This is a useful project to build a small power meter using a Pro Trinket, an OLED display, and the INA219 current sensing breakout.  You can use this power meter to measure the voltage, current, power, and milliamp-hours of current that are used by a device.  Why are these measurements useful?  If you're estimating how long a device might run on batteries or if it's possible to run off small solar cells then you'll have to know how much power the device uses.  This power meter project is perfect for connecting to a project or device to measure its power consumption and estimate how long it will run on batteries!

Before you get started you'll want to be familiar with the basics of using an Arduino & the Arduino IDE.  You'll also need to do a little soldering to connect headers to the components used in the project.

Continue on to learn about the hardware used in the project, and how to wire it together.