New ideas for dimming method for the LED Bulb - Page 1
Forum section: electronics / projects

author: WeiZhao
author_rank: Contributor
timestamp: July 30, 2021, 07:02:17 am
content: Hi, everyone. I've just joined in this forum.The LED BULB has developed for more than 8 years. As an EE, we also seeking for some new/innovation features such as let the products support 'Wi-Fi' 'Blue Tooth' 'Infrared Control' 'Motion Detect' 'Light Detect' 'NFC' 'Touch Control' 'Temperature Control' 'Vibration Control' …It seems all the features have been made out…So, would you help to recommend some new features for the LED BULB? New topology, dimming method?

author: Zero999
author_rank: Super Contributor
timestamp: July 30, 2021, 09:50:12 am
content: I don't want any crappy Internet features in an LED lamp. It would be very good to be able to buy a lamp with a very high relliability and efficiency, like the Dubai lamp.If it's going to have dimming, then it musn't be an LED reterofit lamp. Again as above, the lamp should be high reliability and efficiency. Ideally the installation should last for over 10 years, whilst maintaining >90% of the intial brightness. It should be nice and bright, with a full power setting of 5000 lumens, so I can use it for work. The dimmer control should be something fairly cheap and widely available, such as a potentiometer. No wi-fi, touch control, app, or any other rubbish.Colour temperature control is handy, but I don't see the need to have a separate control for that. The lamp could have high colour temperature such as 5000k when set to 5000 lumens, going down to 3000k, when dimmed to 1000 lumens and 2000k at 250 lumens. That way I can have a high colour temperature, when it's bright and I want to stay awake and a soft, warm light, in the evening, before I go to bed.I'd rather have a high quality product, with low running costs, rather than most of the consumer crap pushed nowadays.

author: Berni
author_rank: Super Contributor
timestamp: July 30, 2021, 09:58:32 am
content: Im with Zero999 here.All i want is a reliable high efficiency bulb with minimal electronics. Much like those Phillips Dubai LED lamps that run twice the LEDs at half the max power.Only problem is that consumers don't tend to buy these lamps because it costs twice as much as a regular cheap crappy bulb. So manufacturers don't have an incentive to make such high quality bulbs.

author: Terry Bites
author_rank: Super Contributor
timestamp: July 30, 2021, 11:26:51 am
content: If it switches on and off and has a good colour temperature I am happy.Life's too short for all this tech twiddle.Like hive for people who cant use a thermostat!

author: jonpaul
author_rank: Super Contributor
timestamp: July 30, 2021, 11:44:38 am
content: I want NO NEW "features" to fail.JUST RELIABLE LIGHT HIGH EFFICIENCY NOT JUNKj

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: July 30, 2021, 03:22:47 pm
content: 150W equivalent bulbs are what I like best. 5000K is a requirement and a high CRI is very desirable. Reliable- most bulbs never reach the advertised life. I don't want any other stupid features. I don't want it talking to my phone, the internet or the dog. It has one job, being a light source, and it should do that well.

author: emece67
author_rank: Frequent Contributor
timestamp: July 30, 2021, 03:24:33 pm
content: .

author: Miti
author_rank: Super Contributor
timestamp: July 30, 2021, 04:01:07 pm
content: Quote from: emece67 on July 30, 2021, 03:24:33 pmYes, I agree, that would be a nice feature. I just had a Noma bulb failing couple of weeks ago. It was bought during a promotional sale from Canadian Tire, three for $1.99 IIRC. I opened it to satisfy my curiosity and check out what I found. I resoldered all the cracks with lead free solder, very hard because the substrate is aluminum, but it’s back to life. Of course it’s not safe to use anymore, but I wanted to see if there’s anything else wrong with it. Nope, only the cracked solder in multiple locations.

author: jonpaul
author_rank: Super Contributor
timestamp: July 30, 2021, 05:41:42 pm
content: We use Sylvana Lighting (Belgium) and Phillips (Netherlands) for fine quality, life and performance.Costs more, but you get what you pay for.The knockoffs have only one priority: Cheapest possible design and parts, get your money and they care less.DONT BUY JUNKj

author: Gyro
author_rank: Super Contributor
timestamp: July 30, 2021, 06:00:18 pm
content: Quote from: jonpaul on July 30, 2021, 05:41:42 pmAs witnessed first hand, and by other people, Philips lamps (made by Signify) is developing a very poor reliability reputation.At the same time LEDVANCE, owners of theSylvaniaand Osram brand names, seem to he holding up well, at least at the moment. LEDVANCE, whilst currently using German engineers, is owned by a Chinese consortium.https://www.eevblog.com/forum/chat/electronics-products-where-are-they-madedesigned/msg3613396/#msg3613396EDIT: From the Sylvania website...QuoteNot quite sure how that ties in with LEDVANCE's use of the Sylvania brand name, but either way, they're Chinese owned.

author: jonpaul
author_rank: Super Contributor
timestamp: July 30, 2021, 06:14:18 pm
content: Sylvana is indeed owned by Chinese but has production based also in Germany and other countries.Sylvania Lighting R&D is in Belgium and refined to a very high level.Jon

author: TimNJ
author_rank: Super Contributor
timestamp: July 30, 2021, 06:26:55 pm
content: A bit wild to be flagrantly shitting on Chinese engineering/manufacturing, especially when the original poster is Chinese, don't you think? Not a very warm welcome to the forum.Wei Zhao, welcome to the forum.

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2021, 08:41:16 pm
content: Changing the color temperature is rarely needed, but depending on the application there are two normal choices:A. Roughly 5000 K--this is considered to be sunlight color. Probably better for a working environment.B. Roughly 2600 to 3200 K--this is considered to be "tungsten" color, i.e. the color of an incandescent lamp. This is often called "warm", even if the actual color (black-body equivalent) temperature (redder) is less than the "cool" (bluer) color temperature of the sunlight.

author: Gyro
author_rank: Super Contributor
timestamp: July 30, 2021, 08:55:26 pm
content: Quote from: TimFox on July 30, 2021, 08:41:16 pmNah, too blue, you'll keep the staff awake.[Edit: Actually most commercial fluorescent tubes probably are in the 5000k range]QuoteI think the world will probably get used to something like 4000k as a good comfortable compromise in this post Tungsten age. It must be abitlike how it was in the transition from the old candles, oil lamps and gas mantles to the great new era of electric lighting (although carbon filaments were pretty yellow).

