An exciting research project from MIT shows that it’s possible to embed machine-readable labels on 3D-printed objects using nothing more than an FDM printer and IR-transparent filament. The method is being called infrared tags; by embedding something like a QR code or ArUco markers in the structure of an object, that label can be detected by a camera and interactive possibilities are opened up.
A simple proof of concept is a wireless router with its SSID embedded on the side of the device and the password embedded in a different code at the bottom to ensure physical access is required to get the password. Mundane objects can have metadata embedded in them or provide markers for augmented reality functionality, such as tracking the object in 3D.
How are the codes actually embedded? The process is simple with the right tools. The team used a special filament from vendor 3dk.berlin that appears almost opaque in the visible spectrum, but transmits about 45% in IR. The machine-readable label is embedded into the walls of a printed object, either through a combination of IR PLA and air gaps to represent the geometry of the code, or through a multi-material print using IR PLA and regular (non-IR) . transmitting) PLA. Both provide enough contrast for an infrared-sensitive camera to detect the label, although the multi-material version performs slightly better overall. Unfortunately, the average mobile phone camera alone is not sensitive enough to IR to passively read these embedded tags, so the research used readily available cameras without IR-blocking filters, such as the Raspberry Pi NoIR.
The PDF has deeper details of the implementation for those of you who want to know more, and you can see a demo of a few different apps in the video, embedded below. Determining the provenance of 3D printed objects is a topic of debate in the industry, and it’s not hard to see how technology like this could be used to covertly identify objects without compromising their appearance.