LiteFlux LF5XT - the ultimate AA light? (Part 2)

[orcinus]

Ha! I think i've nailed it!

The bugs are, in fact, related!
It seems that, while the emitter is exposed to light, a cap is charging somewhere. If the voltage on that capacitor exceeds a certain threshold, it first needs to discharge (first click) for the MCU to start functioning properly and lets you switch the light on (second click). Above an even higher threshold, discharging doesn't help and it's completely locked out until you bring it in the shade and click it once.

The thing is, i've just realized the 15 second lock out isn't, actually, a 15 second lock out!

It seemed like it yesterday because i was in a constantly lit room! But the fact is, the amount of time needed for the lockout varies with the amount of light the emitter is exposed to. In complete darkness it never locks out, no matter how much you wait. In bright light it takes 15 seconds. In even brighter light it's shorter than that.

So it seems like it's most definitely a hardware bug.

 

[vhyper007]

Hello Again Kool,

I am about to take the plunge (am feeling lucky) but I haven't seen the output in lumens at 100%. Is it published in your literature or have I just overlooked it?

Anyone, please feel free to reply if you know the answer. Also does anyone have regrets having bought it? As I said, I'm feeling lucky.

TIA,
vhyper007

 

[HKJ]

It seemed like it yesterday because i was in a constantly lit room! But the fact is, the amount of time needed for the lockout varies with the amount of light the emitter is exposed to. In complete darkness it never locks out, no matter how much you wait. In bright light it takes 15 seconds. In even brighter light it's shorter than that.

So it seems like it's most definitely a hardware bug.

But it is not present in all LF5XT, I have been trying with the two I have and could not reproduce your problem.

 

[orcinus]

But it is not present in all LF5XT...

Yeah, i'm aware of that...
Thanks for checking, by the way!

 

[vhyper007]

PLEEZ,
somebody tell an elderly country gentleman how many lumens at 100% the LF5XT has.

Kindly,
vhyper007

 

[LED-holic]

PLEEZ,
somebody tell an elderly country gentleman how many lumens at 100% the LF5XT has.

Kindly,
vhyper007

It's hard to say for sure, but it's slightly brighter than my NiteCore D10 on max, so I'd guess around 140 lumens...

 

[GBH2]

PLEEZ,
somebody tell an elderly country gentleman how many lumens at 100% the LF5XT has.

Kindly,
vhyper007

How about some lux readings? - http://www.light-reviews.com/liteflux_lf5xt/review.html

 

[GBH2]

Yeah, i'm aware of that...
Thanks for checking, by the way!

I cannot seem to replicate the different operation in bright light or darkness. However, there are some interesting things going on - I am hesitant to call them bugs at this point.

I think that the MCU "goes to sleep" to limit drain on the batteries. (I think that this may be resulting in the 15 sec "lockout" we seem to have experienced)

I can turn the light on everytime after 15 seconds with a deliberate full press.(while a casual press (approx. 3/4) will turn it on every time prior to the approx. 15 sec.

I am wondering if the switch is a simple on/off or if it has 2 stages - 1 to wake up the MCU and then to transmit the input to the MCU.

or maybe I am crazy.

Just to be clear to anyone reading this thread - I love this light and I highly recommend it!

 

[orcinus]

I am wondering if the switch is a simple on/off or if it has 2 stages - 1 to wake up the MCU and then to transmit the input to the MCU.

I doubt it's a 2-stage switch, since that would probably require an additional signal path to the head or some kind of a sense resistor (and i can't see anything like that in the circuit board pics Khoo has posted).

It's more likely what you're experiencing is caused by the switch bounce. Switches sometimes "bounce" - a single click rebounds and gets interpreted as two quick, sequential clicks. It gets more pronounced the more force you use when pressing the button.

Just to clarify - i love my LF5XT too! And the way it's acting doesn't really bother me that much. I'm just curious about it's non-standard behaviour.

Edit: I've just kept my LF5XT in complete dark for an hour, and guess what! It switched on at the first click! Which confirms my theory.

 

[matrixshaman]

That is a bizarre reaction, and I speculate it has very little to do with any ambient light sensor, rather some circuity looseness which is causing the circuit to open or close depending on the energy of the light hitting it.

