Setting up the Pololu QTR-8A Reflctnc Sensor Array

Forum 2005-2010 (read only) Hardware Interfacing
1

I have the Pololu QTR-6A(Analog) in this case, as i snapped the two optional sensors off the end and am using the 6 sensors. I just bought this thing yesterday and i've tried to throw some code together based on the pololu site's instructions, But my Serial reads all 0's every time.

I have the Vcc from the sensor board hooked up to my +5V on my Arduino Duemillanove, Ground to Ground, the LEDON from the sensor array is on Digital Pin 5, which i set to HIGH in my code. And the 6 Signal wires from the sensor board are hooked to my Analog pins 0 - 5 respectively on the Arduino.

Here's my code,

#include <PololuQTRSensors.h>

PololuQTRSensorsAnalog qtra((unsigned char[]) {0, 1, 2, 3, 4, 5}, 6);
void setup()
{
** digitalWrite(5, HIGH);**

** int i;**
** for (i=0; i<250; i++)**
** {**
** qtra.calibrate(); **
** delay(20);**
** }**
}
void loop()
{

unsigned int sensor[6];
int position = qtra.readLine(sensor);
digitalWrite(5, HIGH);
Serial.print(qtra.readLine(sensor));
**Serial.println(); **
delay(50);

}

Again, The problem is that my Serial reads all 0's, every time. :cry:

2

I'm having sort of the same problem. Trying to setup the same 6 sensors into an array. Haven't figured that one out yet. I am able to get a sensor reading to the serial port though.

I'll post later with the code I made for it.
At work now.

Sean.

3

Okay here is the code I'm using and I get the serial out and the numbers to the serial monitor in Arduino 16.
I borrowed it from the servo example in the playground and added the serial to see the numbers.

#include <Servo.h> 

Servo myservo;  // create servo object to control a servo 

int pos = 0;    // variable to store the servo position 

void setup() 
{ 
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object 
  Serial.begin(19200);
} 

void loop() 
{
  digitalWrite(10, HIGH);
  pos = analogRead(0);
  pos = map(pos, 0, 1023, 0, 180);  
  myservo.write(pos);              // tell servo to go to position in variable 'pos' 
  Serial.println(pos);
  delay(15);                       // waits 15ms for the servo to reach the position 
  }

Maybe that helps?

I can't get the PololuQTRSensors.h to work so I can calibrate them. Can you get this working? When I compile is says: "error 30 PololyQTRSensors.h: No such file or directory." I unzipped it to the library folder under hardware.

I just figured it out. I have to put the folder that contains the header file into the library folder and not in another folder that was containing the other things that came with it.

4

Okay I see your point, now that I got my folder problem fixed I am getting the same all zeros streaming down the left side for the calibration. I'm working on it too.

Sean.