[HN Gopher] Next generation LEDs are cheap and sustainable
___________________________________________________________________
Next generation LEDs are cheap and sustainable
Author : geox
Score : 167 points
Date : 2025-03-17 02:42 UTC (4 days ago)
(HTM) web link (liu.se)
(TXT) w3m dump (liu.se)
| hulitu wrote:
| > Next generation LEDs are cheap and sustainable
|
| Sustainable ? Made from tropical forest trees ?
| ForTheKidz wrote:
| It seems their environmental impact was defined in terms of the
| (environmental) cost of mining gold. "The greatest
| environmental gain would instead be achieved by replacing gold
| with copper, aluminium or nickel, while maintaining the small
| amount of lead needed for the LED to function optimally."
| ilove_banh_mi wrote:
| "sustainable" was incorrectly translated from the Swedish
| "miljovanliga" which instead means "environmentally-friendly"
| ("sustainable" is "hallbar" in Swedish)
| SoftTalker wrote:
| It's a marketing term anyway, it doesn't mean anything.
| etiam wrote:
| I came back to say pretty much that. Since these buzzwords as
| used in most of society today barely mean anything at all,
| the writer was probably happy enough to namecheck _something_
| vaguely positive and endorsed to do with environment stuff.
|
| It would have tickled my funny bone if they'd gone with
| "Green" in this case.
|
| (Thanks nonetheless to ilove_banh_mi, for setting the record
| straight)
| KennyBlanken wrote:
| The article is about people trying to engineer electronic
| devices that take into account their full lifecycle?
|
| The knee-jerk cynical "hot takes" on this site are getting
| really tiresome. It's intellectual cowardice and laziness.
| Anyone can say this sort of zero-calorie edgy nonsense
| userbinator wrote:
| Whenever I see "sustainable" these days, I think "they must
| mean sustainable profit --- due to planned obsolescence".
| hunter2_ wrote:
| It just means that you can continue indefinitely with no end
| in sight. End could come from financial problems, consumer
| preferences to help the environment, environmental
| regulations, supply chain issues, and all sorts of other
| things.
|
| It's like the sustain pedal on a piano: nothing actively
| dampens the sound, so the sound will continue for quite a
| while longer than is typically required.
| NegativeLatency wrote:
| Current LEDs are pretty cheap and comparatively sustainable (to
| other lighting technology), but lots of LED based lighting
| devices ship with:
|
| - non replaceable batteries (flashlights)
|
| - unreliable drivers that fail before the LED does, or kill the
| LED by heat or excessive voltage
|
| Happy to see people working on new LED tech but the downstream
| effects of selling disposable stuff has to be much worse?
| WalterBright wrote:
| The life of indoor LED bulbs has improved over the years. But I
| learned to only install them in vented fixtures.
| zerocrates wrote:
| It's LED fixtures that I have a problem with; they're very
| common since it's easy to make them in various shapes and
| things, but when a component fails more often than not it's a
| "replace the whole fixture" situation.
|
| My parents have a ceiling fan that came with an LED light,
| which broke. It was barely under warranty for the LED part
| still and the manufacturer sent out a new light module,
| except they've changed the fan a little over the years and
| the new module doesn't fit on the old fan... they ended up
| having to send a whole new fan.
| ethbr1 wrote:
| Afaict, this is a case of the primary customer: contractors
| and builders.
|
| They don't care if bulbs are replaceable, since their
| lifetime is limited to build -> sell.
| TylerE wrote:
| Actually with fans specifically it has to do with
| legislation that requires them to not be able to mount a
| standard Edison bulb.
| bfdm wrote:
| What? Why?
| toast0 wrote:
| I'm not familiar with ceiling fan regulations, but
| regulations for recessed lighting (can lights) in some
| jurisdiction mandated connectors other than edison screws
| in new construction as a way to force out incandescent
| bulbs.
|
| IMHO, pretty unnecessary, as once the PAR30 dimmable LED
| bulbs got good, I don't think many people would prefer
| incandescent. OTOH, I think they were pushing compact
| fluorescent, which I don't think ever got very good.
|
| For new construction now, the LED fixtures can be mounted
| without a can, because they put out way less heat, and
| some of them are very thin, so they may not penetrate
| beyond the thickness of the ceiling, which is neat. But
| for retrofitting, putting a screw in bulb is nice and
| easy.
| KennyBlanken wrote:
| I still have several Cree bulbs that are at least a decade
| old, I think more like 15 years old. None have failed.
|
| Everyone I know who complains about LED bulbs failing, you
| ask them and they admit to buying the cheapest ones they
| could find.
| mhb wrote:
| I have an original Philips EnduraLED that still works fine.
| zdragnar wrote:
| I dropped good money somewhat early on for LEDs that were
| supposed to last at least that long (some name brand, no
| idea what at this point), and I don't think I even got a
| year out of them.
|
| At that point, I decided to just buy the cheap ones because
| that was easier than dealing with the warranty process
| anyway.
| TylerE wrote:
| The trick is figuring out where in the product lifecycle
| you are. Early on you want to go cheap, because you'll be
| able to get way better for cheaper in a year or two
| anyway. Later on once the technology has matured this is
| less true.
