Reflectance sensorQTR-L-1A - analog (2 pcs) - Pololu 2454

Product description: Reflective sensor QTR-L-1A  - analog (2 pcs)

The sensor consists of IR LED and receiver in the form of phototransistor. In addition to these two basic elements, in the circuit are: resistor limiting the transmitting LED's current 220 Ω and the pulling-up resistor, output of the phototransistor collector for supply voltage with the value of 20kΩ. The output is an analog voltage that depends on the color of the surface. The array below presents other examples of values depending on the distance and color of the surface.

 

Distance White surface Black insulating tape 6 mm 0.2 V 3.8 V 25 mm 2.4 V 3.5 V

  

The product is compatible with Arduino

The manufacturer has prepared a library that simplifies maintenance of the sensor for Arduino users.

Method of using

• Connection of the sensor's output to the analog-to-digital transmitter (for example, embedded in the microcontroller).
• Connection usingthe comparatordirectly to the I/O pins.

• Using the built-in, in some microcontrollers, internal comparator.

Daylight, especially sunlight can affect the operation of the sensor. In the case when the output voltage is too low, you should install a rim that protects the sensor from the exposure to external light.

 

Pinout of reflective sensor

The sensor has three simple pins: power supply - VDD (supply voltage), ground - GND and the analog output signal OUT. For proper operation, it is sufficient to connect the power supply.

Specification of QTR-L-1A reflective sensor

• The supply voltage: 5 V
• The average current consumption: 17 mA
• Recommended measuring range: 3 mm - 6 mm
• Maximum measuring range: 25 mm
• Output: voltage-analog signal (0 V up to the value of the supply voltage)
• Dimensions : 7.6 x 8.9 x 3.1 mm (without connectors)
• Weight: 0.2 g (without connectors)

  Useful links

• The manufacturer's website
• Details of operation of the sensor
• AVR library from the Pololu
• Library for Arduino