| Bend Sensor® LED Display Demo: This simple Bend Sensor® LED display demo uses a display driver to translate an analog input into ten separate voltage levels. As each level is attained, current is drawn through an LED, lighting it. Consecutive LEDs in a bank are lit as the input voltage goes from high to low. The LM3915 is a logarithmic display driver. Since the voltage divider response curve, and therefore the input, is roughly logarithmic, a logarithmic driver better follows the response. The input consists ofthe Bend Sensor® device in a simple voltage dividerwith RM. The resistor RM is chosen to maximize the use ofthe Bend Sensor® device dynamics. Replacing RM with a resistor in series with a pot will allow the user to adjust the sensitivity range of the Bend Sensor® device. As the pot is adjusted to a low value, the high deflection dynamics ofthe Bend Sensor® device will be displayed. When the pot is adjusted to a high value, the low deflection dynamics will be displayed. The display driver has an internal unity gain buffer at the input that isolates the Bend Sensor® device and minimizes bias current errors. In the configuration shown, a 9 volt battery is used as the voltage source. The top of the driver's ladder is about 7.2 volts (3 diode drops below V+), * while the bottom is at about 0.6 V (1 diode drop above ground). The input ranges from 7.8 volf^^ JF |