WS2812B ambilight strips not lighting up

Heya all, I'm pretty new to Arduino and led strips so as my first project I chose to DIY ambilight for my computer.

I bought all the parts and followed this tutorial:

I've cut my strips to fit my monitor, attached the L brackets and connected everything according to the diagram.

The problem is: none of my leds light up. They have never even lit up as a matter of fact. And I'm lost on what to do to test what's wrong, I used my multimeter and can measure 5V everywhere in my strip, so I'm pretty sure the connections are fine.

I don't know how I'd measure if the data is actually going over the datarail or if my leds are blown, or the rail is blown.

Could anyone grant me some insight on these topics? Thanks!

P.S. if you need more information or a picture of my set up, let me know.

What we need you to do is to read the forum guide in the sticky post. It's at the top of every forum section. It will tell you what we need in order to be able to help you.

I appreciate the reply, but I believe I have checked pretty much everything on the common issues page.
Could you specify what you mean?
Thank you!

Have you read and followed this General Guidance and How to use the Forum - LEDs and Multiplexing - Arduino Forum, which is located at the top.... See post#1

I did. It did not solve the issue.

dankntn:
I did. It did not solve the issue.

Well, then the issue might lay with the properly formatted code in code tags you posted; line 644. Also, from looking at the schematic of your circuit, the issue could also be the connection you did not make?

dankntn:
I did. It did not solve the issue.

You are correct, of course. Reading them will not solve the issue. But following them might enable us to help you solve the issue.

EDIT: I think I see what's happened here. In their well-meaning efforts to improve the help offered by this forum, changes made by the moderators have had the unfortunate side effect of distracting attention even further from the most basic advice new forum members very often need. Advice on how to ask for help, in a way which enables others to help them (and without relying on those others having psychic powers of any sort).

@dankntn, can I point you at a specific part of a page I suspect you haven't read yet, given your responses so far?

Idahowalker:
Have you read and followed this General Guidance and How to use the Forum - LEDs and Multiplexing - Arduino Forum, which is located at the top.... See post#1

There is no "post#1". That is a locked original with no replies, so no reply "#1". :astonished:

If you actually mean to point to the link to "Learn How To Use The Forum," then you should post that link itself! So that people do not get fatigued when they fantasise they have followed sufficient of the steps, it is as well to refer specifically to point no. 7 regarding posting code in a usable manner. :roll_eyes:

Have you tried just lighting one LED in the strip? Just use fastled or the Adafruitneopixel library and just get one led to light using one of the examples provided for by the library.