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Topic: non working ws2812B (Read 890 times) previous topic - next topic

Derek_Foppen

i know a similar question has been asked, but that isn't really the issue here.

i had my 144 ws2812B working for maybe 5 mins. then i blew up the powersupply(sort of, it generated too much heat). and now a few random LED's are just shining green. and i cant change any of the leds. but now the odd part comes. even when my arduino is unplugged those LED's remain green. when I remove and reapply the powercable the exact same LED's are green.

ive tried different arduino's but none can address a single LED. what ever sketch i upload none are working. and I've got a solid 4.62V output from the PSU. but, i haven't got a resistor betweed Din and pin 9. when i was finished with soldering i found out i forgot it.

so my question is, Could the first led be damaged and causing this odd behavior. or did the whole strip die?

(I can't just cut the strip since it the waterproof version.)
and yes it's bought in China.





Grumpy_Mike

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Could the first led be damaged and causing this odd behavior.
Yes.
But equally you could have blown he whole strip, it depends what your power supply did when you fried it.

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(I can't just cut the strip since it the waterproof version.
Yes you can, it is quite soft and cuts with a scalpel. You can seal it up with silicon adhesive.

Derek_Foppen

Yes.
But equally you could have blown he whole strip, it depends what your power supply did when you fried it.
i dont think so, some of the LED's still light up when they've got power. expect they're always green and uncontrollable..

Yes you can, it is quite soft and cuts with a scalpel. You can seal it up with silicon adhesive.
did that, and did the Din test(going across the whole strip placing the wire attached to 9 and the Din of the LED). some of the light start flikkering like the blink file some don't respond. but again those who blink are also green.



Grumpy_Mike

#3
Mar 07, 2018, 09:06 pm Last Edit: Mar 07, 2018, 09:07 pm by Grumpy_Mike
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i dont think so, some of the LED's still light up when they've got power.
That means absolutely nothing. I have a totally FUCT ( Further Use Completely Terminated ) neopixel matrix and some LEDs light or flicker when power is applied to it. I know it is FUCTed because I accidentally attached a 12V power supply to it instead of a 5V one. When a part is dead it is not always unresponsive, it sometimes partially works but not enough to be useful.

Wawa

i dont think so, some of the LED's still light up when they've got power. expect they're always green and uncontrollable..
And... you're about to blow up the Nano as well.
There is a "500mA absolute max" diode between the USB supply and 5volt pin.
Powering more than eight (8*60mA) addressable LEDs from that 5volt pin will send that diode to silicon heaven.

What voltage did you use on the input of that linear 5volt supply.
144 LEDs could use 8.5Amp. That's 8.5watt for every volt above 5volt.
= ~60watt with a 12volt input and an all white strip.
A 2N3055 without heatsink might be able to dissipate ~3watt.

Use a 5volt/10Amp switching supply for 144 LEDs.
Leo..

Derek_Foppen

#5
Mar 08, 2018, 05:38 pm Last Edit: Mar 08, 2018, 05:44 pm by Derek_Foppen
That means absolutely nothing. I have a totally FUCT ( Further Use Completely Terminated ) neopixel matrix and some LEDs light or flicker when power is applied to it. I know it is FUCTed because I accidentally attached a 12V power supply to it instead of a 5V one. When a part is dead it is not always unresponsive, it sometimes partially works but not enough to be useful.
so i fuct(ed) up the leds. after discussing the matter with one of my teacher he mentioned "the moment an power transistor (2n3055) overheats it wil cross the referred current, 5v in your case. and it could supply up to 19.4v. but you dont know if that happened, since you model still works"

i guess I'll have to cut the whole strip to pieces and test 1 LED at a time. it was only €2.

and ive ordered a new strip, 5m this time.


That means absolutely nothing. I have a totally FUCT ( Further Use Completely Terminated ) neopixel matrix and some LEDs light or flicker when power is applied to it. I know it is FUCTed because I accidentally attached a 12V power supply to it instead of a 5V one. When a part is dead it is not always unresponsive, it sometimes partially works but not enough to be useful.
And... you're about to blow up the Nano as well.
There is a "500mA absolute max" diode between the USB supply and 5volt pin.
Powering more than eight (8*60mA) addressable LEDs from that 5volt pin will send that diode to silicon heaven.

What voltage did you use on the input of that linear 5volt supply.
144 LEDs could use 8.5Amp. That's 8.5watt for every volt above 5volt.
= ~60watt with a 12volt input and an all white strip.
A 2N3055 without heatsink might be able to dissipate ~3watt.

Use a 5volt/10Amp switching supply for 144 LEDs.
Leo..
im using an old laptop charger to power the psu, 19.4V and 3.65A, is 70W. so that should be enough. since 144*0,060*5= is only 43.2 Watt.

after doing some tests i found out the 2n3055 survived it. and yes it needs an heatsink. this is just a proto anyways.(ive got  a pc/cpu heatsink for him ready)

and we fried the nano years ago at school, so it hasnt got the Schottky diode to help it protect its 5V.. i only use it in proto's and with fused cables.
but i tested the strip with several psu, but only those 6 leds would light up. so i knew i would damage the arduino. and i used the blink test program. so that would light up only 1 LED.

Grumpy_Mike

#6
Mar 08, 2018, 08:40 pm Last Edit: Mar 08, 2018, 09:49 pm by Grumpy_Mike
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19.4V and 3.65A, is 70W. so that should be enough. since 144*0,060*5= is only 43.2 Watt.
You can't say that, you need the voltage and current in values that your component needs them. You can only talk in power terms if you are producing the current and voltage you need using a switching regulator and I don't think you are.

Your regulator uses a 2n3055 transistor as a linear regulator so the current drawn from the power supply is going to be the same irrespective of the voltage you regulate it to.

So 1A at 5V regulated by a linear regulator is going to be 1A at 19V from your power supply. So it takes 19W from your power supply to provide 5W of useful power in your load. The difference in power 19 - 5 = 14V @ 1A = 14W is burned off by the regulating transistor. Which is why it gets hot, and it could be that an infinite heat sink is not sufficient to burn off this power. It is all to do with the thermal resistance between chip and case and case and ambient. You have no control over the chip to case thermal resistance, you find that in the data sheet.

For more information see:- http://www.thebox.myzen.co.uk/Tutorial/Power.html and the examples page found off that.

Derek_Foppen

You can't say that, you need the voltage and current in values that your component needs them. You can only talk in power terms if you are producing the current and voltage you need using a switching regulator and I don't think you are.

Your regulator uses a 2n3055 transistor as a linear regulator so the current drawn from the power supply is going to be the same irrespective of the voltage you regulate it to.

So 1A at 5V regulated by a linear regulator is going to be 1A at 19V from your power supply. So it takes 19W from your power supply to provide 5W of useful power in your load. The difference in power 19 - 5 = 14V @ 1A = 14W is burned off by the regulating transistor. Which is why it gets hot, and it could be that an infinite heat sink is not sufficient to burn off this power. It is all to do with the thermal resistance between chip and case and case and ambient. You have no control over the chip to case thermal resistance, you find that in the data sheet.

For more information see:- http://www.thebox.myzen.co.uk/Tutorial/Power.html and the examples page found off that.
aha, thank you for your information. I see this project has failed due to lack of knowlegde. I'll retry this project when I've got new components(the heatsink issue has been fixed).
And I've got a new project.

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