Protocol Interfaces


A tiny USB to I²C bridge that is compatible with I²CDriver

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I²CMini is a USB to I²C bridge. It can drive and monitor I²C traffic and measures just 18 mm square. It has a micro USB connector, a Qwiic connector on the I²C side, and .1" pins for a breadboard or pin header. I²CMini is 100% compatible with I²CDriver, and like I²CDriver ( it’s an easy-to-use, open source tool for controlling I²C devices. It has a GUI that works with Windows, Mac, and Linux, and it has first-class Python2/3, C/C++, and command-line tools.

I²CMini is particularly well-suited for applications like IoT and drones, cleanly separating your SBC from the I²C bus. Because it is totally compatible with I²CDriver, you can develop on the I²CDriver and deploy on the I²CMini.

Like I²CDriver, it works equally well with Windows, Mac, and Linux. It uses a standard FTDI USB serial chip to talk to the PC, so no special drivers need to be installed. The board includes a separate 3.3 V supply for your I²C sensors and peripherals.

On the I²C side, I²CMini has the same four-pin header for connecting to peripherals as the I²CDriver. You can solder directly to this .1 " header. It also offers a Sparkfun Qwiic-compatible connector. Qwiic is a new standard for building I²C networks without soldering.

I²CMini comes with free (as in freedom) software to control it from:

Like I²CDriver, it can both drive and listen on the I²C bus, and it has the same programmable pullup resistors for both I²C lines.

Who Needs It and Why?

If you want to connect an I²C peripheral to a CPU with USB, I²CMini is the ideal interface. Its straightforward Open Source hardware and software design make it the maker’s choice.

Show I²C Devices Who’s Boss

By controlling I²C hardware using the PC tools you’re most comfortable with, you can get devices doing what you want in a fraction of the development time. Calibrating devices like accelerometers, magnetometers, and gyroscopes is much easier when done directly on the PC.

I²CMini ships with Python examples using small groups of I²C devices to make something useful.

A Tiny Bridge

At 2.1 g and 18 x 18 mm, the I²CMini will fit into the tinyiest projects, so after developing on the full-size I²CDriver, you can drop the I²CMini into small spaces like drones and IoT devices.

A Solid Platform for Your Embedded I²C Network

Because it uses the same proven firmware and toolchain as I²CDriver, I²CMini is the solid, reliable choice for driving your sensors and peripherals. Its a straightforward interface - it appears as a standard serial device - giving you a high level of portability and maintainability. There are no special drivers to install, so code for I²CMini and I²CDriver can work on any platform.

Compare: I²CDriver and I²CMini




ToolOpen hardware / softwareAdditional sensorsNo driver installHost softwarePrice (USD)
I²CMini Yes Core temperature Yes GUI, command-line, Python, C/C++, and flashrom $25
Totalphase AardvarkNoNoneNoCommand-line, Python, C/C++$300
FTDI MPSSE cableNoNoneNoC/C++$27.30
Bus PirateYesInputYesCommand-line. Python, flashrom$27.15

I²CMini Products

I²CMini Core

I²CDriver Core

The "Core" package is an I²CMini with a Qwiic connector cable.

I²CMini Expert

I²CDriver Expert

The "Expert" package is for makers building serious I²C sensing and control applications. It includes three I²CMini modules with Qwiic connector cables, and a selection of input and output I²C modules from Electric Dollar Store:

plus two carrier PCBs for permanently mounting the modules.

I²CMini Gold

I²CDriver Gold

The "Gold" package is even more extensive. It includes three I²CMini modules with Qwiic connector cables and a complete line of 20 I²C modules from Electric Dollar Store :

plus four carrier PCBs for permanently mounting the modules.

In the Press

"Tiny USB bridge board helps tame I2C traffic"

Hackster News

"the ultra-compact I²CMini is a great companion to Excamera's earlier I²CDriver."

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Produced by Excamera Labs in Pescadero, CA.

Sold and shipped by Crowd Supply.

I²CMini Core

An I²CMini with a Qwiic cable.

$25 $8 US Shipping / $18 Worldwide

I²CMini Expert

Three I²CMinis, three Qwiic cables, six I²C modules, and two module carrier boards.

$49 $8 US Shipping / $18 Worldwide

I²CMini Gold

Three I²CMinis, three Qwiic cables, 20 I²C modules, and four module carrier boards.

$69 $8 US Shipping / $18 Worldwide

About the Team

Excamera Labs

I'm dedicated to building useful hardware and software, particularly where embedded systems meet graphics and imaging. Probably my best known public projects are the Gameduino series of game accessory boards, and the J1 CPU. I have benefited immensely from Open Source hardware and software, so I try to open source as much as I can.

James Bowman


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