like this:
https://www.adafruit.com/product/2107

should help preventing this problem and making my computer "more safe"?
No I imagine the problem will still be there because their is no indication that their is anything to do with the USB connection.

Just power the Arduino separately and try the test again.

I quite agree with Paul__B in what he says.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 21, 2019, 11:52 pm
(https://images-na.ssl-images-amazon.com/images/I/61XUBDToCpL._SL1200_.jpg)

this is is the power supply for the led strip.

and this is the build

(https://i.postimg.cc/ZqJj25Cg/IMG-20190121-203611.jpg)

(https://i.postimg.cc/3RnqnD1n/IMG-20190121-194531.jpg)

if you need more info, I'm here.

a more clear graph of the connections:
(https://i.postimg.cc/vHvtFM45/ambilight-bb.png)
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 22, 2019, 06:48 am
Thanks for that, it is gives a better understanding of what you have, your construction looks quite good.

I am not sure how much reliance to put on all those declarations of conformity on that power supply but the big one that is missing is the UL mark. It is not surprising as it is perhaps the hardest one to obtain with respect to a power supply. UL is largely driven over concerned with the device starting fires, hence the name Underwriters Laboratory, it arose from insurers wanting to minimise their risk. I do know that UL has a much stricter limit on the earth leakage current than some of the others like CE. I am not saying go for a UL rated power supply and it will solve the problem, they are a lot more expensive and the UL rating mark might be false on Far East designs.

What it doesn't change is my guess that the problem is probably due to earth leakage and the best bet is to have things connected up before applying the power. I know this means powering down then up before making changes to things, but that is what you should do anyway. Even plugging a monitor into a computer that is running can damage things. Their are things you can plug into a computer when it is running, like USB but they have been specifically designed to be "hot swapable", these designs connect the power rails before connecting signals.

I have a similar problem with the Raspberry Pi, you can't plug many things into the GPIO pins without resetting the computer. In the case of the Pi that is a bad thing, because its main storage is an SD card, and unexpected interrupts runs the danger of destroying the card. And being Linux the boot up process is not swift. 
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 22, 2019, 09:33 am
Thanks for that, it is gives a better understanding of what you have, your construction looks quite good.

I am not sure how much reliance to put on all those declarations of conformity on that power supply but the big one that is missing is the UL mark. It is not surprising as it is perhaps the hardest one to obtain with respect to a power supply. UL is largely driven over concerned with the device starting fires, hence the name Underwriters Laboratory, it arose from insurers wanting to minimise their risk. I do know that UL has a much stricter limit on the earth leakage current than some of the others like CE. I am not saying go for a UL rated power supply and it will solve the problem, they are a lot more expensive and the UL rating mark might be false on Far East designs.

What it doesn't change is my guess that the problem is probably due to earth leakage and the best bet is to have things connected up before applying the power. I know this means powering down then up before making changes to things, but that is what you should do anyway. Even plugging a monitor into a computer that is running can damage things. Their are things you can plug into a computer when it is running, like USB but they have been specifically designed to be "hot swapable", these designs connect the power rails before connecting signals.

I have a similar problem with the Raspberry Pi, you can't plug many things into the GPIO pins without resetting the computer. In the case of the Pi that is a bad thing, because its main storage is an SD card, and unexpected interrupts runs the danger of destroying the card. And being Linux the boot up process is not swift.
Thanks for the answer and the patience.
This will be my last question to not bother you.

Suppose that there is an earth leakage, how connecting things before powering up them all can be safier?
Doesn't the problem remains?

Thanks for the explanations and the patience :)
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 22, 2019, 10:31 am
Quote
Suppose that there is an earth leakage,
There is earth leakage in all power supplies, it just simply a matter of how much.

Quote
how connecting things before powering up them all can be safier?
Because when they are connected together before powering all the elements of the circuit are at the same potential. Then when they are powered the earth leakage currents start all at the same time so there is not a sudden change in the current. It is the sudden change in the current that causes a change in voltage which is what I think is upsetting your monitor.

You could say it is hidden in the start up process, the monitor is not yet on so you don't see it go off. That is a bit of an over simplification but not too far from what happens.

Quote
This will be my last question to not bother you.
Don't worry, keep asking about what you don't understand.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 22, 2019, 10:56 am
Don't worry, keep asking about what you don't understand.
Thanks for making arduino's world a better place Mike,
I really appreciate your help. In a world where internet is full of shitstorms and trolls I'm really glad to find people like you and the others here :)

for what it worth here the results of those circuit.

ambilight video 1, youtube video (https://photos.app.goo.gl/ezXHVFBcurkY2P8DA)

ambilight video 2, AC Odissey gameplay (https://photos.app.goo.gl/HqjRdwETmvw5j7wv9)

it's pretty cool :)
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Paul__B on Jan 22, 2019, 11:52 am
Not exactly mentioned so far, but it is generally the case that a power supply which has a ground lead on the AC cord, will also have that ground lead connected to the negative of the output.  Which is why Mike is suggesting that it has something to do with the odd behaviour.

You can verify that connection with a multimeter.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 22, 2019, 11:55 am
Not exactly mentioned so far, but it is generally the case that a power supply which has a ground lead on the AC cord, will also have that ground lead connected to the negative of the output.  Which is why Mike is suggesting that it has something to do with the odd behaviour.

You can verify that connection with a multimeter.

I'm sorry, probably I'm too noob to understand it, can you explain in different words where should I connect the multimeter?
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Paul__B on Jan 22, 2019, 12:50 pm
You will almost certainly see continuity when you probe between the ground pin on the mains power input and the sleeve (negative) of the output connector.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Grumpy_Mike on Jan 22, 2019, 02:58 pm
Quote
for what it worth here the results of those circuit.
You might find this hard to believe but I have never seen an Ambilight in action before thanks.

Yes with a power supply with that much current output you are likely to have a 3 terminal mains connector. However in my experance the outputs still float rather than being connected to ground.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: Paul__B on Jan 22, 2019, 10:01 pm
Yes with a power supply with that much current output you are likely to have a 3 terminal mains connector. However in my experience the outputs still float rather than being connected to ground.
Which is why we want to know whether it is connected or not as part of the forensic trail.

To have the secondary not grounded, the transformers need to comply with "double insulation" standards even though it is not so marked as it has a ground pin.

Regarding the "that much current output", almost all 19 V laptop power bricks with a three pin plug do have the output grounded.
Title: Re: WS2812b led strip and arduino, should I give up?
Post by: sblantipodi on Jan 23, 2019, 11:03 am
my ignorance in this matter doesn't let me understand well what you are saying.
should I change my power supply for a better one?