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.
Uh-Oh Battery Level Indicator Hookup Guide
Learn how to assemble and use the TL431 in the Uh-Oh Battery Level Indicator Kit.
What is a Battery?
An overview of the inner workings of a battery and how it was invented.
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.
Qwiic Quad Relay Hookup Guide
SparkFun’s Qwiic Quad Relay is a product designed for switching not one but four high powered devices from your Arduino or other low powered microcontroller using I2C.