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2021, 09:01:03 pm
content: Where this question becomes important is judging colors--matching ones tie to ones socks. However, it has been shown that matching (as opposed to judging) colors works well over a range of color temperatures, so long as the spectra are continuous. Of course, color balance is important to color photography (both film and digital). I made a beautiful large-format detail shot of a steam locomotive in an indoor museum, shot on EPY (3200 K balanced Ektachrome--we shall not see its like again), using tungsten photo lighting, where there are a few specular reflections from a skylight that are rendered blue in the image (which I tell people I did on purpose).

author: BrokenYugo
author_rank: Super Contributor
timestamp: July 31, 2021, 12:36:26 am
content: Seems to me most of the problems are thermal, which come from safely and cheaply cramming 800+ lumens of LED and driver into the A19 shaped package. Can't really do better without spending more (e.g. isolated driver design and exposed metal heatsink) or abandoning a 130 year old standard.

author: jonpaul
author_rank: Super Contributor
timestamp: July 31, 2021, 12:50:15 am
content: Colorimitery is a big topic.Lighting industry has evolved,2700-3400 K LEDs are common for "tungsten" color warm white.For Daylight Sun is 5600K, many LEDs are at 4000-5000KJon

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 31, 2021, 12:56:33 am
content: If the dimming and remote control is done over Wifi, make it usable without the cloud and document the protocol.

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 01:24:17 am
content: Quote from: Zero999 on July 30, 2021, 09:50:12 amHi, Buddy.This is my 1st post in this forum. I never thought will get so many replies. Really appreciated.Back to the topic, I fully agree with your opinion"Long Life Time""High Efficiency""Color Temperature""Low Running Cost"Thanks for your professional suggestions, man.I'll talk with our product manager, let's keep these features as the critical to quality. Others are really nice to have.

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 01:32:16 am
content: Quote from: Berni on July 30, 2021, 09:58:32 amHi, Berni.Thanks for your reply.Well, actually, I'm working for Philips Lighting. Really appreciated you like Dubai Lamp.We'll keep on digging the margin to improve the Lamp's efficiency.

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 01:35:07 am
content: Quote from: Terry Bites on July 30, 2021, 11:26:51 amCopy, Terry.Switching on/off to change the Color Temperature.This is quite a useful feature, and I thought we've already have some products.Thanks.

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 01:37:52 am
content: Quote from: jonpaul on July 30, 2021, 11:44:38 amCopy that.merci~~

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 01:40:49 am
content: Quote from: Conrad Hoffman on July 30, 2021, 03:22:47 pmHi, Conrad.Higher Lux, Higher CRI, qualified lifetime, copy.BTW, say hello for me to your dog.

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 01:45:53 am
content: Quote from: Miti on July 30, 2021, 04:01:07 pmHi, Miti.You're quite professional!RELIABILITY, always is key to customers.

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 01:56:10 am
content: Quote from: jonpaul on July 30, 2021, 05:41:42 pmHi, Jonpal:Thanks for choose Philips Products.Trust me, we have the best quality in LED LAMPs' marketing.For we are doing the most complex and comprehensive tests for the products.

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 02:12:02 am
content: Quote from: Gyro on July 30, 2021, 06:00:18 pmHi, Gyro:Thanks for your reply.Actually, I'm working for Philips Lighting more than 15years. Focusing on SMPS， first for fluorescent lamps, then for led lamps, now for led bulbs.Now Philips Lighting has changed name to Signify.As you mentioned 'As witnessed first hand,Philips lamps (made by Signify) is developing a very poor reliability reputation.'...Would you illustrated more details, like products names or failure mode ?Still, I trust the product from Philips is famous for it's quality.

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 02:29:12 am
content: Quote from: TimNJ on July 30, 2021, 06:26:55 pmHi, Tim.Really appreciated to join this forum.As I've introduced myself before: After I've got the EE bachelor degree, I joined Philips Lighting Global Development Center.Which is the world lead for the SMPS. And Philips trained me how to made a product with the world class reliability. Philips has the most critical and complex test for the product. So, just I've stepped out the university, I've learnt the most standard&formal ways to develop a new product.Besides, I've also join a local Chinese company also developing the LED drivers.Frankly speaking, they only perform 1/10 tests for the drivers, especially neglect the high temperature reliability/long life time tests...Even, if the LED driver can bright the lamps, then is can sell to costumers...Honestly, it still has long way to go for local Chinese companies. But I believe this situation is changing. Now the marketing is becoming more and more clear ,if the products always has huge custom complains/failure return, the reputation of the company will broken.But thanks anyway for pointing out this problem

author: themadhippy
author_rank: Super Contributor
timestamp: July 31, 2021, 02:32:30 am
content: QuoteYou might want to contact dave saveryhttps://youtu.be/4LZsTkaWONo?t=358

author: TimNJ
author_rank: Super Contributor
timestamp: July 31, 2021, 03:42:26 am
content: Just some thoughts...I think there will always be some bias if you ask engineers what they want in a lightbulb compared to if you asked the same question to normal consumers. I think the engineering mindset naturally wants to prioritize reliability.And my guess is that an older demographic (let's say people 40-50 years and older), will gravitate towards simple (nothing fancy) lighting, while younger people may be more interested in "high-tech" features like WiFi, etc. Of course, I think ~all~ people want and expect their lightbulb to last a long time, but it may not be their first thought when choosing a lightbulb.On this forum, I am not sure of the exact demographic, but I think it is mostly older engineers, so the responses you get may, in some way, reflect that. (Sorry to generalize so much, everyone.)-----That said...1. I fully agree that reliability should have higher priority. Perhaps you can offer a really excellent and "no questions asked" warranty, something beyond industry normal, say 7-10 years. This shows the customer that you are taking reliability seriously. And if the bulb is built well, it should really be no problem. Allow some space for a properly sized electrolytic cap, maybe add potting compound to an aluminum base (like the old Cree bulbs used to be made), and I think it will last a very long time. And try to avoid hand soldering in the assembly process, especially if you are using an aluminum core PCB. I Way too many defects due to cold solder joints on these heat-sinking PCBs.2. One feature I wish my light bulbs could have (without buying a $50 USD Philips Hue) is to automatically shift the color temperature to match the time of day. I use "f.lux" on my PC and I can tune the average color temperature of my monitor at different times of the day. I know scientific research has shown it's best to stay away from blue colored light late at night. For example, I would change all my bulbs in my bedroom and office room to this type if they were not so expensive like Philips Hue. I could probably justify spending $15 USD/bulb for this feature.The technical hurdles are challenging (to do inexpensively)...How will the bulb know where it is on the planet? How does it know what time it is? A few quick thoughts: It could have some sort of NFC, IR, or some other crude communication interface interface which could program its location and time/date once...but then you need a RTC in the bulb, and I think that's probably a bad idea since I would not suggest putting a battery inside a blazing hot lightbulb. Another idea is to use powerline communication and some centralized hub that plugs into an outlet in your house. But then you need some magnetics and other bulky components to sense that signal. Finally, I wondered if you could use the atomic clock signal that many countries have, i.e. US in Texas (I think) and I think there are a few in China too. But that's never going to be so reliable, and you probably still need to have an RTC + battery.Honestly, the cheapest/simplest solution to getting communication to a bulb is probably....WiFi or Bluetooth, especially given the low cost nRF chipsets that exist now, as much as I wish that wasn't true.So, really I've got no good ideas on that, but I do wish that I could just screw in a light bulb and it would automatically change the color temperature perfectly, to match the time and my location. But, I think it's not so simple!

