Using Wheel Encoders

Support Other Pololu products
1

Hi there,

Would it be possible for someone to help a newbie out please?

I’m building an obstacle avoiding robot and I’ve connected two pololu wheel encoders ( one for each micro metal gearmotor + the pololu wheels) up to my arduino uno using the code below:

#include <PololuWheelEncoders.h>

PololuWheelEncoders encoders;

void setup() { 

  encoders.init(2,12,3,13);
  
  Serial.begin(19200);
  delay(1000);
  Serial.print("Start");
  Serial.println();
}
void loop()
    {
      Serial.print(encoders.getCountsM1());
      Serial.print(" ");
      Serial.print(encoders.getCountsM2());
      Serial.print(" ");
      Serial.println();
      
    }

I’m getting 0’s and 1’s or -1’s as an output in my serial monitor when I manually turn the motors and I’m not sure how to use this information to calculate distance. Should I be getting an incremental output? How can I tell how many times the wheels have rotated?

I know this stuff may be pretty basic but I’ve done quite a thorough search and have just ended up more confused.

Any help will be appreciated!

2

Hello.

The behavior you are seeing makes me suspect that something is connected incorrectly. Can you tell me how you have everything connected? A picture of your setup would be very helpful.

- Grant

3

Hi Grant,

Thank you for your reply.

I’ve just this minute discovered that I had made a bit of a schoolboy error. I’m using the Sparkfun Xbee shield and I forgot to move the switch from DLINE to UART before reading from the serial monitor! :blush:

The serial readings are now incrementing as I would have expected.

Sorry about that, although hopefully this will serve as a reminder for anyone else who does a search with a similar problem :slight_smile:

Thanks again,

Lee