This QRE1113 breakout board features a digital output, using a capacitor discharge circuit to measure the amount of reflection. This tiny board is perfect for line sensing when only digital I/O is available.
The board's QRE1113 IR reflectance sensor is comprised of two parts: an IR-emitting LED and an IR-sensitive phototransistor. When you apply power to the VCC and GND pins, the IR LED inside the sensor will illuminate. A 100Ω resistor is on board and placed in series with the LED to limit current. The output of the phototransistor is tied to a 10nF capacitor. The more reflective the surface is, the faster that capacitor discharges.
These sensors are used widely in line-following robots. White surfaces reflect much more light than black, so, when directed toward a white surface, the capacitor will discharge faster than it would when pointed toward a black surface.
The power input and analog output pins are brought out to a 3-pin, 0.1"-pitch header. The board also has a single mounting hole.
The board measures 0.30 × 0.55 inches (7.62 × 13.97 mm).
There also is a simple analog-output version of this board.
IR Sensor Board Features
- 5V DC operating voltage
- 25mA supply current
- Digital I/O compatible
- No ADC required
- Optimal sensing distance: 0.125" (3mm)
IR Sensor Board Resources
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