author: james_s
author_rank: Super Contributor
timestamp: July 31, 2021, 06:00:33 am
content: I have quite a few Philips Hue lamps now and have been really happy with them. They make a variable color temperature bulb that is nice because it goes down to about 2200k which is much wamer than most of the variable CCT lamps that only go down to 2700k. The cost is a bit high but so far I've never had one fail so they're a reasonable value to me. The only thing I don't like is they use PWM dimming that is only about 1kHz and I can see the flicker if I scan my eyes.Important to me: High CRI, good dimming from full brightness down to barely glowing, nice to have variable CCT down to at least 2200k and high PWM frequency or even better, analog dimming that doesn't use PWM at all. Long life and high efficiency.

author: Gyro
author_rank: Super Contributor
timestamp: July 31, 2021, 09:28:25 am
content: Quote from: WeiZhao on July 31, 2021, 02:12:02 amThe failure mode is quite simple, a single LED failure out takes out the whole lamp - you are either over-driving the LEDs, using poor quality ones, or not cooling them sufficiently. As I indicated it the other thread that I linked. Ihadone Philips LED lamp in the whole house, the rest being ordinary supermarket / DIY store brands. It was the newest by a good margin and has been the only one to fail.Failure mode is initially flickering and then total failure, opening up reveals one smd LED failed with brown burn marks in the phosphor (arcing across detached bond wire) indicating significant volt. As an experiment I bypassed that LED (you're driving them with constant current, right?). A few weeks later, it failed again with another burned LED, same appearance.Failure on single LED burn-out it exactly the same symptom as David Savery reported in is video, showing many failed Philips downlights, and as reported by others.The lamp construction includes aluminium plate and internal 'cone' with thermal compound. For the LEDs to be failing open circuit, you must either be using really shite LEDs, or driving them so hard that you burn out their bond wire connections. Despite being in an open fitting, I found the lamp far too hot to touch.Lamp details as follows:13W 2700k 1521lm 115mA220-240Vac 50/60HzMade in China <17E99290012341CPhilips Lighting, IBRS 10461, 5600 VB, NLCE EACIt will probably won't ease your pain to know that my personal experience was that Philips brand CCFLs failed earlier than supermarket brands too. Sudden failures, not degraded output.EDIT:QuoteYes, that's what the guy from Signify said in the voicemail he left for David Savery. What is the owner of a failed, just out of warranty, Philips lamp supposed to do with that?Complacency comes before a fall.

author: jonpaul
author_rank: Super Contributor
timestamp: July 31, 2021, 10:05:10 am
content: Rebonjour a tous...en particular WeiZhao!1/ Felio Sylvania was only for a few years, there was alo an Indian owner before the current Chinese ownership. It is now just Sylvania Lighting.2/ Visited Philips in Eindhoven in 1980s, you could see the history of the earliest lamps, and the glass oven to make them.3/ LED change color balance tungsten/daylight is possible.4/ Thousands of patents cover the technology of ballasts, PFC, color control, and lamp design. A search of patents is a good way to begin research for any proposed improvement.5/ Failure rates depend on component derating, ambient T, number of single failure parts, etc. The mains transients, heat in a fixture and duty cycles make lamp electronics a reliability issue in general.6/ So a complex control system, with RF comm, and many features will fail sooner than a plain old lamp.7/ Dimming by external existing dimmers eg triacs is a huge issue for LED lamps, many exhibit poor dimming behavior. Special ballasts are needed.8/ Your title is not exact as the "dimming method" is a power control and you mean (I think) remote control or control systems that drive the dimmer.Hope this is of interest,JonPS: to WeiZhao, do you know our friends at Syl Belgium?

author: Marco
author_rank: Super Contributor
timestamp: July 31, 2021, 11:46:16 am
content: A big manufacturer could get some reputation by running a program which gives them some proper incentive to meet their warranty. Partner with major stores (such as walmart in the US) to give them test sockets for your led bulb, if bulb failed within warranty period the store gives you the closest replacement no questions asked (don't start with x hours a day bullshit).Having to deal with postage for a small ticket item warranty is a non starter.

author: WeiZhao
author_rank: Contributor
timestamp: July 31, 2021, 11:56:53 pm
content: Quote from: jonpaul on July 31, 2021, 10:05:10 amHi, Jean:Ni Hao Ma?Well, your name is same as our general manager.What a pity, I don't know any friend from Syl in Belgium.1. Searching the patent and then to make any improvement/innovation is a very good suggestion, I will search more patent.2. Now most customers are still using Triac Dimmer from LUTRON. So our products developed are still required to compatible with exist Triac Dimmer.3. For my title , yes , a bitter limitation. My first thought is to gather some new ideas on the led bulb.Thanks.

author: WeiZhao
author_rank: Contributor
timestamp: August 01, 2021, 12:13:37 am
content: Quote from: Gyro on July 31, 2021, 09:28:25 amHi, Gyro:As you mentioned the driver is a constant flow source, won't general peak voltage to damage the SMD LED。The problem could be L2 SMD to Aluminium insulation weakness also could be the driver pump out too high current...Thanks for your detail description.

author: WeiZhao
author_rank: Contributor
timestamp: August 01, 2021, 12:58:23 am
content: Quote from: TimNJ on July 31, 2021, 03:42:26 amHi Tim:For me, the elder engineers are treasure, they have abundant experiences in this area.Unlike the Software, the computer languages are developing all the time.For hardware, we are still using the typical topologies, I'm still learning Erickson'sFundamental of Power Electronics.Your suggestion is really constructive. Now most products are adjusting the lighting by using sensor to detect the ambient light .Changing the color temperature by timing inside the bulb is interesting.Also, the critical point is how to let the bulb know the exactly time outside?1. Wi-Fi, Blue Tooth, NFC can achieve, but cost increased and too luxury2. After power off , the timing still need to work3. How to distinguish different time zoneI'll gathering more information in these days.

author: RJSV
author_rank: Super Contributor
timestamp: August 01, 2021, 03:02:02 am
content: Just curious, off the wall question, thanks. Oh and Welcome to eeVblog forum!So, an EE working on lighting at Phillips: Does an Engineer there do any involvement with 'optical coatings' or similar features, or just mainly circuits and components?Just curious, watching advancements in LED tech...- Rick B.

author: jonpaul
author_rank: Super Contributor
timestamp: August 01, 2021, 10:42:44 am
content: WeiZhao Rebonjour,Many LED failures seem to be in the PFC/line side, perhaps due to mains transients.The recertifier and switch transistors are most critical.The lamp sockets are sometimes failing adhesive/frit with age and heat.We used the best electrolytic decades ago when I designed HID electronic ballasts, class 135, specially designed for ballast use.Varying CT is unneeded cost and complication in 90% of uses.Light Radiation pattern is often an issue with very bad intensity in some directions of most screw in LEDs.An incandescent lamp is almost omnidirectional.Finally the mechanical robustness, in a vibration area or during shipping.Just a few thoughts,Jon

author: WeiZhao
author_rank: Contributor
timestamp: August 02, 2021, 01:02:45 am
content: Quote from: RJHayward on August 01, 2021, 03:02:02 amHi， HaywardFor me, I still focus on the electronic parts. For the coating or phosphor we don't involve very deeply.Actually another guy who will take care. The is way of working in big company.But the information is available if the engineer is interested in this area.