| NegativeLatency wrote:
| I've found generally the more expensive ones last longer,
| but I just had a Phillips HUE bulb die on me (the LED is
| fine I think but it flashes rapidly so I'm suspecting the
| driver is bad)
| pkolaczk wrote:
| Rapid flashing is usually an indicator of a LED failure,
| not the driver. In my experience (and I fixed many LEDs),
| drivers almost never fail - it's always the diodes, dying
| from too much heat.
| pkolaczk wrote:
| I've had many expensive Philips or Osram bulbs failing.
| stevekemp wrote:
| I just replaced two OSRAM LED "bulbs" in my bedroom, and
| paid 15 euros each for them. 30 euros for two lights feels
| insane, and yet I know I paid something similar for the
| previous ones about five years ago.
|
| My issue with LED bulbs is that they don't fail per se,
| instead they get progressively less and less bright over
| time. It's a slow fade rather than a sudden explosion.
|
| (I've gotten into the habit of writing the installation
| date of all new bulbs on the stem as I insert/install them.
| Just because I want to track how long they last.)
| y33t wrote:
| Heat is the real killer for LEDs. Most LEDs sold for home
| lighting do not have very good thermal regulation, possibly
| as a planned obsolesence "feature".
| pkolaczk wrote:
| Yes, even expensive Phillips LEDs heat up to 100 C. There
| is no way they could last the designed 50000h at that temp.
| Liftyee wrote:
| Granted, there is usually a rechargeable alternative to any
| product using non replaceable batteries. Or one can use
| rechargeable AA/AAA/etc. that recoup their cost within a few
| charges.
|
| For the consumer rechargeable always makes sense, but I think
| there's an incentive for stores to not push those products -
| why sell rechargeable flashlights when you can sell ones that
| gobble alkaline cells and get your customers coming back for
| batteries?? Is there any way to avoid this problem besides
| regulation?
| NegativeLatency wrote:
| There's a lot of 18650 compatible flashlights and stuff, but
| some of them have the battery sealed inside. I have a couple
| of bike lights and flashlights that have this issue and I've
| cracked them open to replace the batteries, but it's not a
| regular person thing to do.
| stephen_g wrote:
| Yeah, for parts of my house I have renovated I put in LED
| fixtures with separate drivers that sit up in the roof cavity,
| and none of them have failed (out of about a dozen lights) in
| the eight years since. Meanwhile, elsewhere in the house I have
| some older fixtures that were designed for incandescent bulbs
| and have been through a bunch of LED replacement bulbs for
| them.
| colechristensen wrote:
| Yup. The LED diodes themselves will last for decades if
| treated properly, the power electronics though are very often
| made with extreme cut corners and the thermal design is awful
| meaning bulbs much more expensive and environmentally
| impacting than a bit of glass and milligrams of tungsten wire
| are failing in similar time spans. Somebody should do an
| environmental impact study of shitty LED bulbs vs
| incandescents to determine if the manufacturing impact
| difference makes up for the energy savings.
| eternityforest wrote:
| I don't understand why there's no startups making open source
| modular electronics.
|
| A collection of maybe 50 well chosen modules could handle at
| least part of pretty much everything, while allowing for
| upgrades as tech improves.
|
| A microwave and a dishwasher and a dryer could all use the same
| controller and the same display module. A desk lamp and a
| flashlight could use the same LED and driver.
|
| The current modular systems are educational or hobbyist
| oriented, or they try to do stuff that crosses high bandwidth
| links and needs lots of pins, but there's not reason we can't
| have standard LED drivers and other simple stuff like that.
|
| The whole range of modules would probably be pretty cheap, it's
| just a matter of convincing everyone to use them, which I guess
| is why nobody does it.
| iancmceachern wrote:
| It's because you would need open source ICs for that, and
| that'd a whole complex multinational tool chain.
|
| The modules you speak of exist, they're ICs. Most electronics
| now are just ICs and traces on a board. The real challenge is
| the IC tool chain is very complex and very not open.
|
| It would do no good to have open source modules that are just
| traces and then a bunch of closed source ICs. This is what
| Sparkfun, adafruit, etc. do. It's great for engineers and
| hobbiests but it doesn't get to the root of the value you
| propose.
|
| The real value is in the ICs, those are the magic modules you
| speak of that need to be open source.
|
| Getting that to happen is a whole thing. Like getting
| ExxonMobil to share their oil rig designs.
| jononor wrote:
| I think that open-source modules are valuable even without
| open-source ICs. At least for may classes of genetic
| IC/modules there are many vendors of an IC, so one could
| have multi-source for the IC, to reduce reliance on a
| single vendor/source.
|
| It is becoming more and more feasible to do things
| software-defined, with a generic microcontroller being the
| core IC. I would love to see some projects for DC/DC power
| converters for example around a microcontroller with open
| software. This is a bit tricky because it needs to be safe,
| but in theory doable. Also need to be EMC compatible, which
| will require a lot of testing. Generally going beyond
| hobbyist requires much better QA than what most current
| open source hardware projects are willing/capable to do.
| Environmental testing, EMC testing, regulatory compliance,
| etc. Some exceptions might be vendors like Olimex.
| LargoLasskhyfv wrote:
| For stuff like this maybe
| https://colognechip.com/programmable-logic/gatemate/ would
| suffice?
