App turns on Camera Flash for use as Flashlight -- bad idea?Support

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  1. Johnny Cakes

    Johnny Cakes Well-Known Member

    There is an app in the market which is written just for the Moment that uses the camera flash as a flashlight -- essentially it turns on the camera flash. The app says not to use the flash "too long" or damage may occur, but the "too long" time period is not defined.

    First, will having the flash on for an period of time damage it?

    Second, if so, any idea what maximum period of time would be "safe?"

  2. Radical-J

    Radical-J Well-Known Member

    I use it but only for 2-3 seconds. I don't want to be the guy that says yeah, don't use it beyond x seconds.

    Or you could think about how many times it would be used if you were continuously taking pics using the flash...
  3. AlkiDweller

    AlkiDweller Well-Known Member

    The original thread about this app is called Flashlight App for Moment and it's currently at the top of the fourth page. There's a lot of posts and I don't think anyone has had a problem so far.
  4. Tyrahn

    Tyrahn Well-Known Member

    The primary concern would be heat. The Moment does not have a very large LED, but it is packed in pretty close to a plastic lens. If you have it on for a decent length of time touch the flash every so often to make sure it's not getting very hot - if it's uncomfortable to touch it's been on too long.

    I would guess you could leave the LED on for a minute or two, but I'm just guessing there.

  5. IOWA

    IOWA Mr. Logic Pants Moderator

    Im assuming it would have to be a somewhat long time, as the camcorder uses the flash continuously....
  6. CriticalCritic

    CriticalCritic Well-Known Member

    My biggest concern is battery drain, and my Moment agrees with me. Last night I had just hit the yellow warning on my battery meter, and then I needed to use the flashlight app to clean out some stuff from a car that had been loaned to me. I had the light on for maybe a minute, then turned it off for about a minute, then ran it again for less than one more minute (both uses were with the light on 'high' brightness mode). After those two uses my battery meter was on critical (the battery with the red slash through it) and was about to crap out!

    Then I restarted my phone, and of course the battery meter jumped right back up into the yellow and lasted for at least another 90minutes longer (when I finally got around to plugging it in).

    So, because the battery jumped from yellow straight to critical (completely skipping red) it's apparent that the phone rapidly changed its battery remaining estimates to reflect the huge increase in consumption. Now my question is... can you hurt a battery by draining it too quickly?
  7. Tyrahn

    Tyrahn Well-Known Member

    Again, the concern is heat. Simply discharging a battery, however quickly, will not harm it in anyway (well, technically, over-discharging a battery can permanently damage it, but the "fuel gauge" in nearly all modern Li-ions prevent that). As you discharge any battery the chemical reacting creating power as well as resistance in internal conductors cause the battery to heat up - the faster the discharge the faster the the battery gets hot. Like with the LED, if the back panel of the phone ever gets too hot to comfortably hold, stop what you are doing.

    The Moment does have the ability to detect the battery's temperature (and you can monitor it with Spare Parts), so it may actually have some kind of self-protection mode that will either shut down the phone or certain services if the battery gets too hot. This is pure conjecture on my part though.

    As far as I know the Moment does not directly take currant drain rate into consideration when determining battery level (like some laptops do), the battery state is purely a reflection of current battery voltage. What you saw would have been created by a sudden voltage drop in the battery caused by a high load. Restarting the phone simply gave the battery time to recover, which it would have done nearly as well with the phone turned on. Depending on what battery code you are using (stock CJ05 or Cl14 kernels vs zefie's kernel) you may have actually been able to leave the phone on and see the battery meter go up back to yellow.

    I generally keep on the low intensity setting, it's normally bright enough for my needs and easier on the battery. If I need a brighter light for longer, I get a real flashlight :)

  8. Thefoodman52

    Thefoodman52 Well-Known Member

    I've left it on high-intensity and propped my phone up against my bed so I could see under my computer desk and re-wire everything to get rid of my rats nest. It was on for about 20 minutes... not one problem to date. I don't feel it's a big concern, as long as you don't use it as the lighting for your house or something.
  9. gentlefury

    gentlefury Well-Known Member

    it's an led....they barely use any electricity and produce little to no heat. There is no logical reason that using it as a flashlight could in any way damage your device.