author: RJSV
author_rank: Super Contributor
timestamp: August 02, 2021, 03:01:48 am
content: WeiZhao:Thank you for question about optical aspects.Now, I have info on a partial solution, maybe helpful:For control access to 12 Volt Garden lights, and having no usual switches, etc there are products that tell time, er...actually they assume, when power is applied, that it is dusk: maybe 7 pm.That is enough information for the low-voltage lamp, to start timing cycles, in that case the lamp stays lit for a time of four hours. Of course, in the Phillips case, the customer wants to use (wall) switch...not to just leave switched on forever, or perhaps duct-taped over: that part is not so attractive. But the method DOES establish a 24 hour cycle, while the software counts out that fixed real-time run, for an outdoor light.If you could, somehow (?), have customer use an out of the way switch, you have solved part way.(I wonder how, in other languages, the term :'Out of the way switch's gets interpreted? )Auto-translate software can sometimes have hilarious results, LOL.Anyway, by leaving the bulb power 'ON' plus the fact that you apply power at 7 pm, 9 pm etc as you choosethat gets the bulb on 24 hour known TIME.How about NO switch, just using breaker switch, although thats an uggh ---funky and potentially unsafe method, plus that would re-initialize EVERY smart bulb but that might be OK. (?)

author: Monkeh
author_rank: Super Contributor
timestamp: August 02, 2021, 03:06:08 am
content: Quote from: RJHayward on August 02, 2021, 03:01:48 amThis is wholly impractical as you'd have to replace every lampholder with one with three contacts.

author: jonpaul
author_rank: Super Contributor
timestamp: August 02, 2021, 03:13:31 am
content: Market Research note:Fine feedback on this forum, but we are electronic folks, and not the market you may address!Suggest that Phillips employ real market research on what features or characteristics the target market desires.It is costly and not free. Generally you get what you pay for.Jon

author: RJSV
author_rank: Super Contributor
timestamp: August 02, 2021, 05:49:03 am
content: Monkeh:I'm only suggesting, one partial solution. The 'garden' lights utilize your turning ON (the low voltage battery power) the time is always assumed to be 6 pm, for example, and you then leave that backyard light 'ON', with the lamp circuit having the real-time clock, within it's processor. The lamp circuit does the switching, in that case using a scheduled 6 pm ON time, and 10 pm OFF time.So, in the 'mains powered' case, a simple wall plug-in would be able to 'self-switch', meanwhile consuming the few milliwatts for real time clock, in the MCU, there.The other features can be placed in the device also, sensors adjusting LED apparent optical temperature.(If I got the right terms, for light emission)

author: WeiZhao
author_rank: Contributor
timestamp: August 02, 2021, 08:05:18 am
content: Quote from: TimNJ on July 31, 2021, 03:42:26 amHi, Tim:I've discussed this idea with my colleagues, this is a brand new idea for bulb.But also the most difficulty is how to tell the bulb the time.1. RTC need an extra power supply...2. Use low frequency radio to sense the time, the feed back is signal weak after setup in the building...3. As you mentioned, receive from GNSS satellite , but the receiver/decoder size and cost cannot accept...We'll continue discuss this topic.

author: jonpaul
author_rank: Super Contributor
timestamp: August 02, 2021, 10:30:26 am
content: WeiZhao: Search deeper, as the color changing bulb is perhaps NOT new idea and already in many patents.I propose a Simple fix for color changing lamp that works with NO web connection or time sync:Use the intensity of the room light, To color changePlace a tiny Lens and Photo diode near the lamp base pointing outwards to sense room light.Below a Lux threshold, warm white LED ONAbove a Lux light threshold, daylight LED ONto prevent stutter. optical filter ton photodiode, cut LED light freq, so IR or far blue can be used to sense. Use hysteresis as needed.Please Send me my patent royalties if it works out.Bon chance,JonWe could exchange our email on MP.

author: Zero999
author_rank: Super Contributor
timestamp: August 02, 2021, 10:34:05 am
content: Quote from: WeiZhao on August 02, 2021, 08:05:18 amI wouldn't worry about having an RTC, or sensing the time. People generally don't need a bright, low colour temperature, or dim high colour temperature light. Which is why I suggested dim to warm, i.e. reducing the colour temperature, along with the light output, to mimick natural light sources such as the sun.What sort of lamp is this going to be? Reterofit, i.e. a standard Edison Screw or bayonetor lamp, or a complete luminare?I'm not keen on dimmable reterofit LED lamps. The sort which use a standard phase control dimmer are hit an miss. The generally work, can flicker, especially if the dimmer doesn't have enough load. The kind which reuire Wi-Fi or a remote control dim reliably, but require connection to the Internet, or the remote can get lost.An LED luminare is much better. The dimmer control can be a cheap potentiometer, which is easy to replace and there's not connection to the Internet or remote control, to get lost. Quite often these types of fittings can be controlled with a 0V to 10V/5V analogue signal, which means they have the provision to be connected to a home automation system if needs be. The downsides are: higher upfront cost, it needs to be wired by a competant person and it's more difficult to replace, when it fails.

author: Marco
author_rank: Super Contributor
timestamp: August 02, 2021, 02:35:34 pm
content: Quote from: Zero999 on August 02, 2021, 10:34:05 amThey make dimmers specifically for LED lights though which are designed to work at low load.It's kinda sad using phase angle cut off at terrible PF as a signalling method for dimming LED lighting, but you can make it work reliably.

author: Zero999
author_rank: Super Contributor
timestamp: August 02, 2021, 03:29:17 pm
content: Quote from: Marco on August 02, 2021, 02:35:34 pmYes the problem is, dimmable reterofit LED lamps have to be designed to work off standard phase controllers, otherwise they'll get lots of returns from clueless consumers who don't know any better.

author: TimFox
author_rank: Super Contributor
timestamp: August 02, 2021, 05:40:06 pm
content: Or from customers who see no need to re-wire their dining room to replace the existing bulbs.

author: RJSV
author_rank: Super Contributor
timestamp: August 02, 2021, 07:15:13 pm
content: Here is more, regarding an LED BULB, having no serial interface (for setting timed (auto) daily cycles.In the picture, the low voltage bulb has the glass removed: You can see the little crystal, for the processor (encapsulated in black epoxy 'blob').Sorry about blurry photo.There are two LEDs on that little circuit board, for the 'candlelebra', supplied by two regular AA type batteries.

author: Zero999
author_rank: Super Contributor
timestamp: August 02, 2021, 07:16:55 pm
content: Quote from: TimFox on August 02, 2021, 05:40:06 pmIt shouldn't be that difficult to design a dimmable LED luminaire, which can be retrofitted to use standard UK wiring.The UK ceiling rose is wired like this.It wouldn't be hard to replace it with a different type of junction box, which permanently powers the lamp, with the switch going to an ADC input and pull-up current source. The switch could be replaced with a variable resistor, if dimming is required, or just left as is, if the dim function isn't used. The lamp would obviously need to have a very low standby power consumption: <1VA to be considered environmentally friendly.The only issue might be complying with the wiring regulations and as I don't have an up to date copy, I don't know if it would be allowed.