|
| edit: Hrrm. Actually that seems a little bit overblown.
| Seems like they've upped their stuff. I just remembered
| them from a few years ago, when they had much smaller
| things on offer. Or misremember them for something else,
| were you could use them as something like 74xx replacement,
| with emerging support for open toolchains.
|
| But still, interesting. So I won't erase this ;>
| eternityforest wrote:
| Closed source ICs are currently pretty cheap, reliable, and
| there's so many of them that if one became unavailable, a
| module could be redesigned to use another (Losing firmware
| compatibility if you had to switch to a new MCU, but
| keeping hardware compatibility).
| lm28469 wrote:
| > A microwave and a dishwasher and a dryer could all use the
| same controller and the same display module.
|
| The real question is do we even need displays for those? A
| few buttons and a knob is all we need
| xnzakg wrote:
| A display goes a long way when troubleshooting, instead of
| having to dig out the manual and figure out what the
| specific combination of blinking LEDs is supposed to mean.
| Tomte wrote:
| A phone app can translate that. Yes, dependence on phone
| etc., but the company I work for is doing that for
| industrial automation components, and users seem happy.
| aziaziazi wrote:
| Well the "ER07" on my wash machine display isn't very
| informative neither.
|
| OTOH ~10 leds with logos on the 25yo water heating
| machine works almost perfectly to inform be the current
| state (auto/manual) and low/high pressure, restart
| required and maintenance required.
|
| The temperature is displayed with a needle dial.
| vel0city wrote:
| It does when you look at the code definitions in the
| service manual just inside the chassis. And then you can
| enter the diagnostics mode and have it do more self tests
| and report back exactly what's going on.
| aziaziazi wrote:
| I'd love to try that diagnostic mode but never eared of
| something like that. My machine is a recent Samsung (EU).
| vel0city wrote:
| https://www.samsung.com/us/support/answer/ANS00092622/?ms
| ock...
|
| They also document the error codes:
|
| https://www.samsung.com/us/support/troubleshoot/TSG100009
| 97/...
|
| But as mentioned most big appliances usually have a small
| service manual tucked inside the chassis somewhere. Those
| will have these instructions and the table to decipher
| the error codes, along with some basic troubleshooting
| steps. It might also include official part numbers to
| replace components which might have failed. This is often
| true for washing machines, dryers, fridges, dishwashers,
| stuff like that.
|
| On my GE units it even stores recent codes in case it
| experienced multiple different issues while running. You
| can cycle through the history in the maintenance mode.
|
| I do agree though, in the end you still probably need the
| table to decipher the error codes.
| aziaziazi wrote:
| That's great thanks! Your post is in my favorites for
| future references.
| LargoLasskhyfv wrote:
| Could have Blutooth instead and _cast_ it to your
| smartphone /watch, or whatever.
|
| Think wireless JTAG for dummies/consumers.
| Ray20 wrote:
| Why not? Considering how cheap they are (we are talking
| about less than 10 dollars for 4-6 inch display with
| relatively high resolution and controller for this
| display).
| lm28469 wrote:
| Something "being cheap" isn't really a reason to add it
| to a product.
| piokoch wrote:
| "I don't understand why there's no startups making open
| source modular electronics." There is, maybe it is not a
| startup per se. In Shenzhen there is 500 companies that will
| produce whatever you need in whatever amounts you need, could
| be 10, 100, 10 000 000.
| jononor wrote:
| Why would a startup do that? Hardware is low-margin
| difficult, capital intensive, long sales cycles, long rampups
| until revenue, volume sales are very trust-based (hard to get
| in when not established), expensive recalls, product
| compliance, etc. In addition the trend for the last 30 years
| of electronics is integration, completely opposite of
| modularization. I am very pro open source hardware and
| software (and contribute to both) - but I find it completely
| understandable that there are few startups/companies in this
| space.
| tomcam wrote:
| ^ This answer outlines all the issues perfectly.
| ACCount36 wrote:
| What's the business model?
|
| I could, for example, design and make an open source
| controller board suitable for a microwave oven. But how do I
| sell microwave ovens competing on price with people who have
| been building microwave ovens for decades and have basically
| perfected the art?
|
| How do I stop companies in China from taking my controller
| design and selling it at half the price?
| mapt wrote:
| I'd imagine there are. In Shenzhen.
| fxtentacle wrote:
| "I don't understand why there's no startups making open
| source modular electronics."
|
| I would love to do exactly that, but so far I have not found
| any way how I could do that and still have a regular salary.
| Of course, I could do it for free as a generous gift to
| Chinese factories who will then produce things and flood
| Amazon with it ... but they won't reciprocate and donate back
| to the Open Source project. The OS project will quickly
| stagnate and future development stops.
|
| The fix is that the Open Source project needs to sell
| hardware, or else there's no revenue to fund further
| development. And that means you now also need FCC and CE
| certification. And you need patents. Or else, Chinese
| factories will flood Amazon with your design. (but without
| paying for FCC/CE)
|
| But now that you can successfully sell hardware to fund
| future development and you can fend off Chinese clones, your
| project is not really "open" anymore. It's kind of like an
| OEM module that is "source available". Like the Adafruit kits
| that you can order from Amazon/Arrow.
