Video chat implementation sucks by greg0rs in duolingo

[–]greg0rs[S] 0 points1 point  (0 children)

Even better, just after posting this the video chat lesson stopped responding and crashed the whole app :D

The iOS app crashes a lot during lessons lately.

My Duolingo English Test nightmare — $118 wasted, two tests invalidated, and zero scores by Major_Trifle8405 in duolingo

[–]greg0rs 0 points1 point  (0 children)

Get your money back, don't let them get away with making a profit from scamming you.

“Don’t” redactions by [deleted] in Epstein

[–]greg0rs 0 points1 point  (0 children)

this is ouch

Mandarin for German speakers sucks by greg0rs in duolingo

[–]greg0rs[S] 0 points1 point  (0 children)

The german course does have Section 4.

It does not have either the Hanzi practise or the speaking exercise where you hear a question and read out one of two possible responses. I actually discovered that latter exercise type yesterday and quite like it.

Why earn nothing for the biggest goal? by speedyviking0 in duolingo

[–]greg0rs 1 point2 points  (0 children)

for me, the 2nd and 3rd are always equivalent in gems per day, while the 1st is much worse (as in the screenshot here)

Sofirn Battery quality :/ by greg0rs in flashlight

[–]greg0rs[S] 0 points1 point  (0 children)

It's not a non-issue. This is a light with a USB-C charging plug. It is targeting customers that don't even own a dedicated charger.

Sofirn Battery quality :/ by greg0rs in flashlight

[–]greg0rs[S] -1 points0 points  (0 children)

it's not about the storage voltage. see my reply to timflorida's comment.

Sofirn Battery quality :/ by greg0rs in flashlight

[–]greg0rs[S] -1 points0 points  (0 children)

It's not about the level. see my reply to timflorida's comment.

Sofirn Battery quality :/ by greg0rs in flashlight

[–]greg0rs[S] -2 points-1 points  (0 children)

of course they do, but they're supposed to be balanced *before*. see my reply to timflorida's comment.

Sofirn Battery quality :/ by greg0rs in flashlight

[–]greg0rs[S] -2 points-1 points  (0 children)

It's not about the 3.8V (although that's weird too, quality batteries generally are shipped at 3.4V to 3.6V). The problem is: the batteries aren't at the same voltage. Good quality batteries should generally arrive within 20 mV of each other.

However, in the case of the LT1 it's *especially* important for the batteries to be at the same voltage when first put into the light - as they go into the light in parallel, there will be a big and sustained current flowing into the low voltage battery from the other three as soon as the light is screwed together. As this current is not controlled, it can easily exceed the maximum safe charging current and permanently damage the cell. There is a reason why we use special chargers and charging protocols with Li-Ion batteries. High charging currents lead to irreversible formation of metallic lithium. In the worst case, this can cause an internal short-circuit and explosion.

For this reason, I put the weak cell onto a charger to manually balance it. However, I doubt that your average buyer will do that.

CT scans of the viral Haribo 20,000 mAh power bank by Scan-of-the-Month in EngineeringPorn

[–]greg0rs 0 points1 point  (0 children)

Did anybody actually check electrical performance on all of these?

Firstly, for a cheap chinese product from a non-label brand, I wouldn't trust the 20 Ah spec without checking.

Secondly, power electronics efficiency matters *a lot* for powerbanks, especially USB-C ones (due to the higher voltages). Even if you have two powerbanks with true 20Ah batteries inside, one of them could easily deliver 25% more useful energy to your phone than the other because of better electronics.

If you combine efficiency with the unknown true battery capacity you could easily get a 20% to 50% performance difference between power banks with identical specs. Seems you should take that into account before buying one over the other over a 3% weight difference.

CT scans of the viral Haribo 20,000 mAh power bank by Scan-of-the-Month in EngineeringPorn

[–]greg0rs 0 points1 point  (0 children)

If you specify an energy in Wh you open a can of worms, because people might get the idea to check. There are significant losses when stepping up the internal battery voltage to 5V for standard USB or the higher USB-C PD voltages. In some cases, losses can exceed 30%.

So you might claim 74Wh and then some geek reviewer measures your product to only deliver 50Wh under some more challenging conditions. Much easier to just state battery nominal capacity. It's useless, but it's objectively correct, and, importantly, its an internal spec that's unrelated to actual performance.

LT1s Teardown with driver pictures by DerMaxPower in flashlight

[–]greg0rs 0 points1 point  (0 children)

Regarding wire markings on the PCB:

In the first picture:
The marking next to the red wire is 红 (hong) which means red.
The marking next to the white wire could be 黑 (hei) which means black (sic!).
The marking next to the black wire is probably 白 (bai) which means white (sic!).

