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.
Powering LilyPad LED Projects
Learn how to calculate how many LEDs your LilyPad project can power and how long it will last.
SparkFun 5V/1A LiPo Charger/Booster Hookup Guide
This tutorial shows you how to hook up and use the SparkFun 5V/1A LiPo Charger/Booster circuit.
IoT Power Relay
Using the ESP32 to make a web-configured timed relay.
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.