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Preventing reversed polarity

sspenning · 150

sspenning

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on: February 12, 2019, 08:36:20 PM
The backstory:
So this last Sunday I was rushing to complete my first Moodlite build as a surprise gift for my wife this Valentines day (Feb 14 for those who don't observe).  I was testing each strip of 3 lights  I completed by plugging it into my first reference strip and the programmed NodeMCU controller.  While testing what would be the last string for the day, I accidentally flipped the servo cable end while plugging it into my reference strip.  A whiff of acrid blue smoke later, I'm down two completed strands of lights and a NodeMCU.

Apart from the obvious "don't flip the poles", does anyone have any recommendations for preventing this in the future?

For the moment I've gone through all of my servo extension cables and painted the ground side to make sure that they line up in the future but I'm concerned it will wear off with use.  Additionally I'm looking at building my own cables with latching polarized connectors like this http://www.hansenhobbies.com/products/connectors/pt1inlpconnectors/pt1in_lp_1x3/.

I'm curious if anyone else has better solutions.



shfaxx

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Reply #1 on: February 13, 2019, 01:05:34 AM
Wow I did this last week on my last panel, but nothing happened.  The panel simply didnít light up.  I flipped the cable and all was good.  Guess I got lucky.



NotionalLabs

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Reply #2 on: February 14, 2019, 08:43:41 AM
Sspenning - It looks like your LED strip might use WS2812's instead of the newer WS2812b's - they added reverse polarity protection in the newer model: https://cdn.sparkfun.com/assets/learn_tutorials/1/0/5/WS2812B_VS_WS2812.pdf

I've almost plugged mine in the wrong way a bunch of times too - i think having a polarised latching connector is a great idea, but it might require some modifications to the print model to fit.



sspenning

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Reply #3 on: February 14, 2019, 04:55:20 PM
That is great information!  Thanks!

I hadn't realized that the "B" variant had protection built in.  The strips I purchased were supposed to be WS2812B so I guess I got screwed there.  I'll switch vendors next time to see if I have better luck.



shfaxx

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Reply #4 on: February 15, 2019, 01:28:39 AM
Sspenning - It looks like your LED strip might use WS2812's instead of the newer WS2812b's - they added reverse polarity protection in the newer model: https://cdn.sparkfun.com/assets/learn_tutorials/1/0/5/WS2812B_VS_WS2812.pdf

I've almost plugged mine in the wrong way a bunch of times too - i think having a polarised latching connector is a great idea, but it might require some modifications to the print model to fit.

Well there ya go....   That's why I didn't have a problem.  def good to know, thanks!



 


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