An accelerometer device (100) comprises a former (118) and an optical fiber (120) wound around the former. The winding of optical fiber (120) has a sensing portion (126) that is free to move in relation to a direction of desired sensitivity (128). A movable element (106) is disposed opposite the sensing portion (126) of the optical fiber (120), the movable element (106) being translatable so as to urge against the sensing portion (126) of the optical fiber (120) from a position external to the winding of the optical fiber (120) in order to vary a length of the optical fiber (120). The variation in the length of the optical fiber (120) caused by the moveable element (106) is indicative of an acceleration in the direction of desired sensitivity (128).