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What Happened to the 100000 Hour LED Bulbs?

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Re: What Happened to the 100000 Hour LED Bulbs?

#461

Post by ajuc »

handzbagz wrote: post #383
TheSpiceIsLife wrote: post #378

Earlier quoted context omitted.

LED flicker could prove harmful or fatal if you work with anything that rotates or reciprocates. The rotating / reciprocating mass may appear stationary at some RPM. Just a reminder to only ever use incandescent or halogen lights around machinery you can touch while in operation: drills, lathes, mills, slotting machines, etc.

Just how likely is this to happen though, it would have to be the only light source and be flickering with exactly the same frequency as the machinery is traveling at (which i assume for most devices varies a lot). Not saying it can't happen but it does seem stupidly hard to achieve.

> which i assume for most devices varies a lot

Most will flicker at a multiply of the power line frequency (60 or 50 Hz depending where you live).

It's so common, that most digital cameras have a setting to set the power line frequency, so they can reduce the flickering in the footage.

Incidentally - many alternating current engines are also working with multiples of the powerline frequency, because it's easier that way.

Re: What Happened to the 100000 Hour LED Bulbs?

#462

Post by Tsubasachan »

Moru wrote: post #375
mrb wrote: post #235

Lifetime isn't even my #1 concern with LED bulbs. It's strobing/flickering. I film all the LED bulbs I buy in slow motion at 240 fps with an Android phone, and play the movie back on a PC with mplayer using the dot(".") key to move frame by frame. Here is a shot I made comparing 2 brands of LED bulbs: https://youtu.be/QbenId_F2RQ (Edit: yeah you don't have to transfer to a PC, just playing back in slow motion on the…

I usually just move my phone really close to the lightbulb and watch the live camera view. At a certain distance/angle you can usually see the flicker as banding across the screen. I saw a test in a Swedish newspaper lately that showed IKEA's cheapest lightbulbs as one of the less flickery ones in the test. IKEA art.nr 303.887.64. So much for the price to guide you.

Bought an IKEA led lightbulb for €3 and the packaging says it should last 15000 hours. Not bad really.

LED lights are alright. Lots of people think that everything used to be better but my memory is too good to fall for that trap.

Re: What Happened to the 100000 Hour LED Bulbs?

#463

Post by 0x70dd »

mrb wrote: post #235

Lifetime isn't even my #1 concern with LED bulbs. It's strobing/flickering. I film all the LED bulbs I buy in slow motion at 240 fps with an Android phone, and play the movie back on a PC with mplayer using the dot(".") key to move frame by frame. Here is a shot I made comparing 2 brands of LED bulbs: https://youtu.be/QbenId_F2RQ (Edit: yeah you don't have to transfer to a PC, just playing back in slow motion on the…

I noticed the same thing when I was playing the guitar. The constant flickering combined with a vibrating string at a high frequency produces a nice looking effect [1], which can be observed with a naked eye (unlike the one in the video).

[1] https://www.youtube.com/watch?v=ttgLyWFINJI

Re: What Happened to the 100000 Hour LED Bulbs?

#465

Post by nitrogen »

Dylan16807 wrote: post #421
m463 wrote: post #394

Earlier quoted context omitted.

I would imagine there's a higher-than-average chance of this because most AC motors are definitely syncronized with the 60hz (or 50hz) AC source. There's a chance the lights might also derive from this.

> There's a chance the lights might also derive from this. If the light is flickering it's absolutely guaranteed that it's derived from this. But it's hard to imagine a lightbulb that emits a short enough pulse of light to make something look stopped. Even an absolute garbage one-way rectifier will be emitting light more than a quarter of the time. That can make a tool look odd, but it won't make it look still.

If the light is flickering it's absolutely guaranteed that it's derived from this.

Not necessarily. If it's a 50/60 or 100/120 Hz flicker then yes, but LED lights with a cheap switching power supply might still flicker at the switching frequency, which could be say 400Hz or something.

