Adafruit Feather 32u4 Adalogger

Adafruit Feather 32u4 Adalogger combines USB, battery charging, and a built-in microSD cardholder, making it an easy, portable solution for Arduino-based data logging projects.

Feather is Adafruit’s lightweight, portable development board family—thin, compact, and designed to power projects you can take anywhere. Built to be a new standard for mobile microcontroller platforms, Feather combines USB connectivity, battery support, and a consistent form factor across the range.

The Adafruit Feather 32u4 Adalogger is Adafruit’s take on an all-in-one datalogger (or data reader). It’s based on the Feather 32u4 and adds a built-in microSD cardholder, making it ready for logging sensor data or reading files straight out of the box.

At its core is the ATmega32u4, running at 8 MHz with 3.3 V logic—the same proven setup used on the Adafruit Flora. The chip provides 32 KB of flash and 2 KB of RAM, along with native USB support. This means no external USB-to-serial chip is needed, and the board can also act as a USB HID device, such as a mouse, keyboard, or USB MIDI controller.

Designed with portability in mind, the Feather 32u4 Adalogger includes a JST connector for 3.7 V lithium polymer batteries and onboard battery charging. It can run directly from the micro USB connector, from a battery, or automatically switch between the two when USB power is available. The battery voltage is routed through a resistor divider to an analogue pin, allowing you to monitor battery levels and know when it’s time to recharge.

The extra board space is used to add data-logging essentials:

• MicroSD cardholder for reading or writing large amounts of data
• Green LED on pin #8 for status indication or simple debugging

The board ships fully assembled and tested, with a USB bootloader pre-installed for quick use with the Arduino IDE. Header pins are included but not soldered. LiPo battery, microSD card, breadboard, JST cable and USB cable are not included.

Features

• ATmega32u4 @ 8MHz with 3.3V logic/power
• 3.3V regulator with 500mA peak current output
• USB native support, comes with USB bootloader and serial port debugging
• You also get tons of pins - 20 GPIO pins
• Hardware Serial, hardware I2C, hardware SPI support
• 7 x PWM pins
• 10 x analogue inputs
• Built in 100mA lipoly charger with charging status indicator LED
• Pin #13 red LED for general purpose blinking
• Power/enable pin
• 4 mounting holes
• Reset button

Specifications

• Measures 51mm x 23mm x 8mm - without headers
• Weight - 5.1 grams

Revision History

• As of July 26, 2023 – We've updated this PCB with Adafruit Pinguin to make a lovely and legible silkscreen - you may get the new PCB or the older version with vector fonts - both are identical other than the fancy silkscreen.

Resources

• Datasheet
• Tutorial

Package Contents

• 1x Adafruit Feather 32u4 Adalogger
• 2x 16-pin headers