A miniature mechanical driver 10 comprising a shape memory alloy 103 coupled to a wedge shaped element 102 in constant contact with a piston 101, such that the shape memory alloy is able to displace the wedge shaped element resulting in deflection of the piston. The wedge shaped element may have one or two sloped sides and have planar surfaces at either side of the sloped side. Preferably the wedge shaped element is attached to a frame by flexible tethers and the shape memory alloy is a wire that is looped around part of the wedge element. There may be a return springs 104 coupled to the wedge element and the piston. Preferably driver is used in a pump and an infusion system. An embodiment comprising a lever between the wedge shaped element and the piston is also claimed.
