AGI I don't find the threads and posts currently. You can build a cheap BPW34 setup which you find in the oscilloscope thread. It's accurate enough for several hundreds of Hertz but needs further tweaking for high frequencies in the range of xx,xxx+ Hz (tens of thousands), which nobody so far could contribute to. I measure flicker% as (max-min)/max. The eye pain I get from LED bulbs can be instantly noticeable and is for sure always aggregating over time. No strong pattern found so far that relates to flicker (speed, type) or spectrum.

AGI Are you bothered by fluorescent lamps as well?

Yes, and the symptoms depend greatly on the type of lamp, but again no pattern other than the same lamps always cause the same symptoms.

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        KM I would think that figuring out what is wrong with a lamp be way easier than with a laptop or computer display, given the system is rather simple and no software is involved. Instead...

        I was looking at a comparison between LED and incandescent bulbs. Okay, the publisher is a company manufacturing LEDs, but the only mention to flicker is with regard to "Cycling (Turning On/Off)".

        "LED... produce steady light without flicker...

        Incandescent lights (similar to LED) do not generally flicker and/or cycle on and off as the bulb reaches the end of its useful life....Incandescent lights also turn on rather instantaneously and produce steady light generally without flicker."

        Later on in the "Dimming" topic of the summary table, they write "LEDs are very easy to dim and options are available to use anywhere from 100% of the light to 0.5%. LED dimming functions by either lowering the forward current or modulating the pulse duration."

        So maybe what we call flicker, here is called "pulse modulation". Still, there is no note at all about any potential symptom triggered by such pulsing. Is lowering the forward current the mechanism used in LED displays without PWM? Perhaps the LED that do not bother me work under constant current, not sure if this info is stated on the bulb specs. Also, most LEDs in public spaces like work office are non-dimmable. Do they still work under PWM?

        I do not rule out color rendering index either. I wonder whether there are wavelengths that my eyes/brain cannot well digest.
        Does anyone feel any difficulty concentrating / minor eyestrain when using incandescent bulbs, depending on the temperature of the filament / colder versus warmer light?

            AGI incandescent bulbs are the best for the eye and do not flicker. I try to use them or halogen. Energy saving bulbs are bad for the eye: no red spectre and flickering.

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                Alexmam I would think there is no lack of red.
                In general, I agree with you. Even the fluorescent lamps I can stand I believe are not that healthy on the long term. Who knows how many mild symptoms, which may pile up over time, are assigned to else than bad lighting.
                Still, unless you google on side effects, you won't read anything worrisome about LED or fluorescent lamps. As a matter of fact, as for displays and computers only an insignificant minority is affected. If you add energy saving to no complaints, shortly there will be LEDs everywhere :-(
                Hopefully there will be some more suitable innovation for us sensitive people.

                    AGI you won't read anything bad about LED because people do not die instantly from it and because it is convenient for manufacturers. My life has changed since LEDs were introduced: eyes are very tired and I can't use any new laptops/TVs or monitors. It sucks.

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                      AGI Perhaps the LED that do not bother me work under constant current, not sure if this info is stated on the bulb specs.

                      I think all LEDs flicker more or less when connected to the electrical grid. They have to convert the 50/60 Hz AC to DC and don't do it perfectly. Perfect would be zero flicker, not even 0.03% (@100 Hz), as low as that seems it's still flicker and we can't be sure it's not the cause for our eye strain. Even "flicker-free" monitors still flicker at varying degrees. I think no matter what you buy, it will flicker, unless it is powered by simple batteries.

                      You could try some of those small, cheap battery-driven reading lights that you clip to books. They usually truly have no flicker at all because the battery delivers a direct current. If your eyes still hurt, that might be some new info.

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                          KM You could try some of those small, cheap battery-driven reading lights that you clip to books. They usually truly have no flicker at all because the battery delivers a direct current. If your eyes still hurt, that might be some new info.

                          Good point!
                          I had a small lamp powered via USB but I gave it away thinking it would be nasty. I should have tested that too.

                          Alexmam incandescent bulbs are the best for the eye and do not flicker.

                          One major problem is that it gets quite warm when the temperature in your office is already set to 26C and you turn on a couple of desk lamps with 40W incandescent bulbs :-(

                                AGI 40W lamps are not gonna heat the room. I use 60W table lamp and I don't feel any heat at my working table. Heat is the least of my worries)

                                  3 years later

                                  I haven't read the whole thread (a 'search in thread' feature would be great, @Slacor 🙂 ) but:
                                  Is there an android camera app that can reliably use fast shutter speed (in order to detect pwm)?

                                  AGI They do when they're malfunctioning though 😆

                                    2 years later
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