Water the tree – there’s an app for that?

Well no, but [Chris] needed something to remind him when to water the tree. Most folks would use their nifty iPhone to set up a calendar reminder, but why do that when you can purpose a 32 bit microcontroller to do it for you?

To detect a falling water level [Chris] attached a two-pin header to the end of a clothes pin clipped to the side of the tree stand. When the water level is covering the pins it completes a circuit, verified by a measurable current. When the water level drops the mbed microcontroller detects the loss of conductivity and through some creative code sends out an email and SMS reminder.

If you’re in love with your iPhone but not your living things, this will keep that tree kicking until after the new year.