As long as you're happy with it that's fine. But I'd be worried this is a symptom of a problem that could get worse over time, and the light may not turn on down the road in various random situations when you are expecting it to turn on.

Fortunately my light behaves as its expected to, or I'd have to send it back for warranty repair / replacement. A light not turning on when I press the "on" button is not something I could live with.

I mentioned elsewhere or above that this has been found in another type of light and was determined to be the LED putting a voltage into the circuit. LED's DO create a voltage output if there is enough light on them. Personally I think it's cool enough to be called a feature - and orcinus is just lucky to be one of the few with it. I'd probably hang on to it but if anything else got strange I'd see about sending it back.

 

[matrixshaman]

BTW - got mine today - this light is AMAZING in so many ways. :twothumbs
to Khoo and Liteflux!

 

[TooManyGizmos]

:naughty: .. I really think some of you guys are just *Tapping* your button to quickly. Slow down and push it more deliberatly and firmly on the first turn-on push. See if that clears up the *NO response* on the first push.

Ooooooh-kaaaaaay... This is getting SERIOUSLY weird and a bit spooky. :duh2:

It seems my LF5XT either has a mind of it's own or a different firmware than the rest of them.

I've just noticed mine has an accidental-click avoidance function of some sort built in. If i don't do anything with it (i.e. leave it off) for 15 seconds or more (i've timed it many times - it's EXACTLY 15 seconds), it takes ONE click to "unlock" it, then a SECOND click to switch it on. If you wait for 15 seconds between the "unlock" and switch-on, it re-locks.

100% burst (PH) from off, random strobe (C+PH) from off and momentary mode override the "feature", as expected. Which would lead me to believe it's not a bug, but an intentional feature.

Mine , Also , won't respond if I just *TAP* it ...... but WILL turn on the first time if I firmly press/release . It seems to need .2 of a second to get the turn-on signal in the MCU.

Please try it and see if it helps .

.

 

[orcinus]

Already tried it, the "firmness" or press duration don't do anything. In fact, if you keep it pressed too long, it rejects the keypress (try it - press it longer than you usually do, but not long enough for the PH - somewhere in between).

Like i wrote, the only variables that seem to affect it are the amount of time elapsed from the last action and the amount of ambient light (that last one is probably limited to my particular sample).

 

[TooManyGizmos]

. Must be the variable tolerances in electronic components. Kinda like resistor values which vary + or - .

Most are not the exact resistance value stated.

I hope Khoo gets a definitive answer on this from LiteFlux real soon - it needs to be investigated & understood.


just tryin to help
.

 

[04orgZx6r]

hmmm......I think I need to see a vid of this LF5 XT "spookiness" how bout it orcinus?

 

[orcinus]

The sun's going down at the moment, so i'll see what i can do tomorrow...

 

[orcinus]

--- ignore ---

(false alarm)

 

[LED-holic]

It's ALIVE!!!!!!!!!!!!!!!!!

Run fer yer life!!!!!!!!!!!

:huh::tinfoil::duck::duck::eeksign:

 

[orcinus]

Here's a vid of the sunshine-lockout bug, per request:
http://www.youtube.com/watch?v=CRBROuLc6UU

While it's pointed toward the sun (it was shining through some clouds) i'm clicking like crazy, pressing and holding etc. to show nothing happens. Then i press and hold, rotate it away from the window and into the shade (still holding the button) and the moment it goes from sunshine to shade, it switches on.

Re: 15-second lockout - i took out the switch assembly, cleaned it up, lubed the button o-ring slightly and reassembled everything (scratching the brass retention ring in the process a bit, because it got stuck at one point and my screwdriver slipped). A firm, slightly longer and more determinate click now always seems to switch it on.

I feel a bit bad about scratching up the ring a bit (purely cosmetic damage), even though you can't see it without dismantling the light. I'm a tad too obsessive sometimes... :shrug:

 

[WadeF]

orcinus, looks like you're clicking it too fast, all you will do is turn it on and off and on and off. It may never come on. If you click, click you turn it on and off and it will be off before it can come on due to the 0.4 sec delay.

Try pointing it at the sun, give it one firm click and wait. If nothing happens, give it another firm click and wait.