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.
Connector Basics
Connectors are a major source of confusion for people just beginning electronics. The number of different options, terms, and names of connectors can make selecting one, or finding the one you need, daunting. This article will help you get a jump on the world of connectors.
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.
ATX Power Connector (4-Pin) Breakout Hookup Guide
Do you need to power a project with 12V and 5V from one wall adapter? The ATX power connector breaks out the standard 4-pin computer peripheral port for your 12V and 5V devices!