Abstract: A signature verification tablet comprises two piezo-electric membranes each having a plurality of line electrodes on one side. The membranes are sandwiched together, with the line electrodes on one membrane at right angles to the line electrodes on the other. The line electrodes on each membrane are connected together in three interleaved sets, so that when a signature is written on the tablet, a series of pulses is produced containing direction and speed of movement information from which the authenticity of the signature can be verified.