Comparing Flicker on Anduril and non Anduril versions of Sofirn SC21 lights. Both lights have LED swaps to 219b 3000K.
I measured 3 output levels, I dont know what it all means yet, but it seems the SC21 Pro flickers more than the SC21 Mini:
note the difference in Flicker Index:
The SC21 Mini is claimed to be regulated, and more efficient, based on these runtime charts from zeroair.
Is that just constant current vs PWM?
I dont know if either of those lights uses constant current… Im honestly not educated on what terms apply.
Regulated vs Unregulated?
I really dont understand why the Anduril light, SC21 Pro, flickers more…
Also dont understand why the nonAnduril light, SC21 Mini, has really low flicker at 1 lumen and 50 lumens, but flickers a lot at 6 lumens…
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new comparison, Sunwayman V11r and HDS, both w sw45k
output seems more stable on the V11r:
Flicker Index is higher on the HDS:
jon,
Have you got access to an oscilloscope and a photo-diode?
It would be interesting to see what’s actually going on.
I do have some lights that have PWM at medium settings but run CC at full.
All I see there is artifacts from the driver. Usually 15K Hz+ or something like that.
The V never drops to zero while doing this.
Plus they do tricks at moonlight to get enough V to wake up the LED. Often a slower PWM.
All the Best,
Jeff
Jeff,
thanks for helping explore the subject of flicker. I dont own a scope, but I think the Opple is giving useful flicker measurements, as a basis for comparison.
PWM technically requires turning the LED completele off and on. A drop in output to Zero, which would be termed 100% Modulation Depth.
This example of Opple data, shows Percent Modulation is greater on the HDS, as is the Flicker Index, and the Frequency of Oscillation:
I dont know what it all means, just noticing differences in the Opple measurements at this stage 
Neither light in this example flickers visibly.
Im still learning visible threshold benchmarks…
I think 100% modulation can be visible, but only if it is at a Frequency below 1000Hz. I think a Flicker Index below 0.5 is not considered visually noticeable.
It can be tricky trying to pin down what’s annoying PWM wise.
I have come to the opinion that’s it’s the off time portion of the duty cycle that annoys.
I’ve got a lamp that has a 100Hz PWM Fq. Slowest PWM I’ve ever seen.
Full off V at the off portion.
At 5%-10% Duty Cycle - it’s like barf city to use - with a moving subject I can hardly stand it.
At 50% it’s still awful.
But at a 90% duty cycle, it’s just fine. The on voltage is the same. The only difference is the amount of time the light off during the cycle.
With another light that has a PWM of 3600Hz and a Duty Cycle of 4%(?) - I on can see it with the waving finger test. But it is not annoying - at least in short time use.
Others have said that lights that annoy the heck out of some, don’t bother them at all.
Interesting trying to put some data to objective observations.
All the Best,
Jeff
exactly!
The flicker features of the Opple 3 are interesting to explore.
The results are sometimes suprising and unexpected, for me… in any case entertaining
Jeff,
I have a digital oscilloscope and measuring flicker would give me something else to use it for. How would I connect the photodiode?
Here is what I ended up with.
It also references some others. Including Terry Os great test of all sorts of sensors if you really want to geek out. His is the design I used.
The photo diode is cheap. Got it on Amazon.
I eventually made the tube longer and did away with the filter. Too much trouble.
I just held the light off axis to keep the diode from clipping.
All the Best,
Jeff
Both have hi frequency modulation , no flicker.
modulation depth and flicker frequency of a non anduril light (blue on left), and an anduril light (red on right), tested at 1, 6, and 50 lumens:
Im suprised to see the red host has such deep fluctuations in brightness… on all 3 modes tested
also suprised that the blue host is flicker free on only 2 out of 3 modes…
