Color issues on multiple psu- basic test

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qtong

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Hi have the ws2811 strips hooked up as so: PSU1- strips 1-11, PSU2- strips 11-20, PSU3- strips 21-32 with 2 teensys, each controlling half. I am running basic test to check for flickering and found that the colors are going through the strips well until it hits the other next psu. The strips are a different color than the other and there is flickering. I have the teensy grounded to both the psu's powering the set of strips along with the 220ohm resistors close to teensys.

Is my wiring incorrect? Also, what type of wire should be used for signal? I am using 18awg for 5v and grnd wires, 22awg for signal.



Thanks
 
A few questions for you:
How many LEDs per strip?
how long is the wire between the teensys and the strips?
have you tried a lower resistor value (~100 ohm)?
are you running a GND from each strip back to the corresponding teensy?
 
tetsuo said:
A few questions for you:
How many LEDs per strip?
how long is the wire between the teensys and the strips?
have you tried a lower resistor value (~100 ohm)?
are you running a GND from each strip back to the corresponding teensy?
Click to expand...

I have 120 leds per strip, powered and grounded from both ends.

I recently shortened the length from 3-4 feet to about 5" - 18"

Have not tried a lower resistor value, based on what I read, 22awg signal wire works best with the 220 ohm resistors and that the 100ohm resistors are good for twisted pair/CAT wires?

The 5v and gnd on both ends of the LEDs are connected to the psu. The teensy has 2 gnd wires, each running to the 2 psu's that are powering the leds.

Thanks for the response!
 
It really sounds like a grounding issue. Try running an additional GND from one end of each strip back to the teensy GND. Also, how does your voltage look in the middle of the strip? Paul suggests aiming for no less than 4.8V at the lowest voltage along the strip, but I've gotten things working cleanly as long as voltage is >= 4.5V and DIN voltage is within 1V of that value.

I found that 220 ohm was too high for both the 18 awg (in-wall rated/twisted) speaker wire I tested, as well as for CAT6 cable... however, my cable runs are up to 18 feet.
 
Tetsuo,

It was definitely a grounding issue! I did as you said and it works! Another issue was that some of the connections on the led strips were bad, I had to cut the first led out and solder in a different one and that cleared up some of the issues as well. Thanks for your help! (I'm sure I'll be lost again soon enough!)
 
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