One variation of a method for controlling a robotic arm includes: moving the robotic arm through a trajectory; at a first time in which the robotic arm occupies a first position along the trajectory, measuring a first capacitance of a first sense circuit comprising a first electrode extending over a first arm segment of the robotic arm; at a second time in which the robotic arm occupies a second position along the trajectory, measuring a second capacitance of the first sense circuit; calculating a first rate of change in capacitance of the first sense circuit based on a difference between the first capacitance and the second capacitance; in response to the first rate of change in capacitance of the first sense circuit exceeding a threshold rate of change, issuing a proximity alarm; and reducing a speed of the robotic arm moving through the trajectory in response to the proximity alarm.