Reducing Arduino Power Consumption
Contributors:
Alex the Giant
Alex the Giant 
Resources and Going Further
More information on low-power modes and options can be found in the datasheet for the 328P.
For more power-related fun, check out the following SparkFun tutorials.
Sunny Buddy Solar Charger V13 Hookup Guide
How to hookup the Sunny Buddy: a solar-powered, MPPT (peak-power tracking), LiPo battery charger.
Hobby Servo Tutorial
Servos are motors that allow you to accurately control the rotation of the output shaft, opening up all kinds of possibilities for robotics and other projects.
Single Supply Logic Level Converter Hookup Guide
The Single Supply Logic Converter allows you to bi-directionally translate signals from a 5V or 3.3V microcontroller without the need for a second power supply! The board provides an output for both 5V and 3.3V to power your sensors. It is equipped with a PTH resistor footprint for the option to adjust the voltage regulator on the low side of the TXB0104 for 2.5V or 1.8V devices.
TSH82 Configurable OpAmp Hookup Guide
The TSH82 Configurable OpAmp board offers the designer a great balance of performance and flexibility. We'll show you how to get the very best out of your board!