If you want a robot arm, either for some practical job or just fun, you have a lot of options. There are many consumer and industrial robot arms on the market, but the models that aren’t glorified toys tend to be pricey. You can also build your own. If you go that route, you’ll want a design that is well-engineered and well-documented. It isn’t free, but the ARCTOS is a high-quality option that meets both of those criteria.

Based on aesthetics alone, the ARCTOS looks fantastic. It resembles something you’d see in a lab in a sci-fi movie. But it also offers more than a pretty package. The robot arm has six degrees of freedom and a payload of 500 grams, making it suitable for tasks ranging from pick-and-place to packing boxes. Best of all, you can assemble it using easily sourced hardware and 3D-printed parts. Those parts are PLA and just about any modern 3D printer can handle the fabrication.

The ARCTOS design files will set you back €39.95 (about $44) and sourcing all of the parts for the build will cost around $400. Stepper motors actuate the joints, through simple belt drives and cycloidal gear boxes. An Arduino Mega 2560 controls those through a standard CNC shield. It runs open source firmware based on GRBL that will work with a variety of control software options to suit different tasks.