Video ports on laptops, desktops and SBCs have I2C on them. It's typically not easily accessible to hobbyists, but with this adapter, it's on pin headers! This means that, when booted into Linux, you can connect I2C devices directly to your laptop. You can run Raspberry Pi I2C device drivers on your laptop, you can reuse MicroPython drivers with minimal modifications, you can write Python, C or ${OTHER_LANGUAGE} code to interface with your devices, and you can use in-Linux-kernel I2C device drivers.

With this adapter, you can connect I2C GPIO expanders, program I2C EEPROMs, control I2C motor drivers, read I2C sensors - all of that without an intermediary Arduino/ESP**/STM/whatever. The adapter has three-row pin headers, so you can connect up to 3 devices, more if you daisy-chain devices somehow. I should have added a QWIIC socket but forgot about it - it will be added in the next revision, as soon as this batch of 10 sells out!

This adapter supports both 3.3V and 5V devices, all you need to do to switch from one to the other is to flip a switch (not pictured but will be present on the boards you get). The video port has 5V on it and the I2C signals are also 5V, but this adapter has onboard voltage regulation and level-shifting. If you replace the 3.3V regulator with an 1.8V one, you'll be able to interface with 1.8V devices instead!

This adapter also exposes some signals that might help you explore your computer's video output port's capabilities a little bit better. These signals seem to be called CEC, UTIL and HPD in some pinout I found online. HPD has a 1K pullup - some computers won't enable the I2C bus without the HPD signal being present.

5V on these video ports isn't specced to provided unlimited current, and is typically current-limited with a fuse inside your PC. This adapter doesn't have any meaningful current-limiting and any protection of power/data lines this adapter provides is mostly accidental - it is up to you to not abuse your computer's ports. The tools I provide are designed to give you capabilities over safety, as a rule. If you connect a typical 5V/3.3V device breakout to this port, you should be safe. I use this breakout personally and haven't experienced any problems.

I don't guarantee that this adapter will work with any kind of conversion adapters, such as DisplayPort or VGA ones - as much as I would love to guarantee that, I have no control over that.

I use this on Linux and I recommend you do, too. Last time I did research, Windows didn't expose I2C interfaces to users - there are some proprietary utilities for that, but I have no idea if they'd work for your usecase and I don't endorse their use in any way, given that I2C on Linux is one sudo modprobe i2c-dev away. I don't think that a virtual machine will work, either. I have no idea whether MacOS would work for this.