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 to Power a Project
A tutorial to help figure out the power requirements of your project.
ESP32 Thing Power Control Shield Hookup Guide
This tutorial shows you how to get started with the ESP32 Thing Power Control Shield.
LuMini 8x8 Matrix Hookup Guide
The LuMini 8x8 Matrix (APA102-2020) are the highest resolution LED matrix available.
MicroMod Ethernet Function Board - W5500 Hookup Guide
Add Ethernet and PoE capabilities to your MicroMod project using the Ethernet Function Board - W5500.