Shopping List

[DougieB]

So finally starting to put together my wish list/shopping list to build my new display after a 10year absence and have a couple of questions for the learned people on ACL

• How do people find the seed/pebble pixels. are they as bright/reliable/workable as the bullets or strips?
• Is having a dual data line a good idea or a nice to have, ie WS2818
• Should I go PI or Beagle

That will do for now, still researching and relearning and basically catching up
Thanks in advance for any responses
Doug

 

[Mark_M]

So finally starting to put together my wish list/shopping list to build my new display after a 10year absence and have a couple of questions for the learned people on ACL

• How do people find the seed/pebble pixels. are they as bright/reliable/workable as the bullets or strips?
• Is having a dual data line a good idea or a nice to have, ie WS2818
• Should I go PI or Beegle

Seed pixels are bright and cheap, not going to last as long as bullet pixels. Pebble pixels are a bigger, heaver but more robust pixel.
Pebble pixels are different to seed pixels, it's deceiving calling them the same!

Dual data line 'backup data' pixels is great to have IF you want to spend the extra money on them.

Beagle (with a cape, e.g. a Kulp controller cape) tends to do more pixels than a Pi with a hat (e.g. the Falcon Pi hat).

 

[Grozzy]

One other important question that I'm asking myself after a bad experience with pixel failures two years in a row.

Am I willing to tip a few thousand dollars on pixels in 2024, has the quality improved and who do I buy from?

 

[Johnnyboy]

So finally starting to put together my wish list/shopping list to build my new display after a 10year absence and have a couple of questions for the learned people on ACL

• How do people find the seed/pebble pixels. are they as bright/reliable/workable as the bullets or strips?
• Is having a dual data line a good idea or a nice to have, ie WS2818
• Should I go PI or Beagle

That will do for now, still researching and relearning and basically catching up
Thanks in advance for any responses
Doug

I've ordered just over 18k seed pixels this year with dual data wiring, but i am getting them wired up to standard 3 pin connectors rather than 4 pin. There is some small downsides, in that if you get a failure between the first and second pixel it will take out the full string. However, if you get a failure from pixel two to the end of the string the dual data line will still work. Of course, if you have a faulty extension cable etc from the controller that will take out the sting as well. You can do this either in custom strings or use adapters, I went the custom seed pixel string route. The 4-3 pin adapters are quite pricy so it adds up quick.

For the Pi vs Beagle debate. Last year I ran a 14k show off a Beagle Bone Green that worked great. The Beagles are capable of running may more pixels than that. In saying that, this year I am switching to a Pi due to needing to repurpose the BBG in Kulp controller. Had I not purchased the Kulp, i would still use the BBG this year. If I was starting fresh, I would go the Pi route. Mostly because that's what most people use, and you will have more support.

One other important question that I'm asking myself after a bad experience with pixel failures two years in a row.

Am I willing to tip a few thousand dollars on pixels in 2024, has the quality improved and who do I buy from?

2023 was my first year and i purchased just over 14k pixels from LightitupLED's and didn't have a single failure. One pixel on my mega tree strand did go out and i squeezed it and it came back to life. I will cut out and replace it for the 2024 season, but never had further issues with it in 2023.

I don't think my experience is unique for 2023 with most venders having a really good year for failures, nothing like 2022. Any of the Aussie vendors/resellers is a safe bet as they support the hobby quite well. Not sure when you purchased pixels and was very thankful i had a good season.

 

[Skymaster]

There is some small downsides, in that if you get a failure between the first and second pixel it will take out the full string.

This should not happen.
The second pixel receives the initial data line (which bypasses pixel 1) as its backupinout, whereby it looks at pixel n+1 data rather than the standard pixel n of the primary line.

They only way you'll lose the remainder of a string is losing data between the controller and the first pixel, and anywhere you go back to 3 wires from 4 if you use 3 wire pigtails between strings.
The other circumstance is two consecutive pixel failures.

 

[Johnnyboy]

This should not happen.
The second pixel receives the initial data line (which bypasses pixel 1) as its backupinout, whereby it looks at pixel n+1 data rather than the standard pixel n of the primary line.

They only way you'll lose the remainder of a string is losing data between the controller and the first pixel, and anywhere you go back to 3 wires from 4 if you use 3 wire pigtails between strings.
The other circumstance is two consecutive pixel failures.

perhaps i misunderstood the potential pit falls when i they were explained to me a while ago. I confess i'm very much a novice on how the dual data lines work. Based on your response, it seems it's even better than i thought for performance/redundancy the start of a string.

I wasn't aware that any consecutive failures would also take out the string as well. Good to know. Will also be something i keep in the back of my mind if i ever get a failure mid way through a string. replace 2 pixels at a minimum!

Cheers

 

[merryoncherry]

perhaps i misunderstood the potential pit falls when i they were explained to me a while ago. I confess i'm very much a novice on how the dual data lines work. Based on your response, it seems it's even better than i thought for performance/redundancy the start of a string.

You're not the only one who seems confused. The vendor that sold me mine didn't understand either, and even wired some of the 3->4 adapters wrong, which I had to field-fix by hacking up the adapters.

But it really isn't hard at all. The input data line for pixel 1 is passively wired to the backup data line for pixel 2, and so on. Each pixel will, if it doesn't think it is getting good signal from the primary data line, read the backup line and skip the first pixel of data from it (because it is the same signal that was intended for the pixel in front of it). So, if pixel 2 is not getting data from pixel 1 it will fall back to its backup data line, which is passively wired (within pixel 1) to be the same as what came from the controller. It skips pixel 1 data and proceeds.