| ffsoftboiled wrote:
| "As we enjoy great advantages from the inventions of
| others, we should be glad of an opportunity to serve others
| by any invention of ours; and this we should do freely and
| generously,"
| mitthrowaway2 wrote:
| Who are you quoting?
| LargoLasskhyfv wrote:
| Are you aware of https://m5stack.com/ &
| https://github.com/m5stack and where would you put them,
| regarding the topic?
| thawawaycold wrote:
| one way to put them would be on a list of PRC funded
| startups, for instance. also I have no idea whether you
| worked with their hardware before and at which level; I
| have, and their concept of "open" source HW is very
| different from what OP is talking about
| ajsnigrutin wrote:
| Businesses don't care about opensource, and they already use
| standard electronics, just not modular, because modules are
| expensive.
|
| E.g. many Haier/Candy mostly use esp32 microcontrollers, led
| displays don't even need modules, lcd displays use usually
| one of few standards, etc.
|
| A cheap microwave costs 50euros, a washing machine 200,
| that's retail price with a 5year warranty, sometimes even
| with delivery, there is no place for modules that noone will
| actually use.
| gosub100 wrote:
| I'm not sure if this is the same thing, but I'd like to see a
| product family that can be configured to replace controller
| boards on a wide family of appliances. For instance, a
| generic compressor/thermostat controller that will work as a
| replacement on ALL models of refrigerator for the past 20
| years. It would work based on jumper settings or loops that
| you add/cut that would be qualified and tested for each
| model. It's working with power levels that could burn your
| house down, so safety would need to be paramount. But
| basically all appliances do the same thing, just at different
| voltage and current levels. There should be a market for a
| common replacement set.
| mike50 wrote:
| Dryers and microwave ovens do not require electronics. LED
| lamps with a wall wart that unplugs already exist.
| nottorp wrote:
| > unreliable drivers that fail before the LED does, or kill the
| LED by heat or excessive voltage
|
| That. I have a rather enclosed (little ventilation) ceiling
| fixture that in theory is supposed to be specced for up to 2 x
| 75 W incandescent. You'd think it will handle 2 x 9 or 12 W led
| "bulbs" just fine, right?
|
| It killed one averagely priced led "bulb" every 2 years until i
| switched to a slightly more expensive brand.
| xaldir wrote:
| There is indeed a difference between specced for
| "incandescent bulbs wont start a fire" and "it's warm enough
| to cook the electronics of your led bulbs"
| nottorp wrote:
| Thing is, touching it (the enclosure not the led bulbs)
| with my bare hands it's just slightly warm. I wash my hands
| with water much hotter than that.
|
| Edit: and I just realized, the mac mini i'm mostly typing
| code/emails/comms on idles at less than the 2 x 12 W bulbs
| above it...
| pjc50 wrote:
| > - non replaceable batteries (flashlights)
|
| Not encountered those? You people need to get onto Aliexpress
| where the good stuff that takes 18650 batteries is.
| rob74 wrote:
| One thing I learned the hard way is that various older relays,
| timers, dimmers etc. will kill LED "light bulbs", but most of
| the time not instantly, but over several months/years. When we
| bought our current apartment 10 years ago, I had the common
| sense to replace the dimmers with newer "LED-approved"
| versions, and also replaced one of two relays because it was
| broken, but then the remaining relay over several years
| destroyed several "light bulbs" and one (fortunately not very
| expensive) lighting fixture with non-removable LEDs, until it
| dawned on me that the relay was to blame. After I replaced it ~
| 5 years ago, no more problems.
| rockostrich wrote:
| I think it's a good idea in general to just try and replace
| every switch and outlet if you buy a home that was lived in
| for an extended period of time. We moved into a home that the
| previous family lived in for 30 years and I've been working
| my way through replacing everything. I've found some crazy
| work in some of the junction boxes. Most weren't grounded
| which isn't super surprising. Many were wired incorrectly
| which is a little less surprising.
|
| Also it's a good exercise in making sure the electrical panel
| is labeled correctly. Ours was somehow only labeled like 75%
| correctly.
| matthewdgreen wrote:
| I replaced all the three way switches in my (100+ year old)
| home and found loads of ugly cloth-covered wiring and even
| "knob and tube" in a few places. So this was a great
| exercise. Unfortunately I miswired one circuit so badly
| that my metal chandelier became a live electrical death
| trap, which I only found out during the inspection when we
| sold the place. I cannot recommend professional
| electricians enough.
| quickthrowman wrote:
| If I bought a house I would replace every receptacle and
| switch with a commercial spec grade version, residential
| grade wiring devices are uniformly awful.
| techdmn wrote:
| Labeled incorrectly in Sharpie is the best! I agree, with
| the caveat that I have worked as an electrician
| professionally. Generally this is how home ownership works.
| You go over everything, find all the weirdness that the
| previous owner did, and fix it up. Years later you sell the
| house, and the process starts all over again. ;-)
| amelius wrote:
| And nobody keeps a logbook.
| mouse_ wrote:
| See: Bram's Law
| https://web.archive.org/web/20170629144859/http://www.advoga...
|
| > The easier a piece of software is to write, the worse it's
| implemented in practice.
|
| In this case, as LEDs become easier and more accessable to
| implement, they are implemented worse in practice.
