Pololu QTR-8RC Reflectance Sensor Array

PololuSKU: RB-Pol-52
Manufacturer #: 961

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Sale price £9.55

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In stock, 4 units

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  • Infrared phototransistor based reflectance sensor array
  • 3.3V to 5V operation
  • Measures only 2.95" x 0.5" x 0.125" and weighs 3.09 grams

The Pololu QTR-8RC Reflectance Sensor Array has 8 IR LED/phototransistor pairs mounted on a 0.375" pitch, making it a great detector for a line-following robot. Pairs of LEDs are arranged in series to halve current consumption, and a MOSFET allows the LEDs to be turned off for additional sensing or power-savings options. Each sensor provides a separate digital I/O-measurable output. The QTR-8RC reflectance sensor array is intended as a line sensor, but it can be used as a general-purpose proximity or reflectance sensor.

The outputs are all independent, but the LEDs are arranged in pairs to halve current consumption. The LEDs are controlled by a MOSFET with a gate normally pulled high, allowing the LEDs to be turned off by setting the MOSFET gate to a low voltage. Turning the LEDs off might be advantageous for limiting power consumption when the sensors are not in use or for varying the effective brightness of the LEDs through PWM control.

The LED current-limiting resistors for 5V operation are arranged in two stages; this allows a simple bypass of one stage to enable operation at 3.3V. The LED current is approximately 20-25 mA, making the total board consumption just under 100 mA.

Breaking the Module in Two:
If you don't need or cannot fit all eight sensors, you can break off two sensors and still use all 8 sensors as two separate modules, as shown in image. The PCB can be scored from both sides along the perforation and then bent until it snaps apart. Each of the two resulting pieces will function as an independent line sensor.

  • This module ships with a 25-pin 0.1" header strip and a 100 Ohm through-hole resistor as shown above.
  • Dimensions: 2.95" x 0.5" x 0.125" (without header pins installed)
  • Operating voltage: 3.3-5.0 V
  • Supply current: 100 mA
  • Output format: digital I/O compatible
  • Optimal sensing distance: 0.125" (3 mm)
  • Maximum recommended sensing distance: 0.25" (6 mm)
  • Weight without header pins: 0.11 oz (3.09 g)

Customer Reviews

Based on 4 reviews
Nice Product

Nice product. Small design and a perfect reflectance sensor array.

Nice product

More efficient. Small design and easy to use.

works very well with Odroid C1

No need to have Arduino board to connect this sensor. One can drive it directly from Odroid C1, using wiringPi Lib.

Line Tracking Sensor

Used it for a line tracking robot. it is very accurate to be used on any 2 surfaces that you like. in my case it was a black line over a gray concrete surface.

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