A robotic arm as a simple sample changer for a diffractometer with very low component costs

Inexpensive model robots are a viable option for automation of simple, repetitive tasks and can be solutions when space restriction and funding are issues, both factors that may eliminate more advanced robots from consideration. A simple-to-program, inexpensive robotic arm has been integrated in a sample changer for room-temperature experiments on a neutron powder diffractometer. In spite of the limited precision inherent in a model, servo-controlled robot, a very reproducible overall system can be made. Simple `tricks' such as incorporating self-centering mechanisms, e.g. mechanically self-centering designs and magnets, can produce central forces that eliminate the need for high precision from the robot arm.