2012 RRT01 - Why is it pulsing?

LED Flashlights – General Info CR123A Flashlights
1

One of my rotaries is pulsing at a very low frequency (maybe 20 to 30 Hz). The opple doesn’t take a sufficiently long sample, but you can catch it with some luck:

Hope you see the step-up from 50 to 60 lx (mean value, distance light-sensor a few mm). Looks like a rectangular modulation since the mean value really jumps.

It is visible only in the lower sub-lumen range. Neither my EYE10 (original) nor my 2019 RRT01 (XP-L Hi 5D) show this pulsing. I tried two drivers in this 2012 RRT01 (XP-L2, 3000K, CRI about 80). I tried different batteries.

It is absolutely no problem except it drives me crazy knowing that it’s there.

Edit: One difference - the original driver screw had no grip, so I replaced it with a slightly longer one.

2

So it is the low frequency step that is your concern (almost like a DC level shift)?

What about the higher 1kHz pulsing (likely PWM), is that seen or a concern?

3

Hi kennybody. I don’t think it’s PWM. The pulse width doesn’t change, the modulation depth just decreases with current. The ripple has a wavelength of 1 ms, which gives 1 kHz. Should be visible if the modulation depth were higher, but isn’t.

I got a PM and learned it’s a common problem. Strangely, it feels better knowing others suffer from this, too :partying_face: .

4

I can see the flicker on one of my Jetbeam Rotaries, when I stare at the LED reflected in the reflector, when set to 0.1 lumens, here is the Opple data
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I can also see the flicker at 0.01 lumens, (no Opple data)

I cannot see the flicket at 1 lument, here is the Opple data

I have occasionally seen the flicker, on the ceiling, when tailstanding at around 5 lumens… I have been able to make it stop by turning the light up to a higher level, and then turning it back down… I believe this is challenging the battery to stabilize its output, not sure.

In the past I suspected the issue was caused by a stuttering Protection Circuit in a battery, but Im using an Unprotected battery now.

I still dont know why this is the only one of my rotaries that flickers like this. Ive tried multiple LEDs, both 219b and 519a, and Ive tried multiple drivers. Ive cleaned all the contacts on the pill and battery, I even polished the end of the battery tube, hoping to eliminate any oxides that could be causing poor contact.

Nothing Ive tried has eliminated the flicker. I gave up trying, I still carry the light, it has my personal favorite LED atm, a dedomed 519a 4500k.

It is this light, Jetbeam TCR-1, my grail host:
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I have had to let go of my expectations of perfect flat regulated outputs… the bottom line seems to be that all lights have some sort of electronic oscillation, even if it is not PWM, there can be flicker. In that regard, I really like how the Opple gives a Risk Assessment. I think frequencies above 3000hz might not be as biologically disruptive… as frequencies below 1000hz, not sure.

I dont use the light as long term ambient light, so my exposure to the flicker is not for long periods. I have not had any issues with headache or eye strain. I do however have a strong dislike for visible flicker on the target. I usually dont experience visible flicker, except as described on my ceiling. The flicker I see is when staring directly at the LED, at sublumen levels, which is not something I make a habit of doing… lol

for comparison, here is my other TCR-1 w sw45k.
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On this one I cannot see the flicker. I set it to 0.1 lumens and got this Opple data:
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Nothing in the Opple Data seems to show any difference to the light that I can see flicker. Iow, my eyes see stuff Opple does not capture.

5

My 2021 RRT01 is also flickering/pulsating on the lowest levels. I’m not sure anymore, but I think the flickering wasn’t there in the first few days after I got it.

6

flickering/pulsing from lower level to high level on 2021 too.
It's just hard to see on higher levels.

7

What chip is used for the driver—is there any identification available?

That 1kHz is quite repeatable and seen in all the different examples so it must be a feature or “programmed” into the controller. Something like a fixed frequency oscillator. Might it have a boost/buck converter?

8

However it is done, the output is unregulated. CR123 batteries work.