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?
rob74 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
And nobody keeps a logbook.
stephen_g 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
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.
fxtentacle 3 days ago [-]
"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.
They are a Chinese hardware manufacturer. The firmware source code appears to be open and on GitHub, but the hardware is fully closed. Accordingly, they are not "Open Source Hardware". They are not even "Source Available" on the hardware side.
thawawaycold 3 days ago [-]
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
ffsoftboiled 3 days ago [-]
“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 3 days ago [-]
Who are you quoting?
iancmceachern 3 days ago [-]
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 3 days ago [-]
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.
eternityforest 3 days ago [-]
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).
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 ;>
jononor 3 days ago [-]
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 3 days ago [-]
^ This answer outlines all the issues perfectly.
lm28469 3 days ago [-]
> 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 3 days ago [-]
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.
aziaziazi 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
I’d love to try that diagnostic mode but never eared of something like that. My machine is a recent Samsung (EU).
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 3 days ago [-]
That’s great thanks! Your post is in my favorites for future references.
Tomte 3 days ago [-]
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.
LargoLasskhyfv 3 days ago [-]
Could have Blutooth instead and cast it to your smartphone/watch, or whatever.
Think wireless JTAG for dummies/consumers.
Ray20 3 days ago [-]
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 3 days ago [-]
Something "being cheap" isn't really a reason to add it to a product.
ajsnigrutin 3 days ago [-]
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.
ACCount36 3 days ago [-]
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?
gosub100 3 days ago [-]
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.
piokoch 3 days ago [-]
"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.
mike50 3 days ago [-]
Dryers and microwave ovens do not require electronics. LED lamps with a wall wart that unplugs already exist.
mapt 3 days ago [-]
I'd imagine there are. In Shenzhen.
WalterBright 3 days ago [-]
The life of indoor LED bulbs has improved over the years. But I learned to only install them in vented fixtures.
zerocrates 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
Actually with fans specifically it has to do with legislation that requires them to not be able to mount a standard Edison bulb.
bfdm 3 days ago [-]
What? Why?
toast0 3 days ago [-]
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.
y33t 3 days ago [-]
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".
eru 8 hours ago [-]
Planned obsolescence only makes business sense, if you can be reasonably sure that the customer will buy from you again.
The home LED market is pretty fractured and there's not all that much brand loyalty. (At least at the lower level where companies churn out lowest cost LEDs. The companies that bet on brand loyalty tend to have somewhat better quality.)
pkolaczk 3 days ago [-]
Yes, even expensive Phillips LEDs heat up to 100 C. There is no way they could last the designed 50000h at that temp.
KennyBlanken 3 days ago [-]
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.
zdragnar 3 days ago [-]
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 3 days ago [-]
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.
eru 8 hours ago [-]
> Later on once the technology has matured this is less true.
It depends on the cost curve. When the technology has matured, the cheap ones might be good enough, too.
Eg approximately all tooth pastes are equally effective, so you might as well go with the cheapest one that agrees with your taste buds.
stevekemp 3 days ago [-]
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.)
NegativeLatency 3 days ago [-]
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 3 days ago [-]
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.
eru 8 hours ago [-]
Rapid flashing could also be a sign of using the wrong kind of dimmer for your LED.
pkolaczk 3 days ago [-]
I’ve had many expensive Philips or Osram bulbs failing.
mhb 3 days ago [-]
I have an original Philips EnduraLED that still works fine.
saturn8601 3 days ago [-]
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?
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.
saturn8601 3 days ago [-]
Wow, thank you for this resource!
superkuh 3 days ago [-]
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.
> 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.
Liftyee 3 days ago [-]
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?
eru 8 hours ago [-]
> Is there any way to avoid this problem besides regulation?
Just don't buy those, if you don't like them?
> 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??
That only works as a business if your customer comes back to you. The market for these dirt cheap devices is pretty fragmented. And people are unlikely to turn into repeat customers, if the previous gadget failed them miserably.
NegativeLatency 3 days ago [-]
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.
nottorp 3 days ago [-]
> 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 3 days ago [-]
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 3 days ago [-]
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...
3 days ago [-]
pjc50 3 days ago [-]
> - non replaceable batteries (flashlights)
Not encountered those? You people need to get onto Aliexpress where the good stuff that takes 18650 batteries is.
ilove_banh_mi 4 days ago [-]
"sustainable" was incorrectly translated from the Swedish "miljövänliga" which instead means "environmentally-friendly" ("sustainable" is "hållbar" in Swedish)
SoftTalker 4 days ago [-]
It's a marketing term anyway, it doesn't mean anything.