| superkuh wrote:
| It doesn't even have to be unrelible/cheap drivers that fail.
| Even name brand Cree/Phillips/etc stuff have drivers that will
| fail rather quickly if your wall current is at all dirty.
|
| The effect of this is LED lightbulbs that have a shorter
| lifetime than incandescent lightbulbs did in my apartment. At
| least incandescent and halogen bulbs were just a bit of glass
| and wire: explicitly disposable. But LED bulbs are full of
| parts and boards and the like and generate far more waste.
| saturn8601 wrote:
| Maybe someone can answer this question for me but I have yet to
| find a LED bulb that can replicate the 'full spectrum' aka
| sunlight feeling of a Halogen bulb. I just love the color
| warmth of Halogen and LED just can't seem to replicate it.
|
| I have have bought a lot of LED bulbs in search of this. Is
| there something that I am missing or is LED just not capable of
| producing the same spectrum of color as Halogen? When I look at
| my items under LED and then look at them under Halogen its like
| the items become vivid.
|
| The best I could find is this company called "Waveform
| Lighting" that sells very high CRI bulbs for like ~$20 a bulb
| (with the second place being Soraa bulbs) both are some of the
| best LED bulbs I've used but no where near the effect of
| Halogen. What am I doing wrong?
| trox wrote:
| Maybe you find this interesting:
| https://optimizeyourbiology.com/light-bulb-database
|
| It's a database of light bulbs tested using a 1-meter barium
| sulfate integration sphere and calibrated lumen
| photospectrometer. Although no LED comes close to the Halogen
| in terms of CRI, it is very informative.
| opwieurposiu wrote:
| Is the gold in LEDs just in the bond wires?
| lightedman wrote:
| Occasionally the contact plating for surface mounting is also
| gold-plated. I can think of a couple Nichia LEDs from work that
| have gold plated electrical and thermal contacts.
| softgrow wrote:
| Surprisingly or not, isn't a very new idea
| https://en.wikipedia.org/wiki/Perovskite_light-emitting_diod...
|
| Note that extending the lifetime is key to taking advantage of
| their lower base material cost. Lot of work needed there.
| WalterBright wrote:
| When I was fiddling with LED circuits back in the 70s (!) I
| experimented with turning the LED on and off with a square wave.
| If you turned it on and off rapidly enough, your eye did not
| notice it, and your eye perceived it as fully bright. (Adjusting
| both the frequency and duration of the "on" part.)
|
| Hence, you could get some decent power savings doing this.
|
| I wonder if this is commonly known. I've mentioned it to a couple
| EEs over the years, and they were able to reduce the power
| consumption of their devices.
| WalterBright wrote:
| I have a couple LED night lights that are triggered by a
| photocell to only turn on in the dark. I've often wondered if
| the trigger circuit consumed more power than just leaving the
| LED on.
| nine_k wrote:
| It likely consumes next to no power: a proper switching
| MOSFET has negligible resistance when open, and has a very
| high gate resistance, so the photo cell does not have to
| produce any significant current. Possibly the current-
| limiting resistor in the power supply of the LED circuit
| dissipates more than the trigger circuit.
| throitallaway wrote:
| PWM. This is widely used method for dimming.
| hunter2_ wrote:
| How could the same modulation achieve "dimming" and "fully
| bright" simultaneously?
| jfim wrote:
| The apparent brightness is caused by the ratio of on/off
| and is called the duty cycle. 50% brightness would mean
| that half the time the light is on, and half the time the
| light is off.
|
| If the cycling of the light on and off is done at say 10kHz
| it's perceived as a dim light.
| gizmo686 wrote:
| For traditional lightbulbs, a PWM signal actually makes the
| light noticeably dimmer, and has a very simmilar effect to
| simply reducing the current. This is because the mechanism
| for them is heating up the filement, which happens on a
| much slower time scale then the PWM duty cycle.
|
| In practice, traditional dimmers are not quite PWM as they
| do not generate a square wave. Instead they generate a sin
| wave with portions of each cycle clamped to 0.
|
| LEDs already need driver circutry to condition the
| relativly high AC voltage into a stable lower voltage DC.
| Dimmable LEDs create a stable DC power supply from the
| chopped up AC power, then use the width of the active
| portions of the AC as a signal to drive their own dimmer
| logic.
| fc417fc802 wrote:
| That's a good PWM explanation but I think GP was asking a
| different question. Walter claimed that if the PWM was
| high enough frequency you would perceive it as full
| brightness while using less power.
|
| It obviously wouldn't work that way when lighting a room,
| but what about for an LED indicator light that you look
| at directly? I don't know enough to form an opinion.
| MadnessASAP wrote:
| Without any more information on frequencies and
| measurements it's impossible to know. My guess is either
| A) They did not perceive the dimming, and/or B) The
| frequency was high enough that the inductive and
| capacitive effects of the circuitry became relevant and
| was filtering the PWM signal to DC signal that still drew
| the same amount of power as it did when fed the full
| voltage DC signal
| mrheosuper wrote:
| you dont. But your eyes perceive brightness non-linear,
| which means to your eye, 80% of brightness is very close to
| 100%
| codebje wrote:
| The measurable brightness of the LED is a straightforward
| sum of the times it's on and the times it's off. Shift the
| ratio so it's off more than it's on and it gets dimmer.
