Neopixel uneven colors

[Squimboos]

So I'm not sure here, but it seems the prizm manual could mention this on page 37. I'm just not sure about the wording. With a few colors, especially yellow, I'm pretty sure some of the LEDs are slightly off. It appears that one led is yellow, the next will be sorta green, then the next is yellow green, the next kind of orange yellow, and so on.

The way it's worded in the manual could suggest my timings are off or maybe I have the data line making a loop. I'm going to try some stuff but I'm just wondering if anyone else has seen this before?

[RarestSquirrel]

Got almost exactly the same thing on those 2 cheapo strips I bought. Resoldered everything, no fix.
It'll hit red, blue and green perfectly - but combing them to get different colours is a bit messy.

I have a sneaky suspicion its the controllers on the derpy pixels themselves, or maybe something wonky in the software?

[PCModulus]

Probably the chips, combining RGB chips to make colors can produce some idiosyncrasies.

[Squimboos]

Got almost exactly the same thing on those 2 cheapo strips I bought. Resoldered everything, no fix.
It'll hit red, blue and green perfectly - but combing them to get different colours is a bit messy.

I have a sneaky suspicion its the controllers on the derpy pixels themselves, or maybe something wonky in the software?

Hmm. So do you have other strips working fine?

[jbkuma]

You might also want to make sure your battery is fully charged, strange things can happen when the pixels are under-powered. That being said, it sounds more like a bad strip. I've personally only ever used cheap strips and never had a problem. While there are some name brands.. they are really just sourcing them from china and branding it and hopefully either providing or demanding a higher level of QC.

[Squimboos]

You might also want to make sure your battery is fully charged, strange things can happen when the pixels are under-powered. That being said, it sounds more like a bad strip. I've personally only ever used cheap strips and never had a problem. While there are some name brands.. they are really just sourcing them from china and branding it and hopefully either providing or demanding a higher level of QC.

Yea my battery was definitely fully charged. I didn't really notice it right off the bat. But then once the charm wore off a bit and I fully charged the battery, I started noticing on some colors. It's mostly on full two color schemes like complete green+red=yellow, or complete red+blue=purple. If I add some of the third color to lighten it, the colors become more accurate.

[Squimboos]

Oh and one other strange thing is during extension and retraction things get a little weird. This took me a long time to notice but take this example. If I use a complete magenta, the red will be mostly off at the end of retraction leaving the blue still going. So it's magenta at the top of the blade and right as the retraction is completing it's turned almost completely blue. It doesn't appear awful. In fact in it's own way it's kind of cool. But still, I'm wondering about it.

I still have to try some fixes, but I won't have time until later so my curiosity won't let me not ask you guys about it

[jbkuma]

Which battery are you using, and what size wiring? The blue/magenta thing does sound more like low current. Normally with RGB we'd expect things to shift toward red, but the way these things work that isn't always the case. It can also be a fidelity issue with the signal line. I've seen a lot of weird things with pixel blades and prop building over the past couple years, but nothing that exactly matches this.

[Squimboos]

Which battery are you using, and what size wiring? The blue/magenta thing does sound more like low current. Normally with RGB we'd expect things to shift toward red, but the way these things work that isn't always the case. It can also be a fidelity issue with the signal line. I've seen a lot of weird things with pixel blades and prop building over the past couple years, but nothing that exactly matches this.

I'm using the 3200 mah 10 amp from tcss. The smallest wiring I'm using is 24 gauge (20 down the line and to the battery) which is attached to the strips and board.

I'm using a 470 ohm resistor and it's a straight shot to the board as I'm still working on the chassis. So I'm not using the tcss neopixel connector yet. Is it possible I have a less than sufficient bridge on the smd pad before the LS pad? Also I'm not using the capacitor but I hadn't suspected that was the issue based on the problems described in the manual.

Thanks for reading all this stuff. I appreciate it.

[RarestSquirrel]

Hmm. So do you have other strips working fine?

Yeah, no such issue with a pair of skinny strips from adafruit.

[Squimboos]

Yeah, no such issue with a pair of skinny strips from adafruit.

Well I was going to buy some eventually anyway so ...here we go

[RarestSquirrel]

Well I was going to buy some eventually anyway so ...here we go

Good luck!

[jbkuma]

Try no resistor on the data line or a 220.

I've been building sabers and commissioned props with pixels for 2 years and I never spent more than $20/m.

[SA22C]

It's worth noting that the adafruit strips from the store are the same rando Chinese strips you can get from Aliexpress or eBay.

[jbkuma]

It's worth noting that the adafruit strips from the store are the same rando Chinese strips you can get from Aliexpress or eBay.
It even says so in their product description. Hopefully that added cost means there is better quality control, but I could but three strips even on Amazon for the price and if one is bad I'm still ahead of the game. I've purchased a lot of these strips and haven't had even one bad pixel, so it REALLY doesn't seem worth it.

[Squimboos]

It even says so in their product description. Hopefully that added cost means there is better quality control, but I could but three strips even on Amazon for the price and if one is bad I'm still ahead of the game. I've purchased a lot of these strips and haven't had even one bad pixel, so it REALLY doesn't seem worth it.


Well alright. So on the adafruit neopixel troubleshooting page it says that the power line has to be at most 1.43x the data line or at least .7x. I am using shorter strips here (currently 105 each strip). Is this why you suggested trying no resistor or a lower one? What IS the voltage of the data line on a prizm?

[RarestSquirrel]

I've been building sabers and commissioned props with pixels for 2 years and I never spent more than $20/m.

Perhaps we should start a list of known-to-not-be-crap strip sellers? Maybe I'll add it to that basics thread I'm working on.

[Tom Tilmon]

I'm awaiting 3 meters from aliexpress. So, we'll see there. Hopefully we're good.

Tom

[jbkuma]

Well alright. So on the adafruit neopixel troubleshooting page it says that the power line has to be at most 1.43x the data line or at least .7x. I am using shorter strips here (currently 105 each strip). Is this why you suggested trying no resistor or a lower one? What IS the voltage of the data line on a prizm?

I've been building pixel blades with Arduino boards for the past two years, at first one didn't is resistors at all. It sounds like you could be having signal integrity issues and it's easy and cheap to find out. Could be a cold joint or bad wire. I was breadboarding a project today and had similar issues until I just soldered it up instead.

[Squimboos]

I've been building pixel blades with Arduino boards for the past two years, at first one didn't is resistors at all. It sounds like you could be having signal integrity issues and it's easy and cheap to find out. Could be a cold joint or bad wire. I was breadboarding a project today and had similar issues until I just soldered it up instead.

I think I found the issue actually. I think when I originally stripped the data wire, I might have pulled a couple of strands short. My son accidentally yanked it and bam.. 3 almost too small to see strands of wire were poking out near the solder joint. So yea. Bad tinning, bad solder joint. Bad all around. Gonna redo that and hopefully all will be fixed.

[jbkuma]

I bet that will fix it. Let us know how it works out!

[Tom Tilmon]

jbkuma,

I ordered 5050 strips from china. The colors are all messed up. The strips had some defects from manufacturing, mainly solder joint issues at joints. I fixed all those issues, and got the strips working, but the colors are all amok. Green, Red, Blue apparently. I feel I wasted money and time on these things. I'm pretty frustrated with them. Going back to the adafruit skinnies.

Tom

[jbkuma]

I've literally gotten dozens of strips from random vendors without issue, sorry to hear you are having issues. Adafruit orders their strips from China and reselling. They aren't making them, they are very clear that they can't even promise if you are getting WS2812 or SK6812.

I hope your new strips work out.