Christmas LED Lights...Hows that work then?????

[chris_k]

Just put up some Christmas lights that the wife bought from Matalan. Standard thing. Plug in wall transformer with onboard  button to select program. The lights are led and have 2 strings. Programs are various flash, sequence, fade and static.

Got the lights up and went to plug the light string into transformer and noticed its a standard 5.5mm dc power jack.

How does the light string manage to do various patterns with just 2 cables. Im thinking certain leds are reverse polarity and the transformer does the switching to turn them on alternately? If so how does it light all the lights at the same time?

ta muchly

 

[Blue Duck]

The transformer swaps the polarity to make the leds (RGB) animate which is programmed in sequences make pretty colours and effects.

A more complicated example would be an LED tv.

Guinness

 

[chris_k]

The leds are warm white and the cable is 2 core. if it reverses polarity to get set "b" on then reverts to normal polarity to get set "a" on. how does it get them on at the same time?

 

[Lurch]

Programmable LED's.

https://learn.adafruit.com/adafruit-neopixel-uberguide

Something along those lines. Permanent DC supply with a control signal superimposed on the same 2 wires.

 

[steptoe]

Fairly old technology really,

A common household use for it in the 80s was in model railways.

 

[SPECIAL LOCATION]

Fairly old technology really,

A common household use for it in the 80s was in model railways.

I was just about to suggest is it anything similar to the old Hornby Zero1 controller...

stick a little receiver chip thingy in your train...

Select the code at the controller and operate multiple trains at the same time over the same two 12v rails (two wires)..

So it can't be that difficult to reduce something down to a smaller scale to just turn on/off a few LED's or dim them over a sequence...

(bit like train going faster or slower..  ON/OFF/DIM)

still got my old Hornby trains in the loft...

May even still have a Zero1 controller....  (or I may have chucked it cant remember)

Think I started converting back to traditional 12v bog standard controller after a few glitches and hiccups with the multi-train controller.

But hasn't been out of the loft for a long time now.

opcorn

 

[Lurch]

A common household use for it in the 80s was in model railways.

Hornby Zero1, I've got a couple of sets floating about somewhere. It has evolved into what is now DCC which is a more complex 2 wire control system. ZTC have some controllers which are DCC & Zero1 compatible, for some reason.

 

[Lurch]

Think I started converting back to traditional 12v bog standard controller after a few glitches and hiccups with the multi-train controller.

The Zero1 wasn't the most reliable system, I have thought about making a retro layout with the Zero1 but then I think why bother, there is a reason it isn't made any more!

 

[SPECIAL LOCATION]

The Zero1 wasn't the most reliable system, I have thought about making a retro layout with the Zero1 but then I think why bother, there is a reason it isn't made any more!

It was a radical step forward when it came out.......

But a bit to fast and ahead of its time, without proper testing & debugging!

They do something nowadays with Scalextric cars swapping and sharing the same track.....

Is that a variation on a theme?

opcorn  

 

[steptoe]

Exactly what I was pointing at,

Yep, I have a zero1 in my mums loft, I couldnt get it sorted either, but, I was a lot younger and less patient then .

 

[Lurch]

But a bit to fast and ahead of its time, without proper testing & debugging!

I dunno, when you read the technical documents it is quite complex and detailed. The unreliability is more down to external interference, which is often mostly down to contacts between dirty track and loco wheels.

They do something nowadays with Scalextric cars swapping and sharing the same track.....

Is that a variation on a theme?

Pretty much exactly the same thing.

 

[chris_k]

Every day`s a learning day!

Ta Muchly

 

[Richard-the-Ninth]

Think you will find they do reverse the polarity, and to have both strings on they pulse it. The only chip is at the controller.

You can get a string of RGB LEDs that have 3 wires, each LED on the string can be any colour you like and you can set them up to change colour in sequence, these do have a chip in each LED. They are known as LED Pixels

I found a clip of some working.

https://www.youtube.com/embed/r0IE2d8eeWg?feature=oembed