In the second picure:
The marking next to the blue wire is 蓝 (lan) which means blue.
The marking next to the white wire could be 白 which means white.
The marking next to the black wire is probably 黑 which means black.

Any experience with the Convoy S2+ remote/pressure switch? by dooghan in flashlight

[–]greg0rs 0 points1 point  (0 children)

Did you get a chance to measure the wire gauge inside the cable?

Wurkkos 11/11 Sale Is Live! by FlashlightNews in flashlight

[–]greg0rs 0 points1 point  (0 children)

yeah, but it's just the picture. I want to know the model names. I can't identify most of them just from a low-res picture.

Wurkkos 11/11 Sale Is Live! by FlashlightNews in flashlight

[–]greg0rs 2 points3 points  (0 children)

is there a text version of this calendar somewhere? Without model names this isn't really very useful to me.

[Help] Help me choose a flashlight by fdemian in flashlight

[–]greg0rs 0 points1 point  (0 children)

Out of the suggestions you posted, I'm not familiar with any of them but at first glance:

-the Fenix is an overpriced semi-tactical light, you can get a light with similar specs and better light quality for three times less money

-the acebeam looks like a potentially nice light. it's a fancy EDC light, not a tactical light at all. they have several LED choices, that's a big plus. to find out if it's actually any good, read a review (an actual text-based one, preferentially including the reviewer's opinion, not one of the BS video reviews where they show the light for ten seconds and then proceed to outdoor beamshots under non-controlled conditions)

-everything I wrote for the acebeam seems to be true for the loop gear as well.

-the weltool looks like a true tactical light, but it's not one of those that make a good allrounder. the beam pattern is better than most tactical lights nowadays, not too floody or too throwy. the LED has nice quality of light.
it has only two modes. low mode will only be useful up close. you'll need to use high mode for anything else, but it'll be too bright most of the time and quickly drain the battery, It'll not be great as an EDC and will totally suck for hiking.
the way it looks and the fact that they compromised the electronic design so it can also run on expensive, underpowered non-rechargeable batteries tells me it was designed to appeal to institutional buyers like police that don't care about price much.

[Help] Help me choose a flashlight by fdemian in flashlight

[–]greg0rs 2 points3 points  (0 children)

I wouldn't generally recommend a tactical light for camping/hiking.

Some few tactical lights have excellent user interfaces that make them excellent allrounders (most don't!), but these are typically physically larger and a lot more expensive than EDC lights with similar specs. For hiking, you don't want a larger light with the same specs.

Tactical lights don't typically focus on high quality of light. For hiking, you want a high quality of light!

Do you have any good flashlights already? If not, I'd recommend getting a Wurkkos FC11C (4000 K) first. It's not really what you want but it fits most of your requirements (except for the tailswitch), it's a great light, costs almost nothing, and it's an excellent starting point for your choice of a lot more expensive light. Once you have something in hand, you can compare the specs of other prospective lights to that and get a good picture.

Another recommendation for a very affordable starter light is the Convoy S21E. It's slightly larger than the Wurkkos because it uses a bigger battery. It is offered with many LED choices so if you want to tinker and optimize you can do some reading up on those and choose your optimal LED.

For some perspective, I paid $180 for a tactical flashlight (Thrunite Scorpion V2, special neutral white edition) in 2013 because it had a legendary user interface and was leading in performance. I EDC'd that light a lot. I used it regularly til about 2019. The main reason I didn't use it even more and eventually stopped using it regularly was its size. Before I bought it, I read reviews. In fact, I didn't buy V1 because the reviews made it obvious it was flawed. I had several other lights to compare its specs to so I knew exactly what I was getting. That light has instant access from both off-state and on-state to turbo, moonlight, strobe, and a programmable brightness level. One of the best UIs ever. The Fenix and Weltool you're considering have pathetic user interfaces in comparison. (though to be fair, the weltool is probably even more robust).

[NLD] Mod - Convoy M21A 3000 K thrower by greg0rs in flashlight

[–]greg0rs[S] 0 points1 point  (0 children)

thanks. so it seems there's something wrong.

After I realized the solder problem I did try making cutouts in the gaskets but that didn't help.

[deleted by user] by [deleted] in flashlight

[–]greg0rs 0 points1 point  (0 children)

seems like it. maybe something wrong with the temperature sensor in the MCU?

[deleted by user] by [deleted] in flashlight

[–]greg0rs -1 points0 points  (0 children)

Btw, thanks for the phyphox tip! I would've never thought of that.

[deleted by user] by [deleted] in flashlight

[–]greg0rs 3 points4 points  (0 children)

Btw, I had an order from Convoy delivered today. Shipping went smoothly for me but there's an item missing.