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.
Electric Power
An overview of electric power, the rate of energy transfer. We'll talk definition of power, watts, equations, and power ratings. 1.21 gigawatts of tutorial fun!
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.
LumiDrive Hookup Guide
The LumiDrive LED Driver is SparkFun’s foray into all things Python on micro-controllers. With the SparkFun LumiDrive you will be able to control and personalize a whole strand of APA102s directly from the board itself.
Buck-Boost Hookup Guide
This tutorial shows you how to hook up and use the SparkFun Buck-Boost board.