Method

A method of controlling a flow control device (100). The device includes a fluid path (104), a movable element (101), and a shape memory alloy (SMA) wire (103) for moving the movable element (101) in one direction or sense so as to cause the resistance of the fluid path (104) to increase or decrease. The device (100) is configured such that the movable element (101) does not move when no energy is supplied to the device (100). The method involves directing radiation (106) at an area of the device (100) so as to preferentially heat a portion of the SMA wire (103) and hence cause the portion of the SMA wire (103) to contract by a relatively large amount while another portion of the SMA wire (103) does not contract or contracts by a relatively small amount, wherein the radiation (106) is controlled so as to control the size of the portion of the SMA wire (103) that is preferentially heated and hence the resistance of the fluid path (104).