Abstract: A transducer for converting mechanical forces into corresponding electrical signals. In one embodiment, the transducer takes the form of a writing instrument for use in a user identification system whereby the time-varying force between the instrument and a writing surface generates a waveform which is characteristic of the individual doing the writing. The transducer includes first and second core members being interconnected by a resilient member with the core members being operatively coupled to a coil whose inductance varies in accordance with the forces generated during writing. The coil is operatively coupled to an oscillator whose frequency changes in accordance with the varying inductance to produce the waveform.

Abstract: The thermal printer system is comprised of a means for generating heated air and a means for controlling the application of the heated air to a thermally sensitive recording medium. In an embodyment of the invention there is provided a means for ionizing a column of gas and a means for attracting or repelling the ionized column of gas along a desired path in response to a control signal. Interposed along the desired path is a means for heating the gas and a thermally sensitive recording medium positioned to intercept the column of heated gas such that a record is made on the recording medium which record is a function of the control signal.