author: Marco
author_rank: Super Contributor
timestamp: August 02, 2021, 07:20:17 pm
content: Quote from: TimFox on August 02, 2021, 05:40:06 pmCalling swapping out a dimmer rewiring is a bit exaggerated.

author: RJSV
author_rank: Super Contributor
timestamp: August 02, 2021, 07:32:25 pm
content: Here is a second photo, of the drugstore 'garden light' that starts internal timer when batteries are installed.I bought at a local WALGREENS (no affiliations).I had been impressed at the clever angle taken, as this outdoor lamp has no interface. But it starts tracking time, internally, with assumption that consumer had done the install, just at dusk, and so the little device assumes, on its own, that it was '6 O'Clock PM'.Put that concept in with the rest of the good ideas here and you now have 'TIME'.It's maybe not pretty... (How light bulbs are made)....like the old joke about gross 'sausage making' factory.Using this method, might involve PATENT law...a subject I'm very sensitive about, being an Inventor/Engineer.By the way, I have not seen this 'self-timed Candlelebra' on sale for a couple of years.Drug Stores often carry some interesting TOYS to check out, as an ever-curious Inventor.- Rick B.

author: TimNJ
author_rank: Super Contributor
timestamp: August 02, 2021, 07:46:07 pm
content: Quote from: Zero999 on August 02, 2021, 10:34:05 amI agree with this approach, but how does the bulb have any concept of knowing what time it is in the first place?I like Jon Paul's idea..It sounds a little bit like the "pre-flash" for an automatic camera flash. i.e. the little stutter flash that happens a few 10's of milliseconds before the full power flash is applied during the exposure. The pre-flash is a constant lumen flash that bounces off the subject and back into the light sensor onboard the flash. The quantity of light detected by the sensor allows the camera to pick the proper flash setting for proper exposure.For these flashes, the light sensor needs to be positioned such that it is not fooled by the light coming from the flash itself. So usually, the flash bulb is at least a 10-15mm in front of the sensor. See Minolta Auto 200X flash attached. Anyway, just rambling, kind of irrelevant to this discussion.Perhaps the opposite could be adopted for this lightbulb. Every 15 minutes (or so), the bulb shuts off for a very short amount of time. During this off-time, the ambient light is detected. The wavelength and intensity shows whether it is day-time or nighttime. If using a microcontroller, perhaps a primitive machine-learning/neural network algorithm can be implemented which adjusts parameters based on each specific installation. The constants are stored in non-volatile memory. This may make it more flexible. Maybe unnecessary.I am sure with enough research, it could be done fairly reliably. In the case where the logic is unsure of the time of the day, perhaps it can have a default state, i.e. 3500K @ 800lm.

author: james_s
author_rank: Super Contributor
timestamp: August 03, 2021, 03:20:41 am
content: Quote from: TimNJ on July 31, 2021, 03:42:26 amThere is more than one Philips Hue. The "white and color ambiance" bulbs are RGB/CCT and cost close to $50 retail but they also make a "white ambiance" series that is white only but variable CCT from 2200k-6500k and those are only $20-$25. If you want even cheaper, Ikea has their Tradfri line which includes several different types of variable CCT lamps using Zigbee. They even offer a wireless remote so you can control a lamp directly without needing any kind of hub. Even cheaper than that, Home Depot's Ecosmart brand has a variable CCT lamp that does 2700k-6500k $9.99 for a 2-pack, I have a few and they work fine, although I prefer the Hue as it has a much wider CCT range and can be programmed to store its last state if power is lost.

author: james_s
author_rank: Super Contributor
timestamp: August 03, 2021, 03:25:59 am
content: Quote from: Marco on August 02, 2021, 07:20:17 pmIt may as well be for the average person. Most of us here are technical people, we would not hesitate to swap out a switch in our home and could do it properly and safely. For the average non-technical person though swapping out a switch (safely at least) means hiring an electrician or handyman and that's a significant hassle and expense.I don't know about the rest of the world outside of the UK but in the US there is no standard for the way switches are wired to lights. Sometimes you'll see the arrangement that seems to be standard in the UK where power comes directly into the light box and a separate switch drop runs from there to the switch. Other times power comes into the switch box and from there heads up to the light. Sometimes you see more complex situations where a single box contains two or more switches that control different lights, some fed from different circuits, some may be wired with power going straight to the light, others with power going straight to the box, some may be a middle "4-way" switch between a pair of 3-way switches, say on the entry landing of a split level house like mine. As I've discovered with my automation efforts, sometimes trying to do a non-wireless approach does require doing some significant rewiring.

author: Zero999
author_rank: Super Contributor
timestamp: August 03, 2021, 07:46:16 am
content: Quote from: TimNJ on August 02, 2021, 07:46:07 pmIt doesn't need to know. The user sets the brightness and the colour temperature is automatically adjusted. I don't want any fancy AI in a light bulb, even though it would be fun to design.

author: TimNJ
author_rank: Super Contributor
timestamp: August 03, 2021, 03:26:33 pm
content: Quote from: Zero999 on August 03, 2021, 07:46:16 amAre you talking about a bulb which automatically changes color temperature as it ismanuallydimmed from a wall-plate dimmer? Interestingly enough, many LEDs do this "naturally" already, i.e. at lower forward current, the color temperature goes down, but usually the shift is probably not much more than 500-750K, IIRC.I am talking about a bulb which after installation, automatically dims and/or changes color temperature in accordance with the time of day. i.e. At noon, 5000K, at dusk 3500K, at night 2200K, etc. I don't want any human intervention, no programming, no opening an app. So, the bulb itself needs some intelligence to determine when it is day and when it is night.As Jon Paul suggested, and may very well already exist(!), the bulb can have a light sensor (or two). The bulb can be shut off for a short amount of time, un-noticeably and periodically throughout the day, to make this ambient measurement. I think no need to be scared of 'AI' in this context. The learning algorithm I'm suggesting can probably be run on an 8051, since it will have 10's of minutes to process the data . Basically, depending on the environment, room X's night-time may look different than room Y's night-time. (i.e. In a city, perhaps a streetlight shines in the window at night, but on a farm there is total darkness.) Hard pre-programmed thresholds may give...unexpected results.Maybe I'm talking out my ass, I don't know. I kinda want to try now though!

author: james_s
author_rank: Super Contributor
timestamp: August 03, 2021, 11:59:47 pm
content: Quote from: Zero999 on August 03, 2021, 07:46:16 amThose have existed for years, the Philips 'Warm Glow' series. I have a handful of them I bought probably 5 years ago.https://www.usa.lighting.philips.com/consumer/choose-a-bulb/warm-glow-dimmable-led-lighting

