Ground connections on multiple LED strips

Using Arduino General Electronics
1

Hello, I’m doing a project with multiple one meter strips of neopixels and prototyping with two strips to get the wiring correct before I scale up to six or seven. I’m powering each strip separately with a 12v battery pack and running it with a Nano Every, powered with its own 9v.

I read that all the grounds for the LED strips should be connected so I have both battery pack grounds tied together with connections to the ground lead on each strip. The 12v lead from each pack goes directly to the strip it powers.

I have the data signal from my Nano going into the data lead on my strip and then connecting to the next strip. The ground for a pot I have connected to the arduino along with the second ground connection on the arduino is tied into the common ground on the battery packs. I thought that would work, but it does not. I’m guessing I need to separate the grounds and tie the data line back to the arduino’s ground, but I’m not sure. It seems like it shouldn’t matter since all grounds are connected.

I’ve run several projects with the code I’m using, but they’ve all been driving just a few neopixels powered directly from the board. This is the first time I’ve powered one this way. Also first time I’ve connected capacitors across the + and - leads of a strip. Maybe that’s it?

2

What does or doesn’t happen that shouldn’t or should?

Draw a schematic, even with a pencil. It all sounds plausible.

Post your test code that just checks the strips and nothing else. Perhaps even an example program you did not write.

a7

3

Hi,
Have you got the gnd of the Nanoevery connected to the gnd s of the strips supply?
The digital signal needs a gnd reference to be interpreted by the strip logic circuits.

Tom... :grinning: :+1: :coffee: :australia:

4

The claim has been made. :wink:

a7

5

Hi,
Have you just tried to get ONE strip working?
Forget the other ones, just prove your hardware and basic code.

Tom... :grinning: :+1: :coffee: :australia:
PS.

Needs to be a more point type description, rather than story type description. :woozy_face:

6

Hmm, I’m wondering if this is where one of those “schematic diagrams”would be helpful.

a7

7

After some reading I think my problem is that the data signal is drowning out because of the star configuration of all my ground connections. I’ll run the ground directly from the strip back to the arduino and do some tests today.

8

That sounds very very unlikely. The way you connect the groupings will have no effect on the signals, unless the strip is a long way from the Arduino.

Have you a resistor in the data lead?
Are the caps as close to the strip as possible?
Are you feeding the data in at the right end?

9

Hi,

Make all your strips gnds star connection at their supply gnds, then connect the NanoEvery gnd to the star point.
The aim is to keep the load gnd return current to the strips out of the current flow gnd return of the NanoEvery.
We need to see a circuit diagram and your code.
As I asked previously, have you been able to just get ONE strip working, if not then forget all the others and use ONE strip to prove your code and hardware.

Thanks.. Tom... :grinning: :+1: :coffee: :australia:

10

Quick update: I’ll try and upload a schematic and the code when I have time. I changed two or three things so I can’t nail down which one it was yet. I eliminated one strip and battery pack first. That didn’t change anything. I simplified the ground so the data signal might be more clear and I think that did it because the strip is lighting and doing the thing it’s supposed to as far as the display is concerned. The original strip had a silicon casing that I had pulled off and that may have damaged it so I switched it out for a new unmolested one. In any event, it’s working now. Thanks for all the help. I’ll update later and see if I can get multiple strips running.

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