So basically my LEDs are working just fine when only using the 5v + GRD pin of my Arduino Uno, so I know the program isn't the problem. Here is a picture:
But as soon as I disconnect the 5v + GRD from my Arduino and connect them to the +V & -V of my power supply (5v, 10A), after uploading the program all LEDs turn on and flicker in random colors:
This is my first time doing anything with resistors and I'm fairly new to Arduinos and LEDs as well so I probably missed something obvious...
The power supply does work with an Adafruit LED strip. Also I have about 20 of these LED bundles and I have tried the same configuration with 3 of them, all have the same problem
Thank you so much, I really couldn't figure it out on my own
Now that I read the link that you posted it makes total sense that this could've never worked.
Sorry, I should've tried to actually understand what I'm doing before trying to troubleshoot the specific problem that I ran into!
I guess it doesn't matter if I directly connect the GND of my power supply or the GND pin of my LEDs to my Arduino GND, but is there a preffered method?
As I so often explain here, it is important that the two wires of the power supply - 5 V and ground - travel together as a pair so that they never form an open loop which can variously radiate or pick up interference.
It is equally if not more important that the data and ground travel together as a pair. This means that the data ground must travel along with the data from the Arduino to the beginning of the LED chain.
Do you notice that there is an extra red (+5V) and white (ground) wire attached to the first LED? These are actually the connections for your power supply while the JST connector brings them together with the data line. The data and ground should travel together to the Arduino from that connector and in fact, it should also be used to bring the 5 V back to power the Arduino at the same time via the "5V" pin, all three wires together.
That is the preferred way to power the Arduino except that for the UNO, you generally should not connect the power to the "5V" pin while you have the PC connected to the USB connector. For a Nano - the better version for such projects - that does not matter.