NeoPixel strip are flashing after "white" led

Hello everybody, I have problem with Led RGB neopixel strip (WS2812B chip). I'm using 45 leds and I'm controlling it by Arduino Nano. Power supply is USB charger 5V/3A ( 45 x 60mA = 2,7A ). Led strip and Arduino have same ground from USB charger. If I use any arduino script (lib: FastLED, or NeoPixel) for animation on script, 'all' working good. Good is all single color and low brightness color. If is high brightness or white color (255, 255, 255) all strip flashing with random color in random pattern.

I try study and testing it and I find out: I testing only 3 diods. Differend color on all diods work good, but if I set (255, 255, 255) on first diod -> first was white and second and thirs are random flashing ..... If I set on first diod only one color (255, 0, 0) or low grightness color (32, 54, 10) and on second diod I set white color -> first and second diods was good, and third diod flashing (sometimes flashing with correct color, sometime random color). If I using for supply 3 diods only Arduino (without USB charger) all work good. But all strip can't supply by arduino.

My knowledge is: all diods after one high brightness are flashing. And I think, It look as bad grounding, but I don't know why because I have connected same ground to strip and arduino.

If somebody can help me I will very happy. Thanks

try with only 5 led working at a time and see what happens.

Maybe important info: I made "own" strip from single adressable leds (WS2812B on pcb) because I need specific distance between leds.

I try connect really only 5 leds (not all strip but using only first 5 leds) and with single arduino is all good, with external supply is too all good, not flashing

But if I connect 15 leds to strip it start same flashing - after "white" color led

New knowledge is if I declare in script 10 leds in strip (really I have connected 45 leds) flashing after white led is slowly, but if I declare 45 leds, flashing is faster .. It look as problem with communication whit long strip, but it is nonlogic, because arduino only giving logical data output (output is same as (0,100,0) and (255, 255, 255) in data delivery can't be problem, because all 45 leds work perfectly and fast with demo example )

For enough of power I use 2200uF cappacitor. ( if connected all dissabled strip cap is discharged very fast, If connected only 5 enabled (lighting)leds discharged is slow ---> Why do not lighting leds use power? Isn't probleme here?

How long are the strips? How are the LED's wired together? How large (in amps) is the power supply you are using? 45 RGB LED's with all components at max brightness consume (45pc * 20mA * 3comp) 2700mA @ 5V.

Danois90: How long are the strips? How are the LED's wired together? How large (in amps) is the power supply you are using? 45 RGB LED's with all components at max brightness consume (45pc * 20mA * 3comp) 2700mA @ 5V.

My strip have 45 leds and about 140 cm. I wired (soldering) with old PATA cable (PATA cable which used for connected old HDD) in diameter it has 0,4 mm ... I know, it is not the best type of cable for transfer 2700mA but I think it not bad for using for this project.

I use as power supply USB charger with 3A / 5V (it's original for RPi)

I think, I have enough of power, because if all strip can flashing with one full color (for example (0, 0, 255) ) all current is 45 * 20mA = 900mA and it work correctly .... but if I use only one white color, is problem ... one white pixel have 60mA it's lower than 900mA what work fine

The wires are quite thin, but they should be able to handle the current. I have soldered a couple of SMD SK6812 into "special patterns" and doing that I found out that the LED's are quite easy to overheat / damage. Also I found out that if there is a bad connection (data in/out, cold solder joint), some LED's may produce erratic colors or even flicker.

I think you should check all your LED's one by one and see if they work as expected using the wires you have soldered onto them. It does not matter if they are interconnected during the test, just make sure that your sketch only assumes one LED.

EDIT: Oh, and make sure to disconnect power when moving the data signal!

Danois90: The wires are quite thin, but they should be able to handle the current. I have soldered a couple of SMD SK6812 into "special patterns" and doing that I found out that the LED's are quite easy to overheat / damage. Also I found out that if there is a bad connection (data in/out, cold solder joint), some LED's may produce erratic colors or even flicker.

I think you should check all your LED's one by one and see if they work as expected using the wires you have soldered onto them. It does not matter if they are interconnected during the test, just make sure that your sketch only assumes one LED.

EDIT: Oh, and make sure to disconnect power when moving the data signal!

Thank you so much, I will try it. At now I always have connect power and upload new sketch.

If I catch it, I look on all data in/out joints if are good joints and then testing all single led one by one .. must I every time resolder data pin on each single led? Or have sketch with 45 leds and lighting one by one led? (All leds are good, because I can controll all leds, It work if I upload sketch which do on strip moving rainbow or a few pixels in row moving side to side )

Overheat is good point, If my wire will heating I'm will solving it, But at now isn't problem high current

I was check all Led's joint and tested all led one by one. But all work perfectly, single led work good, but all strip don't.

Measure the supply voltage (not the voltage on the data line) on each individual led.

I suspect that you can't use that PATA cable for power and ground (too thin).

sterretje: I suspect that you can't use that PATA cable for power and ground (too thin).

May be a problem but I've used 0.14mm2 wires to solder SMD SK6812's together and the thin wires cased me no problems. The length of my wires where somewhat shorter, however (~1.2M 5 LED's).

Voltage are on every led same 5,2V.

I think is no problem with thin wire, maybe can be problem with heating in high current, but I do not know it I'm happy for every ideas.

Same strip, if I supply it by arduino it worked good, if external supply is problem.

Maybe I will use other wire, but it is again a lot of soldering :D