|
| The "fully bright" part is a consequence of human vision.
| Your brain is making sense of limited, noisy information
| coming from your eyes. A flickering light appears brighter
| than the light in steady state, lots of still images shown
| in rapid succession look like they're moving, as far as you
| can tell you can perceive the full range of colour out of
| the corner of your eyes, and the dress could be either
| colour.
| CorrectHorseBat wrote:
| Also (and I think more important, but I might be wrong),
| we don't perceive light intensity linear but logarithmic.
| A 50% duty cycle does appear brighter than half as
| bright. A 90% duty cycle might be only barely
| perceptible.
| notfed wrote:
| It's also widely known to cause headaches. I swapped out all
| my PWM bulbs and couldn't be happier. More info here:
| https://flickeralliance.org/
| WalterBright wrote:
| I have a video projector, and if I flick my eyes across the
| screen I can perceive the separate R G B frames. But just
| watching it, it's fine.
| KennyBlanken wrote:
| That's DLP and it's because DLP uses a color wheel at 3x
| the frame rate.
| WalterBright wrote:
| I know. I was just pointing out that flicker doesn't
| affect me, for which I'm glad. I was a bit concerned
| before I bought it, due to the complaints about the
| flicker.
| toast0 wrote:
| Not only DLP. Some laser projectors use a color wheel to
| get the same effect; other laser projectors use multiple
| lasers, but pulse the colors individually and you get a
| similar effect; probably there are some laser projectors
| that do all colors simultaneously too, just as there are
| some DLP projectors with 3 DLP surfaces and prisms/etc to
| split and combine the light. My laser projector does the
| pulsing, I find it slightly less distracting than I
| remember color wheels being, but it's very similar;
| thankfully the family has gotten used to it; I only
| notice it on content that encourages a lot of fast eye
| movement.
| CarVac wrote:
| Scanning displays like a laser projector or a CRT will
| flash any individual spot but the illumination is almost
| continuous, so people have less issues with them.
| toast0 wrote:
| I'm talking about laser illuminated panel projectors used
| for viewing film or video content, not scanning lasers
| used for light shows. Scanning a laser beam is a lot more
| difficult than scanning an electron beam, so rasterised
| displays from a scanning laser are limited compared to
| CRTs.
| globular-toast wrote:
| I believe the colour wheels now spin twice as fast which
| may reduce the effect somewhat. But for me it's not a
| very nice effect which is why I use a 3 chip projector.
| Unfortunately 3 chip DLP is prohibitively expensive
| (cinemas use them), but JVC DLA projectors are good.
| Although it looks like the newer 4K models are also
| prohibitively expensive :/
| 153957 wrote:
| I can not stand the DLP projectors, so I got an Epson
| 3LCD, and have no issues with it, not crazy expensive
| either.
| globular-toast wrote:
| LCDs have typically been considered inferior for home
| cinema usage. The only advantage of them is the price and
| that they have no colour wheel. DLA is a sort of middle
| ground that is technically an LCD but works more like
| DLP. None of this matters if your room isn't set up right
| or you're projecting in a not completely dark room,
| though.
| Piezoid wrote:
| The interstimulus interval (ISI) for vision is much
| longer than most flicker rates or frame intervals in
| displays and projectors. However flicker can be perceived
| through temporal aliasing. For lighting, even simple
| motion in the scene can reveal flicker. Waving your
| spread fingers in front of your eyes is a sure way to
| detect flicker.
|
| What you're describing is likely saccadic masking, where
| the brain suppresses visual input during eye movements.
| It "freezes" perception just before a saccade and masks
| the blur, extending the perception of a "frame" up to the
| point in time of the sharp onset of masking. That's how
| you get a still of a partially illuminated frame instead
| of the blended together colors.
|
| I'm no expert in this, but if you're curious, check out
| the Wikipedia pages on interstimulus interval, saccadic
| masking, chronostasis, and related research.
| bjoli wrote:
| IKEA has, at least in Sweden, started publishing how much
| their lights flicker. I found that it is actually an upper
| limit for their lights. The dimmable ones flicker less for
| most of their dimmable range for example.
|
| Now, I only measured two bulbs, but I am pretty darn happy
| with those results. I also opened one of their chargers and
| haven't looked elsewhere for chargers since. The thing was
| even more well built than my apple charger (the 45w sjoss
| is actually quite crazy. The 30w had some issues)
| metaphor wrote:
| Perhaps less widely known is that if you market a commercial
| product that actually uses PWM to modulate LED intensity,
| you're liable to be litigated against by Philips for patent
| infringement?
|
| Wild...yeah, I know. Heard that from a buddy in Austin over a
| decade ago. Vaguely recall that he had to redesign using some
| sort of current driver instead to avoid the legal
| encumbrance.
| oasisaimlessly wrote:
| Probably no longer true; patents only last 20 years.
| metaphor wrote:
| To be fair, it's probably naive to blindly assume that a
| company like Philips, with a long history of litigious
| behavior, isn't playing patent continuation games.
| ioseph wrote:
| I thought this was very common knowledge, we used the technique
| in our first year EE project.