Re: What Happened to the 100000 Hour LED Bulbs?

#466

Post by nitrogen »

yeutterg wrote: post #430
MPSimmons wrote: post #395

Earlier quoted context omitted.

I can spot a Cadillac or GMC vehicle on the road a mile behind it from the flicker of the taillights. It's terrible.

Agreed. Most car manufacturers' LEDs flicker (just look at any slow-motion video, such as those on Top Gear or The Grand Tour), but GM's are at a much lower frequency that is visible if the vehicle is in motion, or you are in motion.

I always wondered if anyone ever tried to encode information into the flicker pattern of LED tail lights. I can think of a lot of uses, good and bad.

Re: What Happened to the 100000 Hour LED Bulbs?

#467

Post by Cthulhu_ »

mrb wrote: post #235

Lifetime isn't even my #1 concern with LED bulbs. It's strobing/flickering. I film all the LED bulbs I buy in slow motion at 240 fps with an Android phone, and play the movie back on a PC with mplayer using the dot(".") key to move frame by frame. Here is a shot I made comparing 2 brands of LED bulbs: https://youtu.be/QbenId_F2RQ (Edit: yeah you don't have to transfer to a PC, just playing back in slow motion on the…

I was in a hotel room a while ago which had some seriously flickering LED lights, just everywhere; moving around you could definitely see it. Wasn't pleasant.

Re: What Happened to the 100000 Hour LED Bulbs?

#468

Post by Dylan16807 »

nitrogen wrote: post #465
Dylan16807 wrote: post #421

Earlier quoted context omitted.

> There's a chance the lights might also derive from this. If the light is flickering it's absolutely guaranteed that it's derived from this. But it's hard to imagine a lightbulb that emits a short enough pulse of light to make something look stopped. Even an absolute garbage one-way rectifier will be emitting light more than a quarter of the time. That can make a tool look odd, but it won't make it look still.

If the light is flickering it's absolutely guaranteed that it's derived from this. Not necessarily. If it's a 50/60 or 100/120 Hz flicker then yes, but LED lights with a cheap switching power supply might still flicker at the switching frequency, which could be say 400Hz or something.

You have to be intentionally wasting money to put in a transformer big enough to handle 400Hz, and once you get into the lots of KHz where a supply like that is happy I think your "please don't explode" capacitor on the transformer is enough to prevent flicker.

Re: What Happened to the 100000 Hour LED Bulbs?

#469

Post by mcv »

NeedMoreTea wrote: post #423
handzbagz wrote: post #383

Earlier quoted context omitted.

Just how likely is this to happen though, it would have to be the only light source and be flickering with exactly the same frequency as the machinery is traveling at (which i assume for most devices varies a lot). Not saying it can't happen but it does seem stupidly hard to achieve.

Pretty common, about as common as the wagon wheel effect in 24fps film movies. In just the same way, the item can appear to stop, run slow, or run backwards, just as with film. No it does not have to be the only light source, just the nearest one to the machinery. Fluorescent tubes are most noticeable, LEDs a little less. Tungsten or Halogen are the only sensible option for workpiece illumination.

Or, of course, just use a LED that properly smooths out the DC. It's not hard to do, and a quality LED manufacturer should get this right. The only excuse for flickering is a cheap LED that cuts cost for circuitry.

Re: What Happened to the 100000 Hour LED Bulbs?

#470

Post by mcv »

icelancer wrote: post #436
dsfyu404ed wrote: post #405

Earlier quoted context omitted.

Most people spec'ing out machine shops are not experts in lighting other than more = better. This is a really, really low risk we're talking about. Like basically the stars have to align for someone to get hurt.

No, it simply isn't that rare. You haven't been around wood shops and machinery much if you think that.

Are there any statistics on this? That seems like the obvious way to settle this issue.

So far, the discussion sounds like it's a theoretical possibility. If it's a real possibility, then it's something that should have happened a number of times.

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