Wheel Encoders for DFRobot 3PA and 4WD Rovers (SKU:SEN0038)

From Robot Wiki

Introduction

This encoders are designed for DFRobot 3PA and AWD Rovers. It can give you the rotation degree of the wheels. Encoder uses non-contact method to convert the angular displacement signals. Best fit with Micro DC Geared Motor.
It includes encoders, plastic tube, paper-mediated gasket etc.

Specification

Voltage:+5V
Current:<20mA
Resolution:20 PPR
Weight:20g

Sample Code

// # 
// # Editor     : Lauren from DFRobot
// # Date       : 17.01.2012

// # Product name: Wheel Encoders for DFRobot 3PA and 4WD Rovers
// # Product SKU : SEN0038

// # Description:
// # The sketch for using the encoder on the DFRobot Mobile platform

// # Connection:
// #        left wheel encoder  -> Digital pin 2
// #        right wheel encoder -> Digital pin 3
// #


#define LEFT 0
#define RIGHT 1

long coder[2] = {
  0,0};
int lastSpeed[2] = {
  0,0};  


void setup(){
  
  Serial.begin(9600);                            //init the Serial port to print the data
  attachInterrupt(LEFT, LwheelSpeed, CHANGE);    //init the interrupt mode for the digital pin 2
  attachInterrupt(RIGHT, RwheelSpeed, CHANGE);   //init the interrupt mode for the digital pin 3
  
}

void loop(){
  
  static unsigned long timer = 0;                //print manager timer
  
  if(millis() - timer > 100){                   
    Serial.print("Coder value: ");
    Serial.print(coder[LEFT]);
    Serial.print("[Left Wheel] ");
    Serial.print(coder[RIGHT]);
    Serial.println("[Right Wheel]");
    
    lastSpeed[LEFT] = coder[LEFT];   //record the latest speed value
    lastSpeed[RIGHT] = coder[RIGHT];
    coder[LEFT] = 0;                 //clear the data buffer
    coder[RIGHT] = 0;
    timer = millis();
  }
  
}


void LwheelSpeed()
{
  coder[LEFT] ++;  //count the left wheel encoder interrupts
}


void RwheelSpeed()
{
  coder[RIGHT] ++; //count the right wheel encoder interrupts
}