Grooved bar-code pattern recognition system with magnetoresistive sensor

A magnetic bar-code pattern recognition system with a magnetoresistive sensor is proposed. The bar-code consists of a set of grooves on an iron plate, similar to an optical bar-code pattern. When a magnet passes above the grooves on an iron plate, the magnetic field produced by the magnet is bent by the grooves. The bar-code pattern of grooves can be reconstructed by detecting the bend using the magnetoresistive sensor. Computer simulation results on magnetic flux density distribution near the grooves are presented, and prototype recognition systems with a magnetoresistive sensor are described. It is shown that a two-groove bar-code configuration with different groove depths depending on groove width and a thin-film magnetoresistive sensor construction are useful in realizing high-resolution detection systems