Arduino Library for QTR Reflectance Sensors

Table Of Contents

1. Introduction

QTR-1RC reflectance sensor.

QTR-8A reflectance sensor array.

The Pololu QTR reflectance sensors carry infrared LED and phototransistor pairs that can provide analog measurements

of IR reflectance, which makes them great for close-proximity edge detection and line-following applications. The

modules come as compact, single-sensor units (QTR-1A [http://www.pololu.com/catalog/product/958] and

QTR-1RC [http://www.pololu.com/catalog/product/959]) or as 8-sensor arrays (QTR-8A [http://www.pololu.com/catalog/product/960]

and QTR-8RC [http://www.pololu.com/catalog/product/961]) that can be optionally split into a 2-sensor array and a 6-sensor

array.

The modules are available in two different output formats: the QTR-xA outputs an analog voltage between 0 and Vcc that

can be measured by an analog-to-digital converter (ADC), and the QTR-xRC outputs a pulse that can be measured by a

digital I/O line (the duration of which provides an analog measurement of reflectance).

QTR-1A reflectance sensor schematic diagram. QTR-1RC reflectance sensor schematic diagram.

Please see the product pages [http://www.pololu.com/catalog/category/7] for more information on how these sensors work.

This document will explain how to install Arduino libraries for the Pololu QTR reflectance sensors, and it will provide

sample sketches as well as links to library documentation. The libraries will give you everything you need to interface

with a QTR-8x reflectance sensor array or multiple QTR-1x reflectance sensors, including advanced features like

automatic calibration and, in the case of line detection, calculation of the line’s position.

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