I have been known to use it after dark...
I have a terrible memory..
I now have a dead battery.
Yep, everyone's done it. Left their lights on when they turn off their car or truck. Fortunately, most have an alarm that will go off to let them know what they've done. Not so much for my Ford. My F150 is less a fully formed vehicle than someone's attempt at a junkyard reconstruction. Let's just say it's a great yard truck with a bit of mystery.
The wife and I were out kayaking the other weekend. Out before dawn, it was easy to see that I had left my lights on when we were getting the kayaks unloaded. On the way home there was a bit of fog but otherwise daylight. Turned on the lights for safety. Arriving home we unloaded, cleaned up and left the lights on to fully drain the battery - just for good measure.
Sooooo, after a new battery and day of kicking my own posterior I went online to try and find a 3rd party headlight alarm. Either they aren't making them as much as they used to or my Google skills have diminished. Either way, I was not finding what I was looking for and I knew if i relied on my own memory I might as well just put aside the money for a new battery now.
I really wanted a battery alarm so I sat myself down with a pen and paper and started sketching out some ideas. How the alarm would be powered, what would control when it would and wouldn't go off, etc. Once I had a working idea I stopped by my local Hack Shack and picked up just a few items. Those, along with my standard stock of wires and do-dads, I was all set!