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.
How Lithium Polymer Batteries are Made
We got the opportunity to tour the Great Power Battery factory. Checkout how LiPos are made!
ESP8266 Powered Propane Poofer
Learn how Nick Poole built a WiFi controlled fire-cannon using the ESP8266 Thing Dev Board!
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.
TPL5110 Nano Power Timer Hookup Guide
The TPL5110 Nano Power Timer is ideal for applications that require low power, and especially those projects that are running off of a LiPo battery. The Nano Power Timer will turn on your project after the set amount of time, continuously.