Allows you to define sensors that track whether a physical marker is visible to a camera.

What can you use this for? ArUco markers are commonly used for grand things like robot positioning, but I created this toolkit for a far more mundane reason: I wanted [Home Assistant][hass] to be able to detect whether my trash and recycling bins had been taken to the curb, and send me an alert if there is a pickup the next morning and the bin is still sitting next to the house.

Some other things it can be useful for:

• Have a camera in your garage? Paint a marker on the garage door to tell if it's open or closed. Paint a marker on the floor, if it's not detected then there is likely a car in the garage covering it up.
• Add markers to all your storage bins, and put a camera in your storage room. Easily determine which bins are in storage and which are somewhere else.
• The ultimate presence detection! Put cameras on the ceiling in every room, and tattoo a marker on top of your bald head! Hmm, maybe not that one.

An ArUco marker is a grid of black and white squares that is similar to a QR Code. But where a QR code can encode a string of arbitrary text, the only information in an AruCo marker is a single number.

These markers are designed to be easy to detect in an image, and with the right preparation they can provide enough information to allow you to determine their "pose" (the distance, orientation, and angle of the marker in relation to the camera that detected it).

AruCo markers come in a variety of families, but we only support a few. The supported families are: 4X4, 5X5, 6X6, and 7X7. The family determines the dimensions of the grid that encodes the number for the marker. The 4X4 family is a grid of 4 rows and 4 columns, and you can probably guess what that means about the other families.

Unless you have a compelling reason to switch I recommend sticking with 4X4 because the small number of squares in the grid makes it easy to detect from a distance, and it's simple enough that for many purposes you can even tape out the grid and paint the squares by hand.

FYI: "AruCo" stands for "Augmented Reality University of Cordoba".

pip install tag-sensor

Take a look at:

• Configuration Options
• Making Markers
• Contributing

Problems?

• Home Assistant Community Forum.
• /r/homeassistant subreddit.
• Open an issue on GitHub.

Created by Jason Kohles.

For a full list of all authors and contributors, check the contributor's page.