Abstract: An angular positional sensor comprises a housing in which is mounted a rotary sensing device including a shaft which mounts a pendulum having relatively low inertia and a balanced member having relatively high inertia and rotatably mounted within the housing adjacent the pendulum member. At least the part of the housing containing the pendulum and the balanced member also contains a liquid to provide a viscous coupling between the pendulum and the balanced member. The arrangement is such, that in use, angular movement of the housing about the longitudinal axis of the shaft causes movement of the rotary sensing device relative to the shaft which is retained stationary by the pendulum which in turn is damped by the balanced member, to produce a signal representative of such angular movement from the rotary sensing device.