Abstract: A speed sensing device comprises two electronic counters fed with electric pulses from first and second sensors; the first sensor emits sensing pulses at a rate proportional to the speed of a member past said sensor, and the second sensor emits reference pulses at a rate proportional to that of a reference member past the second sensor. Each of the counters is adapted to emit an output signal whenever a respective preselected number of pulses has been received since the counter was last reset, and both said counters are arranged to be reset whenever either counter emits an output signal.Such a device may be used in association with a web-consuming machine receiving web from a bobbin. The first and second sensors are then arranged respectively to sense the rotational speeds of the bobbin and of a reference member in the machine drive e.g. a drive shaft. As web is removed from the bobbin, its rotational speed increases (relative to the machine speed) due to the decreasing diameter of the bobbin.