A robot arm assembly for detecting a pose and force associated with an object is provided. The robot arm assembly includes an end effector having a plurality of fingers, and a deformable sensor provided on each finger. The deformable sensor includes a housing, a deformable membrane coupled to the housing, an enclosure filled with a medium, and an internal sensor disposed within the housing having a field of view directed through the medium and toward an internal surface of the deformable membrane. A processor is configured to receive an output from each internal sensor, the output including a contact region of the deformable membrane as a result of contact with the object. The processor determines an amount of displacement of the contact region based on the output from each internal sensor, and determines the pose and the force associated with the object based on the amount of displacement.