QTR-1A Reflectance Sensor (coppia)

Description

The QTR-1A reflectance sensor carries a single infrared LED and phototransistor pair in an inexpensive, tiny 0.5" x 0.3" module that can be mounted almost anywhere and is great for edge detection and line following applications. The reflectance measurement is output as an analog voltage. Note: The QTR-1A reflectance sensor requires an analog input to take readings. The similar QTR-1RC reflectance sensor is available with a digital I/O-compatible output. The Pololu QTR-1A reflectance sensor carries a single infrared LED and phototransistor pair. The phototransistor is connected to a pull-up resistor to form a voltage divider that produces an analog voltage output between 0 V and VIN (which is typically 5 V) as a function of the reflected IR. Lower output voltage is an indication of greater reflection. The LED current-limiting resistor is set to deliver approximately 20-25 mA to the LED when VIN is 5 V. The current requirement can be met by some microcontroller I/O lines, allowing the sensor to be powered up and down through an I/O line to conserve power. Because of its small size, multiple units can easily be arranged to fit various applications such as line sensing and proximity/edge detection. For a line sensor with eight of these units arranged in a row, please see the QTR-8A reflectance sensor array . Specifications Dimensions: 0.3" x 0.5" x 0.1" (without header pins installed) Operating voltage: 5.0 V Supply current: 25 mA Output format: analog voltage Output voltage range: 0 to supplied voltage Optimal sensing distance: 0.125" (3 mm) Maximum recommended sensing distance: 0.25" (6 mm) Weight without header pins: 0.008 oz (0.23 g)