Like Sky said, this covers failures where the pixel chip dies, as long as it isn't two in a row. It won't cover physical breaks in the power, ground, both data, that sort of thing.

But the other thing that has people confused is that because they think pixel 1 is special (just explained why it is not) you ought to do something to the controller to compensate for this. But, if the controller dies, you're hosed. If the cable from the controller is broken, you're hosed. There is nothing terribly interesting that you can do to the controller to drive 4-wire pixels better... you could send backup data but this would take a lot of work (to introduce an additional pixel into it for pixel 1 to skip if it falls back to its backup data line) and the only failure it would cover is a physical break in the data line that did not affect power and ground.

 

[Skymaster]

Thanks MOC. You saved me the effort of drawing that up once the kids were in bed my phone skills do not extend to graphic art

 

[DougieB]

I've ordered just over 18k seed pixels this year with dual data wiring, but i am getting them wired up to standard 3 pin connectors rather than 4 pin. There is some small downsides, in that if you get a failure between the first and second pixel it will take out the full string. However, if you get a failure from pixel two to the end of the string the dual data line will still work. Of course, if you have a faulty extension cable etc from the controller that will take out the sting as well. You can do this either in custom strings or use adapters, I went the custom seed pixel string route. The 4-3 pin adapters are quite pricy so it adds up quick.

For the Pi vs Beagle debate. Last year I ran a 14k show off a Beagle Bone Green that worked great. The Beagles are capable of running may more pixels than that. In saying that, this year I am switching to a Pi due to needing to repurpose the BBG in Kulp controller. Had I not purchased the Kulp, i would still use the BBG this year. If I was starting fresh, I would go the Pi route. Mostly because that's what most people use, and you will have more support.


2023 was my first year and i purchased just over 14k pixels from LightitupLED's and didn't have a single failure. One pixel on my mega tree strand did go out and i squeezed it and it came back to life. I will cut out and replace it for the 2024 season, but never had further issues with it in 2023.

I don't think my experience is unique for 2023 with most venders having a really good year for failures, nothing like 2022. Any of the Aussie vendors/resellers is a safe bet as they support the hobby quite well. Not sure when you purchased pixels and was very thankful i had a good season.

Thanks Johnny
for your seed order, did you go 12v or 5v

 

[DougieB]

You're not the only one who seems confused. The vendor that sold me mine didn't understand either, and even wired some of the 3->4 adapters wrong, which I had to field-fix by hacking up the adapters.

But it really isn't hard at all. The input data line for pixel 1 is passively wired to the backup data line for pixel 2, and so on. Each pixel will, if it doesn't think it is getting good signal from the primary data line, read the backup line and skip the first pixel of data from it (because it is the same signal that was intended for the pixel in front of it). So, if pixel 2 is not getting data from pixel 1 it will fall back to its backup data line, which is passively wired (within pixel 1) to be the same as what came from the controller. It skips pixel 1 data and proceeds.

View attachment 25663
Like Sky said, this covers failures where the pixel chip dies, as long as it isn't two in a row. It won't cover physical breaks in the power, ground, both data, that sort of thing.

But the other thing that has people confused is that because they think pixel 1 is special (just explained why it is not) you ought to do something to the controller to compensate for this. But, if the controller dies, you're hosed. If the cable from the controller is broken, you're hosed. There is nothing terribly interesting that you can do to the controller to drive 4-wire pixels better... you could send backup data but this would take a lot of work (to introduce an additional pixel into it for pixel 1 to skip if it falls back to its backup data line) and the only failure it would cover is a physical break in the data line that did not affect power and ground.

Awesome, thanks for the clear explanation

 

[Mark_M]

Thanks Johnny
for your seed order, did you go 12v or 5v

Other person's opinion;
I use 5v for my mega tree. It would have been awesome if 12v existed when I bought those seed pixels!
5v is fine if you're willing to power inject every ~50 pixel nodes.

 

[DougieB]

Thanks Mark
I was leaning towards 12v for that reason. decision made

 

[Johnnyboy]

Thanks Johnny
for your seed order, did you go 12v or 5v

12v

Thanks Mark
I was leaning towards 12v for that reason. decision made

12v for reduced power injection as Mark mentioned, but also because the rest of my display is 12v and I don't really want to deal with multiple voltages.

Next question you need to decide on is seed spacing! lots of debate on that front. I've gone with mostly 3cm (super close) but also a bunch of 10cm. The 3cm stuff will be realllllllly tricky to solder/join/repair. To combat that i've bought a bunch of spare strings to replace the whole string rather than repair on the fly.

 

[Skymaster]

A good trick is if you need long runs of close spacing - go double the distance and fold it on itself.
So instead of 2.5cm, get 5cm and fold it back. Makes termination a heck of alot easier with the extra wire.
That said, it really depends on where you intend to run it.

I am planning on using that method this year to double the vertical density of my solar matrix.

 

[Mark_M]

A good trick is if you need long runs of close spacing - go double the distance and fold it on itself.
So instead of 2.5cm, get 5cm and fold it back. Makes termination a heck of alot easier with the extra wire.

Best advice when using seed pixels!
They're a pain to splice at 5cm, let alone any smaller.

Alternate nodes is literally folding the string in half, so every gap between a pixel is filled by another.
IMO it helps for power injection because you can effectively power from both ends of the string from one side.