KennyBlanken 3 days ago [-]
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
joseppudev 3 days ago [-]
[dead]
4 days ago [-]
etiam 3 days ago [-]
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)
userbinator 3 days ago [-]
Whenever I see "sustainable" these days, I think "they must mean sustainable profit --- due to planned obsolescence".
hunter2_ 3 days ago [-]
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.
WalterBright 3 days ago [-]
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.
Saigonautica 3 days ago [-]
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.
eru 8 hours ago [-]
> It's used for lots of interesting things, such as temperature control, motor control and positioning, and LED lighting.
A pretty slow version of this is used in your microwave or airfryer. But they typically use a temperature sense (like a bimetallic strip) to turn the heating parts on for at least a few seconds and then turn it off again; they don't use a timer.
Microwaves never cease to amaze me. If I were in some alternate timeline where they weren't ubiquitous, and you told me such a thing would soon be in everyone's homes, there's no way I would believe you.
I mean, people putting their foods in a Faraday cage and then pointing a cavity magnetron at them to cook them? It sort of sounds far-fetched.
Bimetallic strips are also so awesome. Every time I hear that little 'click' noise, I think about them.
Is there a term for knowing just enough about the technology that underlies daily life, that you feel mildly absurd using it for mundane tasks?
3 days ago [-]
WalterBright 3 days ago [-]
Thank you for the awesome reply!
adrian_b 3 days ago [-]
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 3 days ago [-]
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.
throitallaway 3 days ago [-]
PWM. This is widely used method for dimming.
notfed 3 days ago [-]
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/
bjoli 3 days ago [-]
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 sjöss is actually quite crazy. The 30w had some issues)
eru 8 hours ago [-]
Yes, I get those as well from some cheap LEDs. Though if you flicker LEDs fast enough, it's fine.
WalterBright 3 days ago [-]
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.
Piezoid 3 days ago [-]
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.
KennyBlanken 3 days ago [-]
That's DLP and it's because DLP uses a color wheel at 3x the frame rate.
toast0 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
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.
CarVac 2 days ago [-]
Ah, those are just wider-gamut conventional projectors.
globular-toast 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
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.
WalterBright 3 days ago [-]
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.
hunter2_ 3 days ago [-]
How could the same modulation achieve "dimming" and "fully bright" simultaneously?
gizmo686 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
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
codebje 3 days ago [-]
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 3 days ago [-]
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.
jfim 3 days ago [-]
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.
mrheosuper 3 days ago [-]
you dont. But your eyes perceive brightness non-linear, which means to your eye, 80% of brightness is very close to 100%
3 days ago [-]
metaphor 3 days ago [-]
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 3 days ago [-]
Probably no longer true; patents only last 20 years.
metaphor 3 days ago [-]
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.
sneak 3 days ago [-]
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 3 days ago [-]
He's not talking about dimming. He's talking about the perceived brightness when you look directly at an indicator LED.
WalterBright 3 days ago [-]
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 3 days ago [-]
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.
ioseph 3 days ago [-]
I thought this was very common knowledge, we used the technique in our first year EE project.
3 days ago [-]
derplerpmerp 3 days ago [-]
That’s literally how LED drivers have worked for half a century.
KennyBlanken 3 days ago [-]
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.
WalterBright 3 days ago [-]
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 3 days ago [-]
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.
nefarious_ends 3 days ago [-]
This is why I love HN! Only here you’ll find the actual guy who invented dimming!
WalterBright 3 days ago [-]
I should have patented it! Mwuhahahaha
AnimalMuppet 3 days ago [-]
Nominative determinism strikes again! (Or is this anti-determinism?)
econ 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
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 3 days ago [-]
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!
NullPrefix 3 days ago [-]
Can these new LEDS do proper color spectrum or are we still stuck on incandescent bulbs?
raron 3 days ago [-]
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 3 days ago [-]
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.
Note that extending the lifetime is key to taking advantage of their lower base material cost. Lot of work needed there.
ryukoposting 3 days ago [-]
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 3 days ago [-]
leds are pretty small right? Typically encased glass? I don't think you've got much to worry about.
laserbeam 3 days ago [-]
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?
declan_roberts 3 days ago [-]
At this point I don't care about sustainable. I just want dimmable LEDs that don't flicker!
WaltPurvis 3 days ago [-]
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.
quickthrowman 3 days ago [-]
Buy commercial fixtures or drivers with 0-10V dimming, problem solved.
