LEDs from Dubai (2021)
hackaday.com
hackaday.com
bigclivedotcom: The lamps you're not allowed to have. Exploring the Dubai lamps: https://www.youtube.com/watch?v=klaJqofCsu4
First thing is voltage, 120/230V is not suitable for LEDs, if lamps would have an external 12V or 3V power supply a few centimetres away from the LED, this would be great.
The second thing is, that lamps need some kind of (passive!) cooling solution, to remove the heat from the chip. A lot of lamps are more or less closed and heat up as a whole. This is really bad for all the electronics, and probably the main reason why LEDs fail early.
The nice thing about newer filament bulbs is you can get 1600 lumen bulbs that are rated for enclosed fixtures now.
More here: https://en.wikipedia.org/wiki/LED_filament
Have you used these LED filament bulbs? They are very good, the quality of the light is much better than the older style LED bulbs.
One can get perfectly nice drivers and perfectly nice LEDs for less than $25 all in. Sure, many people prefer paying less for a screw-base lamp, but the result is not as good.
Sometimes there's just a basic dropper cap circuit, though. Those flicker but not too badly. The LED design in these is different than in a discrete LED, with the phosphor being quite thick and having a distinct slow fade/afterglow when switched off. I think in this case they basically use the phosphor to smooth out flickering instead of electronics.
Tight enough to hold light bulbs, thoroughly time tested.
USB power adaptors are super cheap and durable and the existing designs may be used.
In either case, you'd need a very beefy DC power supply somewhere to get enough current, or individual power supplies scattered inside walls, etc. which sounds like a maintenance nightmare.
I.e. https://www.ledsupply.com/led-bulbs/slim-recessed-led-light (arbitrarily chosen, not an endorsement)
It is with many in series, which is how the vast majority of lamps are made today. This lowers the current and reduces resistive losses.
Some lower spec lighting devices might take 120V and run LEDs in both series and parallel, but as LEDs fail, the rest get more current, leading to more failure… positive feedback loops for the win!
Perfectly-fine if you put them in a series chain. In fact you reduce power losses at higher operating voltages.
iirc (and I may not be remembering correctly), heat is what causes the degradation. Cutting power makes the LED run cooler.
For personal use at home it's important to buy high quality lightbulbs for this reason. Cheap ones will cut costs on cooling and fail prematurely or experience degradation if they don't fail. Better quality bulbs will last longer with less degradation. It can be hard to evaluate what's good; lots of companies will sell you cheap crap at inflated prices. Ikea uses solid metal bases on many of their bulbs which helps with heat (they use good CRI emitters too). I suspect weight might be a good heuristic to evaluate quality. Also avoid the high power ~1600 lumen ones, it's common for them to fail early even for the higher end ones, they just make too much heat to dissipate in the standard bulb form factor. Afaik Ikea eventually discontinued their 1600lm product, probably for this reason.
as an aside, when are we going to get a usable DC power and control standard for lighting?
I worked on a similar system a while ago for personal use. 300 watts of BLX COBs. Prototypes were good but they ran very hot (105 degrees) with the cooling system I had on them. Improving cooling and refining the design past the crude prototype would have made it too expensive to be practical for me, or for the market if I chose to sell it.
I'm probably going to be building a new house in a few years, it'd be nice if I could run 48v wiring throughout the house with standardized connectors and control modules. The age of 120/240v with screw socket bases needs to end. But I doubt the industry will have standardized on a DC system by then.
I wonder if there are any actively cooled fixtures on the market for standard lightbulbs. The common recessed in-ceiling fixtures are not great for thermals, the closed top blocks natural convection and traps hot air. A slow (silent) fan should do a lot to help with bulb longevity. I might end up doing a custom design for my house if there's nothing on the market.
since our primary activity is metal sculpture....we really don't have to deal with cooling issues. 10-20 pounds of metal, even steel, makes a _really good_ heat sink, even if it is isn't optimized for maximum convection. and now your light elements are little 3cm circles a couple mm high, and you can tuck them wherever you want.
it wouldn't be too hard to make you own standard. the constant current drivers often have pretty wide input ranges, especially if you can stick with simple bucks. the part where I really kinda fell down was connectors oddly enough. 3 pins, moderate current, few cycles, low cost, high contact reliabilty. anyone with better connector-fu than me have a suggestion?
