This app controls the backlight and/or the Tail Light clip (if you can find one) allowing you to signal morse-code, use the Palm as a light or even flash like a metronome!

Bit cheeky but here's my video on adding a torch to your Palm using this software https://youtu.be/Le7DOMj9xk4

Freeware Compatible with OS2 Palm 3000 (though no baacklight on this model) and up