# Pro Trinket Power Meter ## Overview ![](https://cdn-learn.adafruit.com/assets/assets/000/129/457/medium800/trinket_stemma-circuit.png?1713899754) This is a useful project to build a small power meter using a [Pro Trinket](https://www.adafruit.com/product/2000), an [OLED display](https://www.adafruit.com/products/931), and the [INA219 current sensing breakout](https://www.adafruit.com/products/904).  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](../../../../lesson-0-getting-started/overview).  You'll also need to [do a little soldering](../../../../adafruit-guide-excellent-soldering/tools) 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. - [Next Page](https://learn.adafruit.com/pro-trinket-power-meter/hardware.md) ## Featured Products ### INA219 High Side DC Current Sensor Breakout - 26V ±3.2A Max [INA219 High Side DC Current Sensor Breakout - 26V ±3.2A Max](https://www.adafruit.com/product/904) This breakout board will solve all your power-monitoring problems. Instead of struggling with two multimeters, you can just use the handy INA219 chip on this breakout to both measure both the high side voltage and DC current draw over I2C with ±1% precision. **Please...** In Stock [Buy Now](https://www.adafruit.com/product/904) [Related Guides to the Product](https://learn.adafruit.com/products/904/guides) ### Adafruit Pro Trinket - 5V 16MHz [Adafruit Pro Trinket - 5V 16MHz](https://www.adafruit.com/product/2000) **Deprecation Warning: The Pro Trinket bit-bang USB technique it uses doesn't work as well as it did in 2014, many modern computers won't work well. So while we still carry the Pro Trinket so that people can maintain some older projets, we no longer recommend it.** Please... In Stock [Buy Now](https://www.adafruit.com/product/2000) [Related Guides to the Product](https://learn.adafruit.com/products/2000/guides) ### Adafruit Pro Trinket - 3V 12MHz [Adafruit Pro Trinket - 3V 12MHz](https://www.adafruit.com/product/2010) **Deprecation Warning: The Pro Trinket bit-bang USB technique it uses doesn't work as well as it did in 2014, many modern computers won't work well. So while we still carry the Pro Trinket so that people can maintain some older projets, we no longer recommend it.** Please... No Longer Stocked [Buy Now](https://www.adafruit.com/product/2010) [Related Guides to the Product](https://learn.adafruit.com/products/2010/guides) ### Monochrome 128x32 I2C OLED graphic display [Monochrome 128x32 I2C OLED graphic display](https://www.adafruit.com/product/931) These displays are small, only about 1" diagonal, but very readable due to the high contrast of an OLED display. This display is made of 128x32 individual white OLED pixels, each one is turned on or off by the controller chip. Because the display makes its own light, no backlight is... No Longer Stocked [Buy Now](https://www.adafruit.com/product/931) [Related Guides to the Product](https://learn.adafruit.com/products/931/guides) ### Monochrome 0.96" 128x64 OLED Graphic Display - STEMMA QT [Monochrome 0.96" 128x64 OLED Graphic Display - STEMMA QT](https://www.adafruit.com/product/326) These displays are small, only about 1" diagonal, but very readable due to the high contrast of an OLED display. This display is made of 128x64 individual white OLED pixels, each one is turned on or off by the controller chip. Because the display makes its own light, no backlight is... In Stock [Buy Now](https://www.adafruit.com/product/326) [Related Guides to the Product](https://learn.adafruit.com/products/326/guides) ### Half Sized Premium Breadboard - 400 Tie Points [Half Sized Premium Breadboard - 400 Tie Points](https://www.adafruit.com/product/64) This is a cute, half-size breadboard with 400 tie points, good for small projects. It's 3.25" x 2.2" / 8.3cm x 5.5cm with a standard double-strip in the middle and two power rails on both sides. You can pull the power rails off easily to make the breadboard as... In Stock [Buy Now](https://www.adafruit.com/product/64) [Related Guides to the Product](https://learn.adafruit.com/products/64/guides) ### Breadboarding wire bundle [Breadboarding wire bundle](https://www.adafruit.com/product/153) 75 flexible stranded core wires with stiff ends molded on in red, orange, yellow, green, blue, brown, black and white. These are a major improvement over the "box of bent wires" that are sometimes sold with breadboards, and faster than stripping your own solid core wires. Makes... In Stock [Buy Now](https://www.adafruit.com/product/153) [Related Guides to the Product](https://learn.adafruit.com/products/153/guides) ### USB cable - USB A to Micro-B [USB cable - USB A to Micro-B](https://www.adafruit.com/product/592) This here is your standard A to micro-B USB cable, for USB 1.1 or 2.0. Perfect for connecting a PC to your Metro, Feather, Raspberry Pi or other dev-board or microcontroller Approximately 3 feet / 1 meter long In Stock [Buy Now](https://www.adafruit.com/product/592) [Related Guides to the Product](https://learn.adafruit.com/products/592/guides) ## Related Guides - [CircuitPython Hardware: SSD1306 OLED Display](https://learn.adafruit.com/micropython-hardware-ssd1306-oled-display.md) - [Pro Trinket Tachometer](https://learn.adafruit.com/pro-trinket-tachometer.md) - [Wireless Game Show Poppers for the Classroom!](https://learn.adafruit.com/wireless-game-show-poppers.md) - [OLED TRON Clock](https://learn.adafruit.com/oled-tron-clock.md) - [Adafruit Arduino IDE Setup](https://learn.adafruit.com/adafruit-arduino-ide-setup.md) - [Adafruit FT232H With SPI & I2C Devices](https://learn.adafruit.com/adafruit-ft232h-with-spi-and-i2c-libraries.md) - [Adding Third Party Boards to the Arduino v1.6.4+ IDE](https://learn.adafruit.com/add-boards-arduino-v164.md) - [Your Pulse Displayed with NeoPixels](https://learn.adafruit.com/pulse-sensor-displayed-with-neopixels.md) - [Pro Trinket Rotary Encoder](https://learn.adafruit.com/pro-trinket-rotary-encoder.md) - [I2C Addresses and Troublesome Chips](https://learn.adafruit.com/i2c-addresses.md) - [Adafruit INA219 Current Sensor Breakout](https://learn.adafruit.com/adafruit-ina219-current-sensor-breakout.md) - [4x4 Rotary Encoder MIDI Messenger](https://learn.adafruit.com/4x4-rotary-encoder-midi-messenger.md) - [3D Printed Daft Punk Helmet](https://learn.adafruit.com/3d-printed-daft-punk-helmet.md) - [Ray Gun Blaster](https://learn.adafruit.com/ray-gun-blaster.md) - [Adafriend the Virtual Pet Cube](https://learn.adafruit.com/adafriend.md)