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 04, 2021, 12:38:56 am
content: Just a thought here. I am an older guy, but like the wifi control features in lamps and use them regularly. One of the uses is to simulate habitation when I am away from home for a while. Most of the bulbs I have used have a "reliability" problem. If there is a brief power failure, or some types of glitches these bulbs come back on line in what seems to be a totally random state. Sometimes in the "program" mode. Sometimes in a flashing "fault" mode. Sometimes off and uncommunicative. This is not unique to bulbs. Many "smart" devices have these kinds of issues.I would really like a bulb that had a consistent behavior in the presence of unstable power. Preferably returning to the previous state. I know there are many issues with this, but that is what makes it an engineering problem worthy of attack.

author: james_s
author_rank: Super Contributor
timestamp: August 04, 2021, 01:34:30 am
content: A serious flaw with most "smart" bulbs is that they default to full brightness white light, so if you have a bunch of them around the house and you get a momentary power glitch, a common occurrence around here in the winter, all the lights come on full brightness. Lots of fun when it happens in the middle of the night as is often the case for storms. After the most recent firmware update the Philips Hue lamps let you configure the default state which is fantastic, I really don't know why others don't. Having it remain in the last used state unless you do something clearly deliberate like flip the light on and off 3 times in succession seems like the obvious thing to have it do.I have several different brands of zigbee bulbs in service but I'm not using any of the hubs, I just have a Conbee II stick plugged into my Raspberry Pi based Home Assistant server. It's a bit of work to set it up but once that's done it works the way all this smart home stuff ought to work, everything interoperates with everything else and cloud is totally optional.

author: Zero999
author_rank: Super Contributor
timestamp: August 04, 2021, 08:27:31 am
content: Quote from: TimNJ on August 03, 2021, 03:26:33 pmYes.QuoteI can't say I've noticed. It's easy to get a larger colour temperature shift by haing arrays of different colour temperature LEDs.QuoteNo doubt it's possible and would certainly be a fun project, but it isn't something I'd be interested in installing in my house. There's too much scope for it to go wrong. I'd rather have a simple, dumb manual control.

author: TimNJ
author_rank: Super Contributor
timestamp: August 04, 2021, 10:54:05 pm
content: Quote from: Zero999 on August 04, 2021, 08:27:31 amI agree that there are likely many many corner cases that could easily fool such a design. Given that the world seems to be going towards 'connected' everything anyway, trying to solve this issue in a non-connected way probably is for naught. I still like the idea of plugging something in and not having to touch it though.

author: TimFox
author_rank: Super Contributor
timestamp: August 04, 2021, 11:05:59 pm
content: There’s a difference between installing a novel system and replacing a bulb. “Replacing a light bulb” used to signify a simple process.

author: jonpaul
author_rank: Super Contributor
timestamp: August 05, 2021, 01:56:00 am
content: Rebonjiur, the post is confusing as the objective seems to be a LED "light bulb" rather than a fixure or luminarie.The screw in bulbs are now obselescent in exishtng homes and fixtures.Best efficiency is replacing the fixture.Scre in bulbs have very limited size, base etc.The OP should exactly define what he wants:A screw in bulb replacement?A controllable and highly efficient light fixture?Seem most of the thread is fixed on screw in bulbs.Jon

author: TimFox
author_rank: Super Contributor
timestamp: August 05, 2021, 02:29:32 am
content: Edison-base bulbs have been around for a while. Staying with a standard interface as the technology advances to new forms of light can be a sensible strategy for domestic purposes, rather than forcing consumers to change sockets when not truly necessary.

author: KalyanProdhan
author_rank: Newbie
timestamp: August 05, 2021, 05:24:38 am
content: Hi,I am an Govt. engineer, and philipswas(not is) our first choice. But in India, after taken over by signify, the quality was drastically going down. The 20 watt slim recessed lights installed in the very important seminar halls, meeting rooms, and in youth hostels are get blinked when any switching in the ceiling fan or even regulator function happens.While going through the driver circuit, I found absence of several parts in PCB. In this case, the filtering large capacitor, just after the rectifier, is absent, don't know, why, (causing reset of IC due to micro power surge)? Several times I found common mode chokes are replaced with single side drum inductor. Many times, the biasing resistances and electrolytic capacitors remain absent, reducing the life of the entire luminaire drastically.In retrofit T8 lamps, the two series resistance used in series of line & neutral, are of low wattage, and fails mostly. And in street light and high wattage lights, surge units are mostly compromised. I can send you the pictures of the failures, in lot, it's reason, reverse engineered. Later, insted of replacing a lot of fittings, we have to install separate surge unit, to use those fittings.An interesting fault was found that due to replacement of rubber gasket, with plastic gasket. The metal body enlarged in heat, but the optics are get cracked, as it was get stress, due to absence of rubber cushion in between screw and optics hole.In India at present, general publics are not want to pay more for philips, while they get failure even quicker than their local brand. Even us, the govt. officials, having the maximum inertia of thinking (As we cannot experiment more with public money), are changing.Sometime some rumers came in ear that great quantity was manufactured in india by it's dealers in their private workshop, to cope up with high surge of demand before Puja and March year ending. Surprisingly after inspection, when query is done from govt. officials or it's vendor, philips signify says it's their product, and then repair or replace later. I have the official documents, but cannot upload here without permission.If this is the quality of the our old beloved philips, sorry to say, PHILIPS dying...If you really want to know the differance of your design, and what we get in reality, you should purchase philipsproduct, from that country's store (may be online store), and test the differance.An visit to youth hostel in purulia, west bengal, I captured the video of blinking of philips light, with ceiling fan regulator changing.Here is the link. The language is in local language bengali, however, you will realise, the current status of your reputed brand in INDIA.https://youtu.be/8EwshMsoBkc

author: james_s
author_rank: Super Contributor
timestamp: August 05, 2021, 08:47:37 pm
content: Quote from: TimFox on August 05, 2021, 02:29:32 amTotally agree. I have mostly vintage fixtures in my 1970s house, I like them and modern ones would look totally wrong. Also having a reputation as a handy guy, I am frequently called over by family and friends to fix things and on several occasions I have had to replace integrated LED light fixtures that had failed. Even the most technologically inept person can change a light bulb, most people have to call an electrician or handyman to change a fixture. Initially creating a good screw-in LED lamp was a significant technological hurdle but now that problem is solved. The only reason there are so many low quality bulbs out there is that consumers are highly sensitive to price. If you buy the cheapest product you can find, whether a screw-in bulb or integrated fixture, it is likely to not last long. Integrated LEDs offer possibilities of entirely new fixture designs that were not possible with old fashioned light bulbs but for traditional styles screw-in retrofit lamps are arguably the best option, they are available in a plethora of varieties from basic 99c bulbs to expensive RGBW smart bulbs in a multitude of shapes and styles that all fit into a standard and ubiquitous socket.

