A mechanical driver comprising a wedge shaped member operatively coupled to a shape memory alloy such that the shape memory alloy is able to displace the wedge shaped member in an essentially linear direction. The wedge shaped member is in constant contact with a lever arranged so that it can rotate about a fixed pivot point. A piston is arranged such that it is constant contact with the lever at a point between the pivot point of the lever and the contact point between the lever and the wedge shaped member. Return springs are provided to return the piston, lever and wedge shaped member to their respective start positions. Activation of the shape memory alloy displaces the wedge shaped member along its linear direction and this causes the lever to be deflected about its pivot point and the piston to be deflected in an essentially linear direction that is perpendicular to the linear direction of travel of the wedge shaped member.