Reducing Arduino Power Consumption
Contributors: Alex the GiantFavorited Favorite 18
Reducing the Clock Speed
In projects where the Arduino doesn't need to execute a large number of instructions in a short amount of time or in projects where timing isn't an issue, reducing the clock speed of the microcontroller can shave a few milliamps off the supply current. For example, running the Arduino at 5V and reducing the clock speed from 16MHz down to just 8MHz can drop the current needed from 12mA down to ~8.5mA.
To better understand the relationship clock speed has with the microcontroller, let's look at the graph below.
As you can see, reducing the clock speed can triple the battery life. The trade off of course is that you won't be able to execute as many instructions per second, and for some applications, this solution isn't an option.