author: themadhippy
author_rank: Super Contributor
timestamp: August 05, 2021, 09:46:01 pm
content: Quoteunless your in the uk, were the bayonet cap is more commonly found

author: TimFox
author_rank: Super Contributor
timestamp: August 05, 2021, 09:57:16 pm
content: Of course. As Edmund Burke did not say, conservatively, "If it is not necessary to change, then it is necessary not to change." Pedants can look for the actual quotation by Lucius Cary, 2nd Viscount Falkland in a speech in the House of Commons on Nov. 22, 1641.Source:https://quotepark.com/quotes/1852601-edmund-burke-if-it-is-not-necessary-to-change-it-is-necessary/

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 05, 2021, 10:17:24 pm
content: Quote from: TimFox on August 05, 2021, 02:29:32 amIndeed. I haven't read the whole thread so sorry if it has been brought up already: I was thinking that a way to implement more "intelligent" bulbs while keeping the same sockets and same electric installation would be to use PLC. Thus you could transfer both power and data using an unmodified installation.

author: TimFox
author_rank: Super Contributor
timestamp: August 05, 2021, 10:30:23 pm
content: That's an intermediate case among the following choices.1. Screwing a new light-bulby object into an existing socket powered with 120 VAC from a "conventional" wall switch or dimmer.2. Having the new smart bulb contain WiFi control, or wireless LAN through the line, from an external controller, taking power from the existing socket.3. Changing the wall switch and possibly the socket to use a more complicated interface, possibly with different power feed, to the new bulb.Personally, I think the better business plan to sell new bulbs to consumers does not require changing the socket and wiring, so (1) or (2) are reasonable.

author: Marco
author_rank: Super Contributor
timestamp: August 07, 2021, 09:44:09 am
content: It seems to me the main problem of making LED lamps compatible with dimmers is cheaping out on the electronics. A simplistic capacitive or resistive dropper obviously will not work well with Triacs, but there's no reason an active two stage DC-DC can't always and immediately pull enough current to keep the Triacs on and use the phase angle for dimming.It's more a question of marketing LED bulbs for compatibility with all dimmers and convincing consumers they should pay a premium. All the complexity of PFC, but still a lousy PF.

author: jonpaul
author_rank: Super Contributor
timestamp: August 07, 2021, 11:03:55 am
content: Marco the issue of LED compatible to existing dimmers is very well researched and solved.Capacitive or resistive droppers are not used, and most ballasts are either triac compatible or not ("dimmable")There are 100s (or 1000s) of patents and papers in the area.Design Tradeoffs are in efficiency, PFC and compatibility.I think the OP wanted input on controls rather than ballast topology.Jon

author: Marco
author_rank: Super Contributor
timestamp: August 07, 2021, 12:02:57 pm
content: It's well researched, but it's not well marketed.Triac dimmer compatible non flickering LED light, tell me where? You're not going to get there without a two stage (or two path) DC-DC converter and who has the margins or the desire to put that in a bulb? Preferably build with film capacitors instead of electrolytic.Everything is lowest common denominator trash. Maybe Apple should start making LED bulbs?

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 07, 2021, 02:26:18 pm
content: I remember a long time ago a cover plate for a light switch that adds a fade off effect to the light. The most striking feature is that it does not require messing with the wires, instead it had two spring contacts that pressed up against the screws on the side of the switch. Perhaps something similar could be done with a simple diode?Quote from: Marco on August 07, 2021, 09:44:09 amResistive dropper works just fine with dimmers, but the efficiency is poor.Quote from: Marco on August 07, 2021, 12:02:57 pmMost likely they'll also make smart switches to go with them, complete with the typical Apple markup.

author: themadhippy
author_rank: Super Contributor
timestamp: August 07, 2021, 03:24:24 pm
content: what we need is a suitable rated variable capacitor and get rid of all the fancy electronics in the led lamps,just resitive current limiting job done.

author: james_s
author_rank: Super Contributor
timestamp: August 07, 2021, 09:53:56 pm
content: A capacitor is a pretty terrible way to control the current to LEDs, not the least of the problems being the terrible flicker that it results in. There are loads of different LED driver ICs on the market today, it is a solved problem. If you're willing to spend a few bucks you can already get good quality bulbs that work well.

author: james_s
author_rank: Super Contributor
timestamp: August 07, 2021, 09:57:49 pm
content: Quote from: themadhippy on August 05, 2021, 09:46:01 pmI guess I could have said "screw-in or bayonet" but frankly I think that's being extremely pedantic. There is absolutely no difference between a ES lamp and a BC lamp other than the base/cap that is installed. My point still stands, a retrofit lamp that fits into existing light fixtures is a superior solution for most people.

author: Marco
author_rank: Super Contributor
timestamp: August 07, 2021, 10:20:54 pm
content: Quote from: NiHaoMike on August 07, 2021, 02:26:18 pmA resistive dropper only takes the top off the rectified voltage, until the mains meets the capacitor voltage there's no current to latch the triac.

author: Alti
author_rank: Frequent Contributor
timestamp: August 07, 2021, 10:39:52 pm
content: Well maybe for general lighting everyone at home should have a high efficiency current source installed in an electrical cabinet, next to circuit breakers. A "light switch" would simply short the LED allowing the current to bypass to other circuits. If the current source is set to deliver 1A then a 10W LED luminary contains 10V worth of LEDs and that is about it, no rectifiers, no smooth capacitors, no converters. Luminary could include an idling diac just in case sth goes out of control so that other lights in a loop work uninterrupted.

author: TimFox
author_rank: Super Contributor
timestamp: August 07, 2021, 11:13:38 pm
content: Some people here want me to replace what works well with an expensive re-wiring of my house, with no apparent advantage to me.

author: james_s
author_rank: Super Contributor
timestamp: August 08, 2021, 06:15:35 am
content: Quote from: Alti on August 07, 2021, 10:39:52 pmWhat on earth would be the advantage of that?? So you'd need entirely new wiring just for the lighting, all lighting would have to operate at the same current, you wouldn't be able to use a dimmer switch unless it was a PWM shunt. A failure anywhere in the loop would result in all of the lights in the house going out. You would need potentially hundreds or even thousands of volts OCV depending on the size of the house and you'd need all new fixtures and lamps. All to avoid a few dollars worth of electronics at the point of use? Seems like a very esoteric and complicated solution looking for a problem. Constant current series lighting is widely used to illuminate airport runways but it makes sense there, you have a large number of lights spread over a wide area and you want constant brightness and central control. It was at one time widely used for streetlighting for the same reason but within a house? That makes no sense at all.

author: Monkeh
author_rank: Super Contributor
timestamp: August 08, 2021, 06:57:52 am
content: That makes some sense per-room, but per-house is just ludicrous. And as soon as you have a failure, the entire house goes dark, so what, you want to install emergency lighting in every home? Goodbye all savings..