| sneak wrote:
| Not only is this widely known, it is the main method by which
| multicolor RGB lights can exist, because they are actually a
| package with red, green, and blue LEDs in them, where each
| color channel is individually "dimmed" using this technique
| (called pulse width modulation, or PWM) to be able to produce
| many more colors (much like a TV or LCD/OLED display).
|
| The white color produced by full-on of R, G, and B is quite
| ghastly, so modern ones come with an individual white LED (and
| frequently a second warm white LED) in the package for a total
| of four or five individual color LEDs in the single light (RGBW
| or RGBWW).
| fc417fc802 wrote:
| He's not talking about dimming. He's talking about the
| perceived brightness when you look directly at an indicator
| LED.
| nefarious_ends wrote:
| This is why I love HN! Only here you'll find the actual guy who
| invented dimming!
| WalterBright wrote:
| I should have patented it! Mwuhahahaha
| WalterBright wrote:
| I watched a fascinating video of a guy explaining, in detail,
| how vacuum tube radios worked. Quite a joy to watch.
|
| I'm glad I didn't take up Electrical Engineering as a major.
| All the fun of using signal generators and oscilloscopes is
| gone. Just program a Raspberry Pi to do it. or a circuit
| simulator on your computer. Sigh. EE is no fun without getting
| accidentally zapped by A/C once in a while or letting the smoke
| trapped in a transistor out.
|
| It's like hotrodding a car by plugging in a laptop. Ehhh no.
| saturn8601 wrote:
| Thats more 'computer engineering' no? EE also has things like
| Power Systems, RF, solid state if you want to go into chip
| design and the like.
| AnimalMuppet wrote:
| Nominative determinism strikes again! (Or is this anti-
| determinism?)
| Saigonautica wrote:
| It's widely known among EEs. It's used for lots of interesting
| things, such as temperature control, motor control and
| positioning, and LED lighting. You can do it in hardware old-
| style with a 555 timer or hex inverter, but most modern systems
| I've worked with do it with a microcontroller.
|
| An addendum to this that you may find interesting -- I've
| experimented with turning the LED on for a few microseconds at
| higher than rated current, then off for tens of milliseconds.
| The average current stays far below the specifications. This
| results in very high apparent brightness per unit of power
| consumption.
|
| Using the IV curve of the LED, this also let me eliminate the
| typical current-limiting resistor. The power savings are more
| than the power cost of the MCU that controls it (modern low-
| power microcontrollers are awesome).
|
| Anyway, the end result is a little LED + CR2032 cell + magnet
| that you stick to furniture, and it runs for about 3 years. I
| made it so that elderly people I know who wake up at night to
| go to the bathroom don't bump into furniture (especially in an
| unfamiliar place, like while traveling). Without creating a
| thing they have to think about often. If you're curious, I
| posted the code here: https://github.com/seanboyce/tinylight
|
| An additional one you might like: I did PWM for LED dimming in
| the tens of Mhz for some 1 Watt red LEDs. This is for my wife
| -- when she has a migraine she prefers very dim red light to
| complete darkness. In the Mhz range, there's no visible flicker
| by a longshot (although it costs a little more power). Most PWM
| systems I've seen that flicker, use lower-frequency signals.
|
| It must have been cool to play with LEDs in the 70s. We sort of
| take them for granted now, but they are so awesome. Truly we
| live in an age of wonders.
| WalterBright wrote:
| Thank you for the awesome reply!
| KennyBlanken wrote:
| It is widely known and has been utilized extensively for
| decades because the junction is more efficient when cool.
| Running it at a lower duty cycle allows for higher peak
| current/light output.
| derplerpmerp wrote:
| That's literally how LED drivers have worked for half a
| century.
| adrian_b wrote:
| In the now distant past, all manufacturers of electronic
| components published very extensive datasheets, application
| notes and user handbooks for all the devices that they were
| selling.
|
| One could typically learn much more electronics from the
| application notes or maintenance manuals of the vendors than
| from university courses.
|
| This included LEDs. For instance Hewlett-Packard published a
| good handbook for their LEDs, where many useful techniques for
| designing with LEDs were explained, including what you mention,
| that LEDs may have higher luminous efficiency at very high
| currents, so for achieving a given luminous flux you may save
| energy by operating them with pulsed currents.
|
| The use of multiplexing in the interfaces of multi-digit/multi-
| character LED displays (e.g for clocks or calculators) not only
| reduces the number of wires in the interface, but it also
| improves the energy efficiency, because only one
| digit/character is powered on, at a much higher current, but
| for a much shorter duration in comparison with a non-
| multiplexed display.
|
| During the golden era of electronics documentation, it could be
| difficult to get the vendor documentation, even if it was
| usually free, when you were located far away, e.g. in another
| country.
|
| When the Internet has appeared, for a short time it solved this
| problem so you could be located at the other end of the world
| and still access easily the datasheets, application notes and
| user manuals.
|
| Unfortunately, very soon after that, towards the end of the
| nineties and much more since 2000, the quality of technical
| documentation has degraded tremendously, so you now have easy
| access, but to much less useful information.
| ACCount36 wrote:
| Too many companies nowadays just straight up lock all
| relevant documentation behind a contract and an NDA.
|
| You want anything more than a 2 page marketing fluff piece?
