This project has been done many times, so I won’t go into much detail. I wanted a general purpose notifier, especially once I built Laundrymon. I figured a box with a high powered RGB LED and an XBee would fit the bill. The enclosure is just a project box with a sheet of cheap copy paper shaped with some wire and hot glue. I added a photoresistor to dim the light in the bedroom at night.
I’m building a couple of these to scatter throughout the house so I always know when the laundry’s done, an email arrives, or whatever else I might want to be notified about.
Important note: I misplaced one of the capacitors when designing the board. It seems to be running well enough with a wire in its place. It’s the one on the right in the lower left corner, above the power connector.