[platz]

Would it be possible to use something like an attiny2313 or even an attiny45, do the job of handling the reed switch data and then delegating the rest of the logic to a central server? I would think you'd get the most power savings that way.

[tonyd256]

The ATMega328P is pretty low power. I could probably save a bit more with a smaller more targeted MCU, but I wanted this board to be as close to the Arduino Uno as possible. I'm not sure what you mean by a central server. It's possible to use an ATTiny series chip to sense the reed switches and transmit to the nRF24 board.

[austinz]

Many families of uCs (e.g. MSP430) are extremely power-efficient. Power consumption is dominated by the radio; the fewer packets the better.