Reply
Thread Tools
Posts: 293 | Thanked: 76 times | Joined on Jan 2008 @ Fremantle, W. Australia
#21
The LED limits would be due to poor heatsinking.
If the LED junction gets too hot, it will be damaged. I suppose there is just enough heatsinking to allow 320mA for 500ms.
I'd like to see a Cree XLamp XP-E, bonded to a metal back-cover. Now that's a _real_ torch. Could do > 200 lumens in flash mode (brief direct-drive from the battery), and around 100 lumen from 1W in torch mode. (better than a 3D Maglite)
 

The Following 3 Users Say Thank You to myk For This Useful Post:
Posts: 87 | Thanked: 40 times | Joined on May 2007
#22
myk, what a nice explanation.
 
Posts: 4 | Thanked: 4 times | Joined on May 2009
#23
Originally Posted by sairon View Post
Doing a bit more researching I found that Rygel is slated for release with Harmattan, and Rygel seems to implement the functionality I'm interested in. So I'm going to cross fingers and hope that it's awesome
You don't really need to wait: http://live.gnome.org/Rygel/N900

Soon after the next software upgrade is available, installing rygel from maemo-extras will be very much possible.
 

The Following 2 Users Say Thank You to zeenix For This Useful Post:
Posts: 60 | Thanked: 21 times | Joined on Nov 2009
#24
Originally Posted by Flandry View Post

Edit: I'm sorry to report that whenever the camera app is active, the LEDs turn off, regardless of the setting of the flashlight applet. Still, a very handy little applet.
Switch flashlight off, open the camera app, swap to video mode, start recording, enable flashlight. It works for me!
 

The Following User Says Thank You to truslack For This Useful Post:
Flandry's Avatar
Posts: 1,559 | Thanked: 1,786 times | Joined on Oct 2009 @ Boston
#25
Originally Posted by truslack View Post
Switch flashlight off, open the camera app, swap to video mode, start recording, enable flashlight. It works for me!
Hahah ok, so that works. It's like breaking your front door down to get to your keys, but it works.
__________________

Unofficial PR1.3/Meego 1.1 FAQ

***
Classic example of arbitrary Nokia decision making. Couldn't just fallback to the no brainer of tagging with lat/lon if network isn't accessible, could you Nokia?
MAME: an arcade in your pocket
Accelemymote: make your accelerometer more joy-ful
 
Posts: 355 | Thanked: 566 times | Joined on Nov 2009 @ Redstone Canyon, Colorado
#26
http://gitorious.org/omap3camera/mai...d4f7122917e8ba

Code:
commit b3257216343f1f259f99335e3d64e5c0f210ab05
Author: Tuukka.O Toivonen <tuukka.o.toivonen@nokia.com>
Date:   Mon Aug 17 10:30:48 2009 +0300

    rx51: adjust LED flash constraints to prevent overheating
    
    - set LED flash maximum timeout to 500 ms in flash mode
    - set LED flash maximum current to 50 mA in torch mode
    - fix maximum current in flash mode which must be 320 mA
    
    Signed-off-by: Tuukka Toivonen <tuukka.o.toivonen@nokia.com>
 
Posts: 1,427 | Thanked: 2,077 times | Joined on Aug 2009 @ Sydney
#27
Originally Posted by Flandry View Post
jakiman, can your setup measure light delivered in a short pulse? I'm curious what the actual flash output compared to the continuous mode output is.
Only saw your question now. haha.

I just did a test of the flash during taking a photo in the same light box. I did it a few times and I was able to get around 80-95 lux for that instant. (compared to only around 23-25lux for flashlight torch mode)

That's nearly 4 times the output. To produce 4 times its output, it might need 6-8 times the power due to loss in efficiency. (eg. in high power LEDs, 1W might produce 100 lumens but it requires around 3W to produce 200 lumens)

So your calculations actually look pretty close. =)
 
Posts: 145 | Thanked: 80 times | Joined on Jan 2010
#28
I read through this whole thread, and I am still wondering whether it's possible to turn the camera LEDs on for light without invoking the camera app (i.e. no image preview shows). I've been in situations where a light would be very useful, but a camera is strictly forbidden.
 
Flandry's Avatar
Posts: 1,559 | Thanked: 1,786 times | Joined on Oct 2009 @ Boston
#29
Originally Posted by jakiman View Post
Only saw your question now. haha.

I just did a test of the flash during taking a photo in the same light box. I did it a few times and I was able to get around 80-95 lux for that instant. (compared to only around 23-25lux for flashlight torch mode)

That's nearly 4 times the output. To produce 4 times its output, it might need 6-8 times the power due to loss in efficiency. (eg. in high power LEDs, 1W might produce 100 lumens but it requires around 3W to produce 200 lumens)

So your calculations actually look pretty close. =)


Thanks for checking!

cyeung: You have to open the camera lens cover to expose the LEDs. You might be able to hack the device to not start the camera app when you do that, but isn't the actual opening of the lens cover on a camera going to be a bigger problem?
__________________

Unofficial PR1.3/Meego 1.1 FAQ

***
Classic example of arbitrary Nokia decision making. Couldn't just fallback to the no brainer of tagging with lat/lon if network isn't accessible, could you Nokia?
MAME: an arcade in your pocket
Accelemymote: make your accelerometer more joy-ful
 
Posts: 287 | Thanked: 165 times | Joined on Oct 2009 @ The Netherlands
#30
Originally Posted by cyeung View Post
I read through this whole thread, and I am still wondering whether it's possible to turn the camera LEDs on for light without invoking the camera app (i.e. no image preview shows). I've been in situations where a light would be very useful, but a camera is strictly forbidden.
We know what you mean For these situations, you can always get one of these:

http://failblog.files.wordpress.com/...oduct-fail.jpg

(nsfw)
 
Reply


 
Forum Jump


All times are GMT. The time now is 21:36.