Problems with QTR-1RC

Forum 2005-2010 (read only) Hardware Interfacing
#1

Hello, I have a big problem.
I have bought a QTR-1RC to see how to read data with it on a Arduino Duemilanove ATmega328.
My setup is:
QTR-1RC Vin connected to 5V
QTR-1RC GND connected to Arduino GND
QTR-1RC OUT connected to Arduino digital pin 3

The sketch that I used I found in Pololu examples with a few modifications to the entry pins and variables.

#define NUM_SENSORS 1 // number of sensors used
#define TIMEOUT 2500 // waits for 2500 us for sensor outputs to go low
#define EMITTER_PIN 2 // emitter is controlled by digital pin 2

// sensors 0 through 7 are connected to digital pins 3 through 10, respectively
PololuQTRSensorsRC qtrrc((unsigned char) {3},
NUM_SENSORS, TIMEOUT, EMITTER_PIN);

The rest is exactly like the pololu sketch.

#2

I have a big problem.

But you don't say what this problem is!

What are you seeing and what do you expect to see?

#3

Sorry!

It doesn't work. On the serial monitor in arduino it shows that it reads only 0. That would mean that the line is present on all the sensors. I think that moving my hand in fort of the sensor would give it different readings. But it doesn't.

I also tried reading with raw data. (qtrrc.read(SensorValues))

If you know what is wrong please help. Thank You!

#4

What you need to do is to post the actual code you have (using the # button). A reading of 0 implies that the light is not being blocked. Try blocking it with a bit of tape or card and see if you can read a 1. Try covering the sensor completely, it might be being swamped with ambient light.

Also you said:-

QTR-1RC Vin connected to 5V

and then

define EMITTER_PIN 2 // emitter is controlled by digital pin 2

These two are not consistent. Connect QTR-1RC Vin to PIn2 to be consistant.

#5

Thank You! It works now.

#6