USB-C might work. USB PD supports 5a at up to 20v, looks like there's also a higher power 50v 5a spec coming up. But if you're using custom PCBs on both ends you don't really care about the PD specification, as long as you're using good quality cables you can treat the connector/cable as a dumb wire that supports sending 5 amps down a few pins. The data lines may also be useful for sending back data from the emitter module, if you had any need for that.
Desktop computers use the Molex Mini-Fit Jr connector for ATX and PCIe power connectors. 6-pin PCIe power cables should be easy to source on the market, you wouldn't need to get custom cables manufactured. Those can carry ~150w. Might also be possible to cheaply source cables with just a 2 or 4 pin connector?
Seems like what's lacking isn't a standard (or rather the basis for a standard), but a market leader to say "we're gonna back this". But you've got way more insight than I do and I'm undoubtedly underestimating the effort.
Reducing power will help a lot with this, less current flowing through the power supply and less heat generated.
https://www.kron4.com/news/bay-area/bay-bridge-lights-set-to...
> “It’s a challenge of the current lights. They’re good but they have to exist in an area that has rain, fog, high winds, grime 24/7, vibration, expansion and contraction,” Davis said.
This has nothing to do with brightness or with the bulbs being LEDs. Their hardware is not properly suited for the environment it's being used in. If you put an Arduino in your car, don't be surprised when the non-automotive-grade electronics fail after a few years. The EEs must have not done a great job when initially designing this light project. From to the project's website (linked by your article):
> They must be replaced with a new system that is custom engineered to perform in the harsh environmental conditions of San Francisco Bay.
Maybe it's the scale, relative inaccessibility, or remote control that's the problem.
Honestly, I never loved the 'light show' effect anyway - maybe they should just light the suspender cables with normal lights and call it a day.
EDIT: For reference, here is the bridge before Baylights: https://commons.wikimedia.org/wiki/File:The_Oakland_Bay_Brid...
Other major port-cities around the world, with comparable climate conditions, have presumably transitioned to LED lighting over the past decade - why can't they save taxpayer's money by simply buying-up whatever Valencia or Singapore is using instead of having their own NIH Syndrome and insisting an entirely bespoke system just-for-them be used?
Now I wonder if they will actually last.
https://en.wikipedia.org/wiki/Jacques_Cartier_Bridge#%22Livi...
If the lights need to last 10 years, then the mechanical & electrical engineers can make a design that will last 10 years. That's not hard to do. The reason many LEDs, especially consumer LEDs, fail early is due to excessive cost cutting.
It's okay for it to just live on in memory.
The only reason you "can't buy them" is because you wouldn't (or at least people wouldn't). You can't easily tell how good the LED setup is in the bulbs, and price isn't necessarily a good indicator, so you're unlikely to pick the more expensive item.
Suppose you decided to carry them and they cost more, both from a material perspective and a reduced repeat customer perspective. Cheap competitors in stores won't just go away and they'll be on shelves next to them. Brand recognition and/or loyalty will only go so far and way too many people will prefer the cheaper cost. So the manufacturer/distributor have to provide both or risk losing sales. Now there's an extra sku in the mix and I'd wager that even with brand recognition the cheaper ones will outsell the Dubai ones, which makes the distribution overheads even more unpalatable. And so on.
I'm sure they've done their research and it doesn't add up from a business sense. It works in Dubai because the regulations eliminate part of the race to zero.
Even selling them directly online is problematic because of distributor territory, exclusivity etc. If the manufacturer competes with its distributor network (that they rely on) then that doesn't end well either.
I doubt it's any sort of conspiracy by 'big led' to keep you from buying them, but is more to do with mundane and unfortunate things like above.
I still want them though.
Example : https://www.lighting.philips.co.uk/consumer/p/led-bulb/87195...
Compared to the Dubai lamp it still drives the LED filaments at 0.25 W each, but the driver circuitry is traditional and doesn't have the unusual features from the Dubai lamp. These include component-level redundancy and automatic brightness compensation (this breaks dimmers, so architects hate the bulb mandate).
Nothing ruins a nation's (carefully cultivated) high-tech luxury image like all the bulbs dimming simultaneously with the grid voltage!
The real question is what is needed for these to be dim-able?