author: Alti
author_rank: Frequent Contributor
timestamp: August 08, 2021, 12:44:39 pm
content: Quote from: Monkeh on August 08, 2021, 06:57:52 amQuote from: Alti on August 07, 2021, 10:39:52 pmQuote from: james_s on August 08, 2021, 06:15:35 amI can see various advantages, including lowering investment cost, energy bills and also maintenance.The wiring of luminaries stays the same for series and parallel connection, just the arrangement changes but cables, voltages, cross sections, circuit breakers and switches stay about the same. If something was designed for 230VAC, it won't work at 1kV reliably. Also, if you design a 1A DC luminary, it is not going to work reliably when fed at 5A - that is quite understandable, you'll get a fire.As for energy - creating a 5W current source inside of a tiny bulb crammed into luminary has serious limitations as then heat comes from LEDs and the source in a small envelope and that raises the investment (mainly BOM) and affects reliability. When a physically big and efficient source can be installed in a DIN rail inside of an electrical cabinet, such constraints disappear. As for dimming - of course there is no problem in installing three variable current sources per one toilet - that is not particularly complicated but won't work with incandescent bulb triac dimmers (obviously). The question is do you need so many dimmers, maybe one dimmer per room is enough? Also, the luminary itself can include a series / parallel local switch or some DC/DC for more demanding customers.So, I cannot see any technological limitations to make future residential lighting to be powered from current sources. What is more, I believe that once people stop converting kerosene lamps to incandescent (or was it: converting incandescent to LED actually) then in 10 or maybe 20 years, after dinosaurs get extinct, a current source is what is going to be a standard for general lighting.

author: Marco
author_rank: Super Contributor
timestamp: August 08, 2021, 01:09:14 pm
content: Quote from: Alti on August 08, 2021, 12:44:39 pmNot for low voltage DC, a MHz buck with a film/ceramic capacitor can be made tiny and virtually indestructible. It's only high ratios and AC which make things hard.

author: james_s
author_rank: Super Contributor
timestamp: August 09, 2021, 03:50:18 am
content: As I mentioned before, the integrated LED retrofit bulb is a solved problem, they are available in high efficiency with long life, light distribution similar to the incandescent lamps they are meant to replace and good color rendering. The good ones cost more and they can be difficult to find, but the only reason for that is not anything technical, simply the fact that consumers tend to buy cheap. Offer them a bulb that lasts 50,000 hours and costs $20 next to a bulb that lasts 6,000 hours and costs $3 and 9 times out of 10 they'll buy the $3 bulb and then complain that it's cheaply made and doesn't last.

author: Monkeh
author_rank: Super Contributor
timestamp: August 09, 2021, 03:55:11 am
content: Quote from: Alti on August 08, 2021, 12:44:39 pmWhat happens when your whole house current source fails? I'll give you a hint: It all goes dark! Is the term 'single point of failure' new to you?

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 09, 2021, 04:17:07 am
content: Quote from: james_s on August 09, 2021, 03:50:18 amA couple of things here.First, both bulbs have lifetime claims. I have yet to to see a match between claims and reality. Some have missed long, a far greater percentage have missed short. After the CFL fiasco lifetime claims have had little credibility, and the LED products haven't turned the perception around. Often short lifetimes are blamed on bulb orientation or on fixture ventilation. Probably a lot of truth in those observations, but those factors aren't mentioned in the lifetime estimates on the bulb packaging. Making a buying decision based on a made up number is just an exercise in pencil whipping.Second, the majority of my bulbs get a few hours a day use. A 50,000 hour lifetime exceeds my expected lifetime. And exceeds the average time an American remains in the same house, even at a much higher daily usage. I don't think my heirs are salivating over the possibility of some remaining life in my bulbs, nor do I think that home buyers check for quality of bulbs when making housing offers.So maybe those buying decisions aren't idiotic. The complaints about short life are only idiotic if the bulb met its claimed lifetime.

author: james_s
author_rank: Super Contributor
timestamp: August 09, 2021, 05:46:02 am
content: I've had a few that didn't meet the stated lifetime claims but most of those were being abused in enclosed fixtures despite not being rated for it. I've replaced more LED bulbs due to obsolescence with much more efficient lamps than I have due to failure. Most of mine are also only used for a few hours a day but some are much more. I installed a Philips 8W bulb, one of those weird tri-lobe remote phosphor things in my front porch light in 2011 and it has been running dusk till dawn ever since, that's over 40k hours now and it still looks as good as the day I installed it. I recently had what was at the time a relatively low cost Ecosmart lamp fail after almost exactly 10 years also in dusk till dawn service, it's sister lamp installed around the same time on the back of my house is still going. Those early lamps were expensive, I was paying $25-$40 each at the time but they have lasted well. I had CFLs last a long time in those applications too, most were rated 6000-8000 hours and I got at least that out of the stuff that ran all night. Cycling is hard on fluorescents, especially the instant start type, it blasts a bit off the cathodes every time they start cold. In theory LED shouldn't be affected by frequent cycles but I suppose thermal cycles may stress the die or the driver PCB.Whatever the case, really cheap lamps that are cost reduced to the max run hot and are less likely to last.

author: Marco
author_rank: Super Contributor
timestamp: August 09, 2021, 06:30:51 pm
content: Quote from: james_s on August 09, 2021, 03:50:18 amShow me one flicker free (ie. no significant 100/120 Hz flicker, no dropping to zero for intensity near zero crossing and during dimmer edge cut) triac dimmable LED bulb.ICs for two stage dimmable converters exist, Dialog flickerless, but which bulbs are using them?

author: james_s
author_rank: Super Contributor
timestamp: August 09, 2021, 07:03:55 pm
content: Quote from: Marco on August 09, 2021, 06:30:51 pmThe Philips bulbs I have above my dining table are triac dimmable and have no visible flicker, I'm very sensitive to flicker so this is something I notice. These bulbs are quite old at this point so not the greatest in terms of efficiency I also have some newer Cree bulbs that I recall dim very nicely and don't appear to flicker however I don't currently have any of those on a dimmer. I don't know of a way to tell what bulbs dim nicely without flicker, maybe we need a flicker metric to print on bulb labels along with the color temperature, CRI and other data. I usually buy a sample bulb to evaluate before I buy more of them.

author: jonpaul
author_rank: Super Contributor
timestamp: August 09, 2021, 07:16:11 pm
content: Both Phillips and Sylvania Belgium makes MR-16 dimmable flicker free in 12V and 240VJon

author: Marco
author_rank: Super Contributor
timestamp: August 09, 2021, 08:50:13 pm
content: The compatible dimmer table shows a lot of red, as expected for MR-16.Triac dimmable and flicker free is really the worst case scenario for LEDs ... it's really tempting to just give up and just use a constant on time flyback or buck boost and just let it flicker at 100/120 Hz. Which is what most bulbs probably do.

author: james_s
author_rank: Super Contributor
timestamp: August 09, 2021, 10:48:37 pm
content: I have a few trailing edge dimmers and they work much better on LED bulbs than the typical triac dimmers. They're slightly more complex but not greatly, and they work equally well on inscandescent.

author: WeiZhao
author_rank: Contributor
timestamp: August 11, 2021, 12:57:19 am
content: After several round of brain storming, considering the IC/semi-conductor serious shortage.Though we have platform solution for senor, still next development direction would not consider the sensor or intelligent too muchThanks for providing so many good suggestions. Let me feel the power of EE from global.