Broke LED Strip? Help with simple project!


I have recently posted about this simple project and i think I have came to a conclusion that my LED Strip is broke.

So for everything I have,
• One led strip WS28b12 individually addressable that is 5v
• Power Supply rated for 10 amps at 5 volts
• Arduino Nano with FastLED and Adafruit examples
• One 10v 1500μ
• One 470 ohm resistor

When I run 100 different examples nothing happens to the led strip. It wont ever light up. Out of many tutorials I followed, this was the last one I tried Arduino Compatible Nano NeoPixel Controller - Arduino Project Hub

BTW I have two ground pins but im not using one of them.Thats what the extra yellow cable is.
If you have any questions or help id be happy to hear what you have to say!

EDIT So i figured out that if I connect the arduino to my computer then the strip will turn on but if I plug the 10 amp power supply to the board and strip the the strip will turn off. I tried grounding it and everything but the strip still turns off when the power cable touches it.


can you take a picture of how you have everything connected? it might take several close up pictures.

So where in those pictures are the

• One 10v 1500μ
• One 470 ohm resistor

You said you had?

The article linked to in post#0 use the V-in (raw) pin of the Nano to externally power the Nano.

5volt from the external supply on V-in means that the Nano could run on 4volt or less, because of the 1volt dropout of the regulator. That could make the Nano and the data stream unreliable.

You should connect the external 5volt supply directly to the 5volt pin.

So you suggest putting the positive into the 5v pin on the arduino?

Also I took out the resistor because I read that these strips already have them installed. Is that true?



Make sure you have the external supply connected and running when you connect the USB cable to upload data.
Failing to do so might burn out the USB backflow diode of the Nano.
A safer way is to disconnect everything (supply and strip) when uploading new data.

Stupid question.
The example you linked to in post#0 uses D6 as datapin, but you use D3.

Test the Nano, and the pin used with e.g. the 'blink' example and a LED/resistor connected to that pin. Just to make sure it isn't the Nano.
Post the exact code you're using now (inside code tags).

Are you not soldering the wires onto the strip? You always have your finger on the connections during the pictures.

I have made a quick youtube video on my setup if you are confused.

You should never ever wire up a circuit or change the wiring while the power is connected. That is how you damage things.
Never pull out wires when the thing is powered up. The fact that it does something tells you nothing.

Test just the data pin you are using on an LED ( and resistor ).

I agree with Mike’s hot-plug warning,
and you were back-powering the LED strip through the USB backflow protection diode and 5volt regulator of the Nano.
Bad for both parts, and the strip would only have been powered with <=4volt (only red LEDs working).
Read the warning in post#8 again.

Thank you I am very new to this.. How do you think I could solve my problem?

Thank you I am very new to this… How do you think I could solve my problem?

Test the Nano (that data pin) with everything disconnected, with a LED+resistor, as explained in post#10.
So you know the Nano isn’t damaged.

Reload the strip sketch, ofcourse with everything (external supply and strip) still disconnected.

Disconnect the USB lead.

Connect the strip (with cap) power and ground to the external supply (properly soldered or with a joiner block).
External supply should ofcourse be OFF.

Connect ground and data (with resistor) of the strip to the Arduino.
Don’t connect strip supply (5volt) to the Nano yet.

Connect the USB lead the laptop.
Connect the external supply to mains power.

If the strip is not working, then it could be the code (post it here after you have read the forum rules).
Or the first LED of the strip is blown from your hot-plugging.

If it’s working properly, then you can try powering the Nano also from that 5volt supply (the 5volt pin).
Unplug the external supply before you change over, and the USB lead should ofcourse stay unplugged if you do so.

I followed your directions. First, I used a brand new Arduino Nano. I used one led I had laying around that only turns blue and plugged it in to the arduino. The arduino had the FastLED blink example code set to it. It blinked using the blink example. When I used my led strip, nothing turned on. I figured I ruined the second LED. Then I soldered the third LED then I plugged it in and it still didnt work.

That doesn't sound like you followed Wawa's advice.

When I used my led strip, nothing turned on.

You had uploaded some FastLED code, if not why, if so why have you not posted this like you were told to do?

I figured I ruined the second LED.

No one mentioned a second LED how could you have ruined that? The LEDs in the strip act like a chain taking the data signal into one LED and passing it out to the next in the chain. If you have blown the first LED then it can fail in a way where it can not send the data into the second LED. So you have to remove that first LED by cutting it out of the strip and wiring up to what was your second LED but has now become your first.

Then I soldered the third LED then I plugged it in and it still didnt work.

Is that the third on the strip? Have you removed the other two? You can't solder the data wire to a mid point in an LED chain because your output data will fight the output data of the previous LED chip.