SparkFun
SparkFun Qwiic OpenLog
The SparkFun Qwiic OpenLog is an I²C-based data logger that stores serial data to a microSD card. Based on the popular OpenLog, this version replaces the ser...
The SparkFun Qwiic OpenLog is an I²C-based data logger that stores serial data to a microSD card. Based on the popular OpenLog, this version replaces the serial interface with I²C and Qwiic connectors, allowing you to daisy-chain multiple sensors and log data without occupying your serial port.
Powered by an ATmega328 running at 16 MHz with the Optiboot bootloader, the Qwiic OpenLog is compatible with the Arduino Uno board setting in the Arduino IDE. It supports clock stretching for reliable data transfer, recording up to 20,000 bytes per second at 400 kHz I²C. Breadboard-friendly 0.1" header pins are also broken out for non-Qwiic setups.
Key Features
- I²C Data Logging – Log data from multiple I²C devices via Qwiic daisy-chain
- microSD Storage – Supports 64 MB to 32 GB cards in FAT16 and FAT32
- 20,000 Bytes/s – High-speed recording at 400 kHz with clock stretching
- ATmega328 Processor – Arduino Uno compatible (Optiboot bootloader)
- Qwiic Connectors – Polarised JST connectors for solderless I²C wiring
- Breadboard Friendly – 0.1" header pins broken out for traditional wiring
Specifications
- Microcontroller – ATmega328 @ 16 MHz
- Interface – I²C (Qwiic / 0.1" header)
- I²C Speed – Up to 400 kHz with clock stretching
- Max Logging Rate – 20,000 bytes/s
- microSD Support – 64 MB to 32 GB, FAT16/FAT32
- Idle Current – 2–6 mA
- Recording Current – 20–23 mA (varies with microSD card)
- Bootloader – Optiboot (Arduino Uno compatible)
Ideal For
- Sensor data logging and environmental monitoring
- Project debugging and black-box recording
- Scientific data collection
- Any I²C system requiring persistent storage
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- Bootloader
- Small starter software on a microcontroller that lets new code be uploaded before the main program runs. Knowing how to enter bootloader mode matters when you need to program the board or recover it after a faulty sketch.
- IDE
- Short for Integrated Development Environment, a program used to write, run and manage code. It matters because some learners prefer a traditional coding workspace instead of a guided notebook-style lesson.
- microcontroller
- A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
- microSD card
- A microSD card is a small removable memory card used to store files such as audio tracks. For this product, the card is where the sound files live, so its capacity and formatting can affect how many sounds you can use.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
Find this product in
Prototyping & Wiring
Qwiic OpenLog Schematic
Schematic · 65.7 KB · Click any page to view full size
Supplier page — sparkfun.com
Supplier Description · 599.4 KB · Click any page to view full size
Resources & Downloads
Guides, code examples, and more
Related Tutorials
Free guides on learn.littlebird.com.au
