These are chat archives for Makuna/NeoPixelBus

2nd
Jun 2018
Mitchell Ton
@BrainCoder
Jun 02 2018 13:02 UTC
Is anyone else experiencing brightness shifting followed by color shifting after around 320 leds?
on ESP8266 DMA
Michael Miller
@Makuna
Jun 02 2018 17:40 UTC
@BrainCoder How are you connecting power to that many pixels? Each RGB pixel should be provided with at least 40ma (60ma at full brightness); and the wires between them often is not big enough to power more than 100, so you have to inject power along the strip or at least from both ends.
Mitchell Ton
@BrainCoder
Jun 02 2018 18:07 UTC
@Makuna currently I inject power every 50 pixels and the voltage never drops below 4.5V at any point
it looks like a timing issue because it switches from dim red to full red to full green
Michael Miller
@Makuna
Jun 02 2018 18:10 UTC
Is this a flexible strip or matrix (or other board mounted pixels)?
Is the color change near a power injection point?
Have you placed capacitors on the power? (see link in my readme/wiki about powering)
Mitchell Ton
@BrainCoder
Jun 02 2018 18:11 UTC
its 5 non flexible matrices combined
the color change happens half way down a matrix but not if connect the data straight to that matrix (leaving the power connected the same)
Michael Miller
@Makuna
Jun 02 2018 18:12 UTC
Do you have a link to the matrices (just so I can look up rather than ask a bunch of questions)?
If you switch the "order" of the matrices, does it still happen at the same point?
Mitchell Ton
@BrainCoder
Jun 02 2018 18:14 UTC
I don't think its a issue with the library. Since they are self made matrices
it happens after 320 to 340 ish leds
order of the matrices does not matter
Michael Miller
@Makuna
Jun 02 2018 18:15 UTC
Does it happen on every Show() or just once in a while?
Mitchell Ton
@BrainCoder
Jun 02 2018 18:16 UTC
90+% of the time
but sometimes its not
Michael Miller
@Makuna
Jun 02 2018 18:16 UTC
And what esp8266 are you using, what Arduino IDE, what Esp8277 board support version, and what speed are you running your esp8266 at ? I will put it on a logic analyzer and confirm latter tonight.
Mitchell Ton
@BrainCoder
Jun 02 2018 18:17 UTC
wemos D1 mini
Michael Miller
@Makuna
Jun 02 2018 18:17 UTC
Read the link I mentioned about powering NeoPixels, have caps and resistors (if not already present on the board) as these can cause the effects you are talking about.
Mitchell Ton
@BrainCoder
Jun 02 2018 18:21 UTC
I will i am pretty sure the capacitance should be enough maybe a bit overkill
I have separate 1206 100NF per pixel and an extra 1000uf per panel
but i will connect a logic analyzer later today and send you a copy
Michael Miller
@Makuna
Jun 02 2018 18:38 UTC
I have a D1 mini so I will use that for tests. Make sure to include versions of stuff as I mentioned above; so I can compare appropriately. I tend to use only the latest released, no betas, no prereleases, no older versions.