Checking wiring connections for lights

BundyRoy

Dedicated elf
Joined
Apr 9, 2014
Messages
1,026
I was putting some lights together tonight and when I was putting the heatshrink on I was think about ways of checking which pigtail pin was hooked up to +ve/-ve/data (ws2811 pixels) in the future as I wouldn't be able to see the soldered connections. So I thought I would check the wire resistance between pins at each end of the string to see what it told me. This is what I got.

+ve in to +ve out - very little resistance (ie direct connection)
+ve in to -ve out - higher resistance
+ve in to data out - no connection

-ve in to -ve out - low resistance
-ve in to +ve out - higher resistance
-ve in to data out - no connection

data in to -ve out - higher resistance
data in to +ve out - higher resistance
data in to data out - no connection

I've tested the lights and they work. I have not tested if a string connected downstream works yet as I haven't got another string with connectors on it yet.

What this tells me is I can isolate the data pin from the +ve/-ve pins but I can't tell which one of the other two is +ve and -ve by using resistance measurements.

If you forget the pin location is there a way of determining the +ve and -ve pigtail pins without cutting the heatshrink off and looking.

I hope this makes sense and I hope the measurements I've taken are right. I've double checked but I could be going number blind.
 

David_AVD

Grandpa Elf
Community project designer
Generous elf
Joined
Jun 12, 2010
Messages
4,681
Location
Victoria Point (Brisbane)
It's not really possible to tell V+ from V- in a situation like that. Your best bet is to choose a pinout, document it and stick to it.
 

BundyRoy

Dedicated elf
Joined
Apr 9, 2014
Messages
1,026
Thanks David. I figured that might be the case.
 

BundyRoy

Dedicated elf
Joined
Apr 9, 2014
Messages
1,026
Not that it really matters but I just noticed that there is a dodgy connection in the second last node of the string I was testing last night. Sometimes the last two pixels work sometimes they don't, depends on how you hold the wires. So the resistance measurements below may be influenced by that as well. I think it explains why I thought I was going crazy last night. I could of swore I measured the same two wires multiple times for different results. Looks like I probably did due to the faulty connection.
 

scamper

Dedicated elf
Joined
Jan 5, 2014
Messages
1,225
Location
collie
I agree, come up with a wiring standard for your lights.
I chose what I thought to be logical, wired one up, took a photo and printed it out and then stuck it on my wall where I do all my wiring.
After about the 100th time, you tend to start remembering :)
 

BundyRoy

Dedicated elf
Joined
Apr 9, 2014
Messages
1,026
Thanks Scamper/David. I do have a wiring pin out that I use and as you say it is easy to remember after a bit of repetition. My hassle is I have bought some second hand lights and the pin out is different to mine. Don't really want to change the lot but I can see having two systems will cause problems somewhere down the track. Was wondering if there was an easy way to check which pin was what.


My other issue is some of the lights I bought are in plastic balls (opaque) so I can't actually see the pixel to determine which wire is which (all wires are black on string). Haven't had a hard look at the lights yet so am hoping the balls can be opened up without being destroyed.
 

David_AVD

Grandpa Elf
Community project designer
Generous elf
Joined
Jun 12, 2010
Messages
4,681
Location
Victoria Point (Brisbane)
Changing the other connector pinouts may be a pain, but hooking them up to the wrong system and blowing them is worse.
 

BundyRoy

Dedicated elf
Joined
Apr 9, 2014
Messages
1,026
Thanks David, you're confirming the thoughts I already had. Was just living in denial for as long as I could. The good news is it's a while to go before Christmas so there is time.
 

the grinch

I guess I could use a little social interaction
Joined
Jun 23, 2013
Messages
464
Location
angle vale s.a.
Not sure if I can help here or make sense but yes I try to keep it simple and yes absolutely do all work the same and do not cover up my work in a fashion that cant see what ive done heatshrink each wire individual then clear shrink on top so can see whats been done if needed .for dumb rgb pigtail connection
Red to red some tails have brown wich to me is red
Blue to blue
Green to green
Then black or white to black or white silly but is positive connection but works for me
Must always check the rgb order as is different for different brands of lighting and batches .have found even as light or strip clearly marked + r g b wrong dont trust test first .
Smart pixels
Red to red or brown. positive power +
Black or white to black or white . For negative power -
Blue to blue
Green to green
Depending on types of pixels 3 or 4 wires
Clock and data wires found mixed up frequently also worth checking
I try to keep things as simple as possible and also if please no! But if trouble easier to fault find
Goodluck hope can help
 
Top