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. ** sold as a two pack **
In stock in Australia
Shipping from $2.90
+559 more from our supplier in 7-10 days
Our Code: SEN-10061
Supplier Link: [Pololu MPN:2458]
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.
There are several ways you can interface with the QTR-1A output:
The Pololu AVR library provides functions that make it easy to use these sensors with our Orangutan robot controllers and other AVR-based controller boards such as Arduinos.
This module has a single mounting hole intended for a #2 screw (not included); if this mounting hole is not needed, this portion of the PCB can be ground off to make the unit even smaller. The reflectance sensor ships with a 3-pin 0.1" header strip, which can be soldered in the conventional perpendicular orientation or parallel to the PCB, as shown below. You can also solder wires, such as ribbon cable, directly to the pads for the smallest installation.
Information about using the Pololu QTR-xA and QTR-xRC reflectance sensors, including sample oscilloscope screen captures of sensor outputs.
Information about installing and using the C/C++ libraries provided for use with Pololu products.
This guide explains how to use the QTRSensors library to read Pololu QTR sensors and QTR sensor arrays with Arduinos and Arduino-compatible devices like the Pololu Orangutan robot controllers.
A reference to commands provided in the Pololu C/C++ and Arduino libraries for the AVR.
Step-by-step instructions for building your own line-following courses.