A spring mattress including a plurality of interconnected coil-spring elements, said coil-spring elements being interconnected by securing elements, preferably in the form of spirals, which, at least in one plane essentially in parallel with the plane of the mattress, extend between and are attached to pairs of neighboring spring elements, thus interconnecting these spring elements. A circuit chip, laminated with the sensor chip, has a circuit formed on a surface thereof to detect the angular velocity based on a signal obtained from the sensor chip. The wavelength of the output optical signal can be the same as or different from one of the optical channels which comprises the WDM input signal. Preferably, said bearing block also supports an endless transmission screw on which are engaged a couple of transmission wheels coaxial with the driving rollers which they drive into rotation.