SparkFun Line Sensor Breakout - QRE1113 (Digital)

The SparkFun Line Sensor Breakout - QRE1113 (Digital) is a compact and versatile device that features a digital output. It uses a capacitor discharge circuit to measure the amount of reflection. This sensor is ideal for line sensing applications where only digital I/O is available. It is compatible with both 3.3V and 5V systems.

The QRE1113 IR reflectance sensor on the board consists of two components - an IR emitting LED and an IR sensitive phototransistor. When power is applied to the VCC and GND pins, the IR LED within the sensor lights up. A 100Ω resistor is included on the board and is placed in series with the LED to limit current. The phototransistor's output is connected to a 10nF capacitor. The quicker this capacitor discharges, the more reflective the surface is.

These sensors are commonly used in line-following robots. Since white surfaces reflect more light than black ones, the capacitor will discharge more quickly when directed at a white surface than at a black one. This makes it possible to differentiate between different surface colors and patterns.

The power input and output pins are conveniently brought out to a 3-pin, 2.54mm pitch header. For easy attachment, the board includes a single mounting hole. A compact size of 7.62mm x 13.97mm makes it easy to integrate into various projects.

SparkFun also offers an analog version of this board for applications that require analog I/O.

Key Features:

• Operates at 5VDC
• Requires a supply current of 25mA
• Compatible with digital I/O
• No need for an ADC
• Optimal sensing distance of 3mm

Relevant Documents:

• Schematic
• Eagle Files
• Datasheet (QRE1113)
• GitHub