Abstract: A casing holds a syringe that contains a medicine, such as insulin, which may be driven out of the syringe by a plunger into a catheter attached to a human body. The power for the plunger drive mechanism is provided by a spiral spring mounted in the casing. A clockwork movement, regulated by a step electrical motor, controls the speed of the drive mechanism. A microprocessor controls the speed of the step electrical motor which regulates the clockwork movement. All of the components are contained in a casing which has an opening to allow the position of the plunger in the syringe to be seen from outside the casing.