| Talk to the sales! If you agree to a MOQ of 50000 and sign
| away your soul in a two miles long NDA, then you can have a
| look at the documentation. With one eye only. For a couple
| minutes.
| declan_roberts wrote:
| At this point I don't care about sustainable. I just want
| dimmable LEDs that don't flicker!
| quickthrowman wrote:
| Buy commercial fixtures or drivers with 0-10V dimming, problem
| solved.
| PantaloonFlames wrote:
| Is a driver something I can easily replace in an existing
| fixture?
| WaltPurvis wrote:
| This may be an erroneous and/or too simplistic answer, but I
| went through a couple rounds of using off-brand LEDs from
| Amazon in a chandelier, and they flickered badly when dimmed,
| then I finally ponied up a little more money and bought GE
| bulbs at Lowe's --- no flickering, ever.
| droopyEyelids wrote:
| Anyone else a bit uncomfortable with how they say this next
| generation will have lead in it, but we shouldn't worry about
| that?
| Jtsummers wrote:
| If you're not breaking them open and eating them you're
| probably fine.
| droopyEyelids wrote:
| They'll be mass produced in staggering quantities, discarded
| everywhere, and enter the ecosystem. Plus kids be chewing.
| NullPrefix wrote:
| Can these new LEDS do proper color spectrum or are we still stuck
| on incandescent bulbs?
| raron wrote:
| There are some with good color rendering (CRI over 95 - 98),
| but they are hard to find and much more expensive than the
| average LED light bulb (many doesn't even have their CRI
| specified so probably below 70).
|
| AFAIK None of them will ever have continuous spectrum (like the
| sun or incandescent bulbs), that's a limitation of the physics
| how they make light.
| netbioserror wrote:
| Never quite understood the color spectrum complaint, most of
| the incandescent bulbs I've ever seen are astoundingly red (low
| temperature), while I've always gotten the greatest color
| accuracy in my spaces from daylight-temp LEDs.
| umvi wrote:
| Now we just need modern houses that have a DC circuit dedicated
| to lighting
| quickthrowman wrote:
| This is an uneconomical idea, mostly due to voltage drop. In
| the commercial world, you can get 158 28-watt 2x4s on a single
| 277V 20A circuit using #12 wire.
| umvi wrote:
| So it's more economical to put a failure prone AC/DC
| converter into every single led bulb?
| econ wrote:
| I've bought 3 cheap alarm clocks and the LEDs are now so "good"
| the display lights up the entire room. With limited bedroom
| materials my inner macgyver was quite pleased with himself when
| he put one in a sock which has nothing to do with the topic but
| it did work. I can also confirm that cheap clocks are still
| amazingly hard to configure. By pressing multiple buttons
| simultaneously I managed to set one of the clocks to display the
| time only when a button is pressed. This is quite useless, I
| haven't figured out how to unset it and it isn't mentioned in the
| manual.
|
| My point would be that the LEDs are now so cheap and good that
| the rest of the devices seem expensive by comparison and
| manufacturing can't resist the urge to wrap them in crap. I think
| I've purchased 30 bicycle lights in total. The Edison bulbs with
| dynamo sometimes last a hundred years (except from the
| replaceable bulb)
| imp0cat wrote:
| You have to admit that even though some parts of the LED bike
| lights might be lacking, they are still pretty awesome compared
| to what was available when incadescent lights were the only
| option.
| econ wrote:
| Last two collect water inside the button. Can't switch them
| off. One more expensive set had the rubber casing peal off
| because the strap is gently pulling on it. My current
| expensive one had its button drop into the casing. I bring it
| inside now as it obviously can't get wet.
|
| The amount of light is great but we have a lot of "narrow"
| bike paths and people point them forwards blinding the
| opponent.
| PantaloonFlames wrote:
| Opponent! I like that. People riding in the other direction
| are opponents!
|
| For those who know English as a second language , opponent
| is a term used to describe the person you are competing
| against in a sports event, or fighting with, in a battle!
| rob74 wrote:
| > _We'd like to avoid the grave._
|
| Don't we all... but somehow I get the feeling that something was
| "lost in translation" here?
| jonathandramble wrote:
| No. Cradle to grave is a common term in life cycle analysis for
| products.
|
| https://www.eea.europa.eu/help/glossary/eea-glossary/cradle-...
| laserbeam wrote:
| Aren't perovskites incredibly fragile? I thought the reason they
| aren't used in solar panels is because they only last a couple
| years. Why should I believe LEDs made out if the same stuff would
| survive the test of time?
| ryukoposting wrote:
| To make a long story short:
|
| Perovskites are a particular physical structure that atoms can
| form together. It looks like a box made of one element, with one
| atom of another element inside inside the box. Perovskites are
| named after the naturally-occurring mineral that exhibits this
| structure.
|
| Mother Nature's Perovskite is made of Calcium and Titanium.
| Synthetic, flourescent perovskites are made of Lead and Cadmium.
| You can see the problem here.
|
| And yes, Lead is a massive problem even if the article downplays
| it somewhat. You can't put lead things outside, because rain will
| cause lead to leech into water supplies. That's bad.
| noqc wrote:
| leds are pretty small right? Typically encased glass? I don't
| think you've got much to worry about.
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