Lanterne is a small app for working with the LEDs used to create a flash for the N900's camera. At the moment, it supports "torch" mode (continuously light the LEDs at low power), and "strobe" mode (a quick flash of the LEDs at high power). Also, holding down the "strobe" button will cause the LEDs to flash continuously (a "strobelight" effect).

The LED power, the duration of the strobe, and the pause between strobes can be modified.

Warning: I am not an expert on the flash LEDs! Although I have made an effort to ensure that only safe values can be entered for these parameters, I cannot say for certain that this app will not damage your LEDs. Use with caution!

At this point, several features have been added:
* A Morse code flasher, allowing you to type in a message or load a text file to be transmitted. The dot duration is configurable.
* A continuous SOS beacon.
* A continuous pulse (essentially, Morse E rather than SOS).
* Support for use with the red (indicator) LED.

Lanterne now recognizes the status of the camera cover, and avoids turning on the LEDs if it is closed (and will turn off the LEDs if the user closes the cover). Also, it can now exit when the user closes the camera cover.

Version 0.5.6 has been added to the end of this post, as well as submitted to the extras-devel repository.

Lanterne is open-source software, released under the GPL version 2 (or greater). You can find the source code at Github:

https://github.com/jpietrzak8/Lanterne