Is PWM shimmering bad for epilepsy

Hi all, I was just about to purchase a Nitecore EC11 but read a review stating..

I also detected low frequency Pulse Width Modulation (PWM) when using the EC11 on low, medium and high modes. As with PWM, this is only noticeable when illuminating quickly moving objects. Types of instances include your hand in front of the light…the blades of a fan…flowing water…that kind of thing.

i suffer from epilepsy and photo sensitive, I've noticed little reactions to my epilepsy from my TM26 and AceBeam EC50 Gen II and worried this might cause me to have a seizure.

could any one who owns a EC11 tell me if they notice this PWM.?

Wanted a pocket flaslight with high lumen and this looked perfect for me! Liked the red led

Toma said:

Hi all, I was just about to purchase a Nitecore EC11 but read a review stating..

I also detected low frequency Pulse Width Modulation (PWM) when using the EC11 on low, medium and high modes.
...

i suffer from epilepsy and photo sensitive, I've noticed little reactions to my epilepsy from my TM26 and AceBeam EC50 Gen II and worried this might cause me to have a seizure.

could any one who owns a EC11 tell me if they notice this PWM.?

Click to expand...

if you already know the light has PWM, and you already know you have photo sensitive epilepsy, why would you buy the light?

asking people here, who do not have epilepsy, whether they "notice" PWM does not change the facts

a lot of people dont "notice" or care about PWM
I otoh, will not buy a light I know has PWM, and I dont even have epilepsy

Sounds like a great question for a flashaholic Neurologist! Wouldn't think it would be a slow enough rate to bringing on a seizure. I'd be interested in finding out through too.

Anyone know of any Neurologists on this forum?

I may be wrong but I thought photosensitive epilepsy was set off by a certain frequency range and that even the lowest frequency PWM would be too fast to set it off.

I believe that is correct. The trouble starts when the frequency of the flashing matches that of certain brain waves. The rule of thumb is to keep the flashing below 5 per second or above 30 per second. In general PWM will occur a frequencies far far higher than 30Hz.

For someone with epilepsy, why guess and gamble with ANY PWM?

buy a light with NoPWM so you dont have to expose your brain to the strobing, at any frequency

Generally speaking, Nitecore uses PWM, Olight and Thrunite tend not to use PWM (but depends on the specific mode and model)

Zebralight does not use Pure PWM, and they make great lights, their circuit does have strobing, but it is not full On, full Off like true PWM

more info here:
List Lights that use NO PWM

jon_slider said:

if you already know the light has PWM, and you already know you have photo sensitive epilepsy, why would you buy the light?

asking people here, who do not have epilepsy, whether they "notice" PWM does not change the facts

a lot of people dont "notice" or care about PWM
I otoh, will not buy a light I know has PWM, and I dont even have epilepsy

Click to expand...

im very new to led flash lights and jumped in to it head first and bought a few lights, I didn't know about PWM until today after finding the review for the EC11.!!!!!

jon_slider said:

For someone with epilepsy, why guess and gamble with ANY PWM?

buy a light with NoPWM so you dont have to expose your brain to the strobing, at any frequency

Generally speaking, Nitecore uses PWM, Olight and Thrunite tend not to use PWM (but depends on the specific mode and model)

Zebralight does not use Pure PWM, and they make great lights, their circuit does have strobing, but it is not full On, full Off like true PWM

more info here:
List Lights that use NO PWM

Click to expand...

thank you for the link.

Toma said:

im very new to led flash lights and jumped in to it head first and bought a few lights, I didn't know about PWM until today after finding the review for the EC11.!!!!!

Click to expand...

that is normal, you are doing fine
learn as you go

most people dont care about PWM, and will say things like, "I dont notice it, so it does not matter", or "its at a high frequency, so it does not matter"

then there are lights with circuit noise, for example the Eagletac, even though some reviewers claim they "just have circuit noise, not PWM", the lights are not true Constant Current.

since you are looking at a CR123 light, know that the high brightness specs are only for LiIon… so you need to learn about battery choices, and decide if you want to use disposables or rechargeables.. and you should know that LiIon requires special chargers and safe handling protocols.

welcome to the forum, enjoy your lights!

some of the criteria to learn more about
PWM, yes or no
battery options and types
Color Temperature
CRI

example, Olight tends to use High Color temperature (cool white), and low CRI (makes red look brown)

here is a CR123 Olight that is offered in Neutral White (though still low CRI, and afaik NoPWM, with the possible exception of the moon mode, I have not confirmed either way)

Didn't know the flashlight could be so in Depth!...there is much to be learned. Will have a look at the non PWM lights and make a choice. Thanks again :0)

No expert but something about 3 flashes per second is stuck in my head about this.

DISCLAIMER: I'm not a medically qualified person, so take my words with a bit of scepticism.

Did you have problems with oldtime pre-flatscreen TV screen? Those flash at 50/60Hz.
If they didn't trigger you, most PWM probably won't either.
However, I'm not certain whether it's worth the risk.

I though I had seen that wave pattern on TVs that were videoed before. When I was younger I did get headaches after watching TV for a very long time. Don't now. Never thought about it but that may have been why.

TheBelgian said:

DISCLAIMER: I'm not a medically qualified person, so take my words with a bit of scepticism.

Did you have problems with oldtime pre-flatscreen TV screen? Those flash at 50/60Hz.
If they didn't trigger you, most PWM probably won't either.
However, I'm not certain whether it's worth the risk.

Click to expand...

no, no problem at all with the tv screen.
My first purchase was a Nitecore TM26 and remember when I first went out with it I felt a little funny from it but didn't understand why, obviously I never put strobe on as I'd be break dancing on the floor :8)
it was only when I came across the PWM review I clicked and got worried.