    Ever seen the led keychain lights? They are extremely bright and they run off a watch battery for months.
  10. jvrobert

    jvrobert Well-Known Member


    I'm the author of the momentflash app, but I'm by no means an expert on the hardware or possible repercussions of using the flash too much.

    A few people in the reviews mentioned they did something to their flash, but then again some of the people who write reviews can barely read (e.g. "Durr, this didn't work on my Droid!"), it seems, so who knows if it's true ;) I tend to doubt it.

    The warning is mostly so people don't come bitch at me if they do happen to damage the LED. My guess is under normal use you'll absolutely be fine especially with "normal" mode (after all, this is what the video camera mode does - turn on the flash and leave it on), but it wasn't designed for "super bright" mode to be used all that much so I'd be careful on bright mode.
  11. Tyrahn

    Tyrahn Well-Known Member

    Not to sound like as asshole or anything, but both of those statements are completely false.

    In small, extremely low power LEDs (such as those used as indicator lights), power consumption and heat are negligible - but so is illumination. When you start talking about LEDs that create enough light to see by, both power consumption and heat begin to become much more noticeable. Your phone's screen is the single largest power-draw and becomes warm to the touch after it's been on for a while primarily because of screen's LEDs. In high-power applications LEDs are just now being developed that are more power efficient than florescent lights, most common LEDs draw about twice as much power as a florescent light of equal brightness.

    I have a flashlight that uses an advanced Cree white LED, it draws 5W of power to create 100 Lumens of light, and it gets very hot after extended use.

  12. edp

    edp Well-Known Member

    Thanks so much for the app! It works.
  13. latinmaxima

    latinmaxima Well-Known Member

    I use the regular and bright mode often and other than the battery draining more quickly then regular mode it doesn't seem to get hot nor fail at all. If I plan on using it for a long time I hit end to turn off the screen. Otherwise the screen is on I have no issues.

    On another note: Can we get a mod to merge this with the original thread. I think these are good concerns but should continu to remain with that thread.
  14. IOWA

    IOWA Mr. Logic Pants Moderator

    Check your private messages.

    Also, GREAT APP!
  15. ovrrdrive

    ovrrdrive Well-Known Member

    My last two Samsung phones had this feature built into them and it stayed on about 8-10 seconds when you activated it. I used it all the time and never had any problems. While I do think the led will generate some heat I don't see it being so much that a phone designed for outdoor use will be affected by it. As for power consumption, why the hell do you think they use led's in the first place?

    I didn't know an app was out yet that enabled this. I'm going downloading. :)
  16. Cirga

    Cirga Well-Known Member

    I use the LED MomentFlash app constantly at work. Its better than my real flashlight (which is not LED). I have used it for up to an hour on the first click setting. I noticed before that when I left it on the second intensity it would actually show my battery was dead within a few minutes.. but i would reset my phone and it would read the battery as full again. It was strange.. so I just used the first click setting.

    I havent had a problem at all other than that. Now that I have the CL14 update.. I will try using the higher intensity more often to see if it still drains.
  17. ramiss

    ramiss Well-Known Member

    Can anyone explain why, after a reboot, I have to click the widget twice to get the LED to come on at all? This happened before and after I rooted and wiped the OS.
  18. Cirga

    Cirga Well-Known Member

    It has always worked this way for me using the widget. The first tap does nothing, and the second turns it on. After I turn it on and off once, it no longer needs that first tap. maybe the first time loads it into running programs?
  19. jvrobert

    jvrobert Well-Known Member

    Yeah, I just noticed this too. I'll take a look soon and post a fixed version, it's something minor.
  20. jvrobert

    jvrobert Well-Known Member

    OK, this should be fixed as of version 1.02 of momentflash (on App market now).

  21. Jax63

    Jax63 New Member

    I use my flashlight app when I take my dogs out in the morning as it is dark. Our trip outside typically lasts 15 or so minutes and I haven't experienced any particular problems using it that length of time. I hope this helps.:)

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