Controling the Camera "flash" LED

[JohnHind]

Does anyone know of a utility to directly switch on and off the white LED used as camera flash on the TyTn? It strikes me that this would make a great flashlight (torch) if it could be easily switched on and off from a today screen launcher icon or from a hard key assignment.

I know you can switch it on by starting the camera utility and switching to movie mode (it comes on immediately, you do not actually have to start recording a movie), but that takes too long when you are fumbling in the dark!

[vijay555]

VJCandela.

V

[JohnHind]

Many thanks. Small donation on the way - do not spend it all at once!

Why do you say prolonged use will cause damage? It looks like an LED to me, which should have long service life. Admittedly for the still camera, electronics could be rated for flash use only due to thermal reasons, but it comes on for longer times when recording video. If rated for more than a minute or so continuous use, I'd expect it to last for the lifetime of the LED.

[vijay555]

Yeah, we've had discussions about this, and although I've never had problems with it, others have burnt out their leds after prolonged periods (> 1 min I guess).

I use an automatic timeout after 30 seconds.

We're not sure why the LEDs can burn out, possibly they're being driven to an extra bright setting, or only rated for flash use on a pulse basis.
The led can actually go even brighter, but it's not worth it for the risk.

V

[JohnHind]

Sorry Vijay, I ran into a small problem.

I was hoping to assign this to a hardware button (long press of the camera button using Vito ButtonMapper), with a toggle action. However, except for -on and -off, all the command modes seem to require the button to be held down for the light to stay on. Even with the no-parameter version, the screen window dissapears again when I release the button.

Is this behaviour intentional? If so, would it be possible to have a -tog switch such that if the LED is off, it switches it on, if on off?

[vijay555]

I think this was intentional, so that you couldn't accidentally leave it on.
However, which version are you using, the full version or VJCandelaLite?

I think the lite version offers specific command line options, but even then, I think the auto off was intentional.

V

[JohnHind]

I tried all the installed shortcuts, including VJCandelaLite. With the exception of VJCandela On and Off, they all switch the LED off as soon as the button is released. Interestingly this behaviour is different if you just tap the shortcut in Programs. In this case, generally the LED stays on for a 30 second timeout. There must be some fancy programming here to detect it's started from a button?

VJCandella On does not seem to have a timeout (or it's too long for my patience!), but problem with this is you'd need to assign another button to the Off function, hence my suggestion of a toggle. I'd be happy with a timeout on it though, but not with having to hold the button pressed all the time.

I did a quick test using the camera app supplied with the TyTn - you can switch the LED on in video mode and it times out after 2 minutes, so HTC clearly regard it as safe to run it this long.