14x14 matrix
ws2812B.
teensy 3.1
XYMatrix example code
So, at the time I am powering the teensy via usb, and have a proto board its on that then powers my LEDs. I have power input at start and end of the matrix.
When Im plugging into my laptop, the code runs fine.
However, when I use any other usb supply, It goes for a few seconds then pitches down brightness and all red. Obvious a power issue of some sort. (my voltage meter is also MIA which is not helping)
But Im lost right now how my weak usb ports (im guessing 500mah or 1A max) on my laptop can keep it going while my 1A, 2.1A and 3A supplies dont seem to do it. My big 20A one does though.
I shouldnt power it all via usb, but ive had other project work ok this way.
What laptop? Some laptops will freely give more than 500mA - while many USB power supplies will only give 500mA unless you have the magic combination of resistors to unlock higher amperage charging.
Many USB supplies are picky about how many amps they will really give you. You may not be pulling 3A for your project, but you’re probably pulling more than 500mA but all the USB power supplies aren’t trusting you with more than 500 (or in some cases, only 100mA)
I don’t know the details (mostly because I don’t power many projects off USB chargers anymore) - but there’s games with resistors on pins to basically negotiate with the power supply over how much current you wa t.
@Nail_ENVY that would probably work too. In the end I’ll have an 8A supply for the whole table and not power it through the USB of the teensy. Still working on ways to make the components and cables are compact and hidden as possible. just found it odd my laptop/table could power it and the other supploes dropped. I decreaded the max brightness from 64 to 50 and the 3A wallplug works. but final version i want brighter to go through the white acrylic draft sheet top.
You should really try to measure what your actual draw is. I’d put money on your 3A wall plug not actually giving you 3A, or at least not sustaining it.
@Nail_ENVY ive been using teensy for my strips without issues for so long, i hadnt even really thought about that impact actually. its just always worked.