Trinket M0 and SMD 2812 LEDs Power issue

[wsmeador]

I've got a strip of 75 LEDs wired to a Trinket M0 running Circuit Python. It's wired USB, Gnd, and pin 4. Connected to a computer it works like a champ - updating code and running for long periods of time it works great. Attached to a USB charger, the lights do not behave correctly. They will slowly pulse and change color. The brightness is correct. It kind of resembles what it's supposed to do, but definitely not correct. Doesn't matter what computer it's plugged into, it works great. Trying USB chargers (various amperages), smart chargers, and a USB 2 hub yields the strange behavior.

The strip was cut from https://www.amazon.com/gp/product/B078X ... UTF8&psc=1

Is the computer adjusting the power load in a way that a charger can't? I haven't tried powering the LEDs separately. I wonder if the data pins from the computer are helping things out timing-wise?

Best,

Scott
Scott

[Franklin97355]

Your powerbank is probably not providing as much power as the computer can.

[wsmeador]

I purchased a USB tester and found that when plugged into a computer the project is rock steady at 5.09V and .27A. When plugged into a smartphone charge it flashes trying to run the program from 5.03V to 3.55V and .27A to 1.3A. With a smart charger it was a little more steady at 4.95V and 2.75A, but not running the right program.

[XRAD]

different USB builds also have various bandwidth, V max, and amperage. Read about USB 1, 2, and 3.x for more info. Powered add on USB port extenders can offer a full 5a and more.

[wsmeador]

More info. A moment ago I plugged another Trinket M0 (that was wired to the same LED project before I replaced it with a backup) to a strip of the same type of LED strip and into one of my USB chargers. Steady with the same V and A readings as a computer.

The difference is that the project has breaks in the LED strip with soldered jumper wires. It was split into three strips to create a series of rings rather than a continuous spiral.

Is it possible that the soldered jumper wires are causing a problem? It's just so strange that it is fine with a computer (any computer and regardless of USB 2 or 3), but wildly wrong using a USB charger, but with the same equipment and code, but no breaks in the strips, it works great with the same chargers.