Wow, I haven't though that someone not participating in mentioned Lanterne discussion/hecking sources would notice that. Respect

In a nutshell, indeed, there are two modes. The "basic" one, as used for all torch applications, got lesser maximum brightness value (due to lesser current), but is able to perform 100% duty cycle (aka "just be turned on"). The "flash" mode is much more powerful, but available only in duty cycles (with maximum one around 75% IIRC, but don't quote me on that - details in the already mentioned Lanterne link provided by pichlo), and rightly so, as using it on 100% would damage leds pretty quickly.

Now, for the purpose of program proposedd here, only the "torch" mode is approriate, as I don't think that stroboscopic effect is good for a healthy sleep/awakening (unless someone want to simulate dawn in a hurricane-hit forest, with light passing through shaking branches/leaves).

Why? "Dimming" (to be precise, changing current in a steps, in our case) is neutral for a diode. AIUI [/b]pichlo[/b] meant leaving flash diodes turned on for a prolonged time, no matter what the brigtness level.

Here I disagree, BTW - my trusty N900 is helping me with various conservation tasks in not-so-easily-accessible places for years already, and I regularly leave flash diodes at maximum "torch" mode brightness for a hour or so, as it's lighting up my patient's internal organs workplace. Zero adverse effects observed - in fact, I've actually had some unpleasant surprises with other hardware components, and I guess that those leds (and their backscreen/keyboard counterparts) are the things that will be (amongst) longest living parts in N900's motherboard, no matter of (ab)use.

/Estel

// Edit

In fact, what you would like to achieve could be done with a rather simple script (written with help of Lanterne discussion and its documentation), executed by any alarm app that can trigger custom command on alarm.

Executing command on alarm would be, probably, a few lines of code in CSSU'ish alarm replacement (or update, I don't remember if it was open thing in vanilla). IIRC, freemangordon was the author of CSSU'ish latest version - it could be good idea to post a feature request in CSSU's bugzilla. If that part is done, you have 99% of work done.

/Estel

Otherwise, there should be, already available, "eggtimer" programs that can trigger custom commands, but setting them up for alarm clock job is more tedious (and less "clean") job than using Maemo's integrated alarm would be.