PantaloonFlames 3 days ago [-]
Is a driver something I can easily replace in an existing fixture?
baggy_trough 8 hours ago [-]
I don't think there are any light bulbs in my house that I have replaced more often than the LED bulbs, probably by a factor of 5x.
- light quality, especially years ago, was much too harsh. Color is still just barely tolerable for certain bulb types.
- inability to dim without flickering
- random burnouts (wasn't this supposed to take 10 years at least?)
rob74 3 days ago [-]
> 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 3 days ago [-]
No. Cradle to grave is a common term in life cycle analysis for products.
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 3 days ago [-]
If you're not breaking them open and eating them you're probably fine.
droopyEyelids 3 days ago [-]
They’ll be mass produced in staggering quantities, discarded everywhere, and enter the ecosystem. Plus kids be chewing.
3 days ago [-]
3 days ago [-]
opwieurposiu 4 days ago [-]
Is the gold in LEDs just in the bond wires?
lightedman 3 days ago [-]
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.
umvi 3 days ago [-]
Now we just need modern houses that have a DC circuit dedicated to lighting
quickthrowman 3 days ago [-]
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 3 days ago [-]
So it's more economical to put a failure prone AC/DC converter into every single led bulb?
quickthrowman 2 days ago [-]
No, it’s more economical to use a fixture with built in LEDs and an external LED driver that will last for 10 years.
baybal2 3 days ago [-]
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temptemptemp111 3 days ago [-]
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hulitu 7 days ago [-]
> Next generation LEDs are cheap and sustainable
Sustainable ? Made from tropical forest trees ?
ForTheKidz 4 days ago [-]
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."
Rendered at 11:25:04 GMT+0000 (Coordinated Universal Time) with Vercel.
- 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?
Also it's a good exercise in making sure the electrical panel is labeled correctly. Ours was somehow only labeled like 75% correctly.
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.
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.
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.
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.
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 ;>
The real question is do we even need displays for those? A few buttons and a knob is all we need
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.
They also document the error codes:
https://www.samsung.com/us/support/troubleshoot/TSG10000997/...
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.
Think wireless JTAG for dummies/consumers.
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.
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?
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.
They don't care if bulbs are replaceable, since their lifetime is limited to build -> sell.
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.
The home LED market is pretty fractured and there's not all that much brand loyalty. (At least at the lower level where companies churn out lowest cost LEDs. The companies that bet on brand loyalty tend to have somewhat better quality.)
Everyone I know who complains about LED bulbs failing, you ask them and they admit to buying the cheapest ones they could find.
At that point, I decided to just buy the cheap ones because that was easier than dealing with the warranty process anyway.
It depends on the cost curve. When the technology has matured, the cheap ones might be good enough, too.
Eg approximately all tooth pastes are equally effective, so you might as well go with the cheapest one that agrees with your taste buds.
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.)
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?
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.
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.
> 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.
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?
Just don't buy those, if you don't like them?
> 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??
That only works as a business if your customer comes back to you. The market for these dirt cheap devices is pretty fragmented. And people are unlikely to turn into repeat customers, if the previous gadget failed them miserably.
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.
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...
Not encountered those? You people need to get onto Aliexpress where the good stuff that takes 18650 batteries is.
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
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)
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.
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.
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.
A pretty slow version of this is used in your microwave or airfryer. But they typically use a temperature sense (like a bimetallic strip) to turn the heating parts on for at least a few seconds and then turn it off again; they don't use a timer.
This is known as bang-bang control.
https://en.wikipedia.org/wiki/Bang%E2%80%93bang_control
I mean, people putting their foods in a Faraday cage and then pointing a cavity magnetron at them to cook them? It sort of sounds far-fetched.
Bimetallic strips are also so awesome. Every time I hear that little 'click' noise, I think about them.
Is there a term for knowing just enough about the technology that underlies daily life, that you feel mildly absurd using it for mundane tasks?
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.
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.
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 sjöss is actually quite crazy. The 30w had some issues)
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.
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.
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.
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.
If the cycling of the light on and off is done at say 10kHz it's perceived as a dim light.
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.
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).
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.
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)
The amount of light is great but we have a lot of "narrow" bike paths and people point them forwards blinding the opponent.
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!
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.
Note that extending the lifetime is key to taking advantage of their lower base material cost. Lot of work needed there.
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.
Don't we all... but somehow I get the feeling that something was "lost in translation" here?
https://www.eea.europa.eu/help/glossary/eea-glossary/cradle-...
Sustainable ? Made from tropical forest trees ?