We usually put up some Christmas lights on the house - some fairy lights on the metal fencing at the front, but a pain as means a cable out of a window. They are usually just normal fairy lights.
But with my new found expertise in WS2812 style LED strips, and my controllers, I decided to do better.
11m of wooden fence at the front of the house on the road. So let's do this properly. The key point is I have outside power at the end of the fence for the hot tub. So I was able to install, under cover, a 20A 5V power supply.
I then got 4 strings of fairy light style water proof 5V WS2812 LEDs.
I drilled nearly 200 holes, carefully measuring each to be level and evenly spaced. That is surprisingly hard work, LOL. James followed me poking LEDs through the holes. We were both expecting to fall off the damn wall, and James's main concern is I would fall off whilst he was not videoing!
But it is not quite so simple. Just in case you don't know, there are two common issues with LED strips.
Current limit
One issue is max current draw can be too much for power supply. To test you can either work it out, or, simply set all LEDs full white. 200 LEDs is too much for a typical small 5V USB charger plug. Hence the 20A 5V supply.
I actually also did 663 (11m) RGBW LEDs on nice 45 degree extruded trunking with diffusers for the hot tub as well, from same supply. Now that used a lot of current - just one 5m strip is too much for a USB 5V charger when white.
Voltage drop
This is slightly harder to solve. Along the strip the current draw means voltage drops as you go along. Different LEDs need different voltages. First you lose some blue making it yellow, and then some green, making red/pink. And even before that, when white still, you lose some brightness.
So with this 50 LED strip - one strip works. Two strips work but losing brightness at end. Three strips means going distinctly yellow at the end. I wanted four strips!
The solution
The solution is power feed in - the strips even have extra tails for power as well as the three wires for power and data. You feed in extra power at each strip end, so for my 4 strips I feed in at 5 points.
But how do you feed in power? In some cases you could simply power your longer strip at both ends and not have enough drop to the middle to notice. But I don't have power at the other end.
But actually it is possible to feed in even with just power from one end. The reason is the resistance of the wires, these are classic Chinesium™thin wire. If you actually have some thick good quality copper wire you can run and extra power lead the whole length and feed in at each strip end. This is what is in the WAGO boxes in the image.
Merry New year!
P.S. my son sells the controllers and stuff, https://hiwtsi.uk/
Update: Measuring resistance on the 50 LED strip power lines showed 1Ω but the leads were 0.1Ω, so 0.9Ω. A similar length of copper wire registered 0.4Ω, so 0.3Ω, so ⅓ of the resistance.
James did a video :-)
How are those Wago boxes going to handle a few inches of snow weighing down on them?
ReplyDeleteProbably lot well, as which point maybe gel boxes. We’ll see.
Delete"some thick good quality copper wire" - Read the packaging carefully. as I now have.a roll of speaker cable (wanted some hookup wire for a bunch of reed switches and the like in workshop) that's Copper Coated Aluminium (CCA) :-(
ReplyDeleteIndeed. This is decent stuff from RS.
DeleteI've never checked, but are Wago boxes waterproof? Would some small IP-rated boxes be better?
ReplyDeleteOur snow proof (today), we'll see. There are gel wago boxes but over £20 each.
DeleteI've phased out all my 5v WS2811 LEDs and gone for 12v to overcome voltage drops. Also I don't run them at anywhere near 100% brightness, 30% is usually adequate at night and also helps reduce the maximum current draw.
ReplyDeletebuildalightshow.com are a UK supplier that have LED strings pre-terminated with weatherproof connectors, thicker cable, and they also sell T splitters, extension leads, etc to inject/balance power along the string. They also make pre-punched mounting strip for these 12mm pixels which might've saved you having to do so much drilling (and also simplify aligning things straight!).
Indeed 12V does help.
DeleteVery nice. I moved away from 5v to 12v my self, and regulated rather than resistive, as the votalge drop was getting too much. I've got approx 4000 LEDs in my "show" at the moment and it does get quite bothersome to have to power inject every 1.5-2 strips, with 12v its every 3-4 strips, and if i'm not running 100% brightness (why would you, 30% is more than ample!) I can push that out to 5, sometimes 6 strips. The sheanigans comes with having to either bond the 0v or have a level shifter than can operate fast enough for the ws2812's data pin.
ReplyDeleteI generally dont run more than 800 in a single string.
In the US theres a company (Mattos Designs) that have a newer design of the standard pixels (EVO 12mm Pixels) and they seem to work exceedingly well, despite being thin wire. Even not using those, the difference between the 'unbranded' or 'alphabet soup' amazon specials and the "good" stuff from the likes of Ray Wu is night and day.
PSU wise, theres only one choice, a Meanwell PSU, RSP or equivalent, as anything else makes so much RFI that your local ham will be on you quicker than you can say QRM. I personally have standardised on the "xconnect" connector for the lights, and its great! 3 Pin, keyed, M/F cable with a grommet and compression with a screw on fitting. I've had one failure of a cable in 6 years, even emigrating and taking them from the UK -> US. For Power injection in the yard, I've got "pond cable" to a box with the meanwells in (in my case bud industries NBF-32022 or NBF-32016's) and then have a T at wherever i need to inject power.