Murata pattern recognition sensors for compact banknote readers have excellent gap characteristics
Hoofddorp, Netherlands: Murata has released four new products in its BS05 series of magnetic pattern recognition sensors. The BS05M1HFAL, BS05M1KFCA, BS05M1KFFA and BS05M1KFBB magneto-resistive sensors are designed for ATMs, banknote counters, detectors and other validator applications. The devices are suitable for detection of magnetic thread or magnetic ink, and enable simple and quick mounting. These parts retain around 70% of their output voltage at a 0.1mm gap between sensor and substrate, compared to just 4% for typical coil head sensors. Along with their stable frequency characteristic, which is independent of the scanning speed, this makes them suitable for high-speed processing devices that demand superior accuracy.
Magneto-resistive sensors consist of a permanent magnet and two sensing elements to ensure compensation for changes in temperature. When a magnetic material is passed over the sensor, the elements detect a change in the magnetic flux density, which is converted into an electrical signal. In banknote validation applications, the sensor is typically mounted beneath a pressure roller which helps keep the banknote in contact with the sensor’s surface. In Murata’s multi-channel devices, multiple sensors are be mounted next to each other, to allow magnetic pattern recognition over the whole width of the banknote.
The BS05M1HFAL is an 8-channel sensor with channel width of 3mm, while the BS05M1KFFA has thirteen channels, each 10mm wide. Both have all their channels mounted in a straight line. This layout is especially useful in banknote validators that use a pressure roller, as the centre of the roller can be directly above the line of sensing elements, leading to lower signal loss and eliminating time differences between signals. The in-line layout also eases handling and PCB assembly and reduces the size of the pressure roller and sensing assembly.
The BS05M1KFCA six-channel and BS05M1KFBB 13-channel sensors have 10mm channel widths with channels offset in alternate directions to make a zig-zag style configuration. This ensures there is no physical gap between each channel, leading to very reliable detection of banknotes. These sensors are therefore targeted at high end machines that have high scanning speed and require high detection reliability.