I have bought the QTR-HD-09A sensor for my line following robot. I want to ask about whether it’s coding is similar to the code of the QTR-8A and if I got get a sample code for QTR-HD-09A, it would be amazing. and what are the major difference between the QTR-HD-09A and QTR-8A.

In addition, I would like to ask whether the QTR-8RC sensor accepts the function readWhiteline() or not, or is it only applicable to QTR-8A.


In practice, the major difference between those two QTR reflectance arrays is the spacing between each sensor. The QTR-HD-09A sensor also has more emitter control options, which are discussed under the “Emitter control” heading of its product page.

Aside from the emitter control, interfacing with the sensors is the same (an analog voltage output for each sensor reading), and our Arduino library for our QTR reflectance sensors works with both of them. The QTRAExample.ino example from the library will work for both sensors with the adjustments/considerations described in the comments.

The readLineWhite() command from that library works with both A-type and RC-type QTR sensors.