tl;dr: OpenArm is an open-source 7DOF humanoid arm targeting physical AI research in contact-rich environments, emphasizing backdrivability, compliance, and safe human-robot interaction. A complete bimanual system runs $6,500 USD, with hardware released under CERN-OHL-S-2.0 and software (ROS2, Isaac Lab, MuJoCo, teleop, datasets) under Apache-2.0. The project also provides "OpenArm Cell," a standardized environment for reproducible evaluation across research groups.