A need has been recognised for equipment that can be used to provide objective evaluation of exercise of the upper limb in occupational therapy while being motivational to the patient. The microcomputer was seen to be a suitable tool as part of a system that might satisfy this need. After consulting experienced hand therapists the criteria were established for equipment that would encourage and quantify exercise. Three systems were built that represented three methods of resistive exercise. These were presented to therapists in a structured assessment to determine the most suitable. As a result of this a system employing a dashpot and a potentiometer connected to a BBC microcomputer was designed. Software was written in the form of activities that could be controlled by the movements of exercise on the equipment. Dashpot resistance could be varied and graded and the range of software was of varied motivational content. This allowed the principal movements of the wrist and forearm to be objectively exercised. After suitably calibrating the system it was used to assess patient effort and ability, and hence progress of treatment.