Encoder Class

The encoder class is used to program the wheel encoders. It uses infrared light transmission to determine the speed at which the wheel is turning. By having a known number of slots in the wheel, the distance which a wheel turns can be easially calculated as the beam of light is continuously interrupted, sending a high or low signal back to the microcontroller. This information when combined with the time it takes to shift from a high to a low signal is used to calculate the speed at which the wheel is turning.

.cpp Code

#include "encoder.h"

 encoder :: encoder (unsigned int slots, unsigned int diameter, unsigned int pin){
	m_speed = 0.0;
	m_currentTime = 0.0;
	m_slots = slots; //number of slots in the encoder wheel is 20, but can be changed
	m_diameter = diameter; //diameter of the wheel
	m_pin = pin;
}

void encoder::updateTime(unsigned int time){
	m_currentTime = time; //storing the time
	m_speed = (62500*(207.35/(360*(18/m_currentTime))))/1000; //calculation to find speed
}

double encoder::getSpeed(){
	return(m_speed); //gets the speed from updateTime
}

void encoder::zeroSpeed(){
	m_speed = 0.0; //not moving, set to zero
}

.h Code

#ifndef encoder_h
#define encoder_h

class encoder{

private:
	double m_speed; //float to allow the more accuracy for speed
	double m_currentTime;
	unsigned int m_slots;
	unsigned int m_diameter;
	unsigned int m_pin;
	double m_prescalar;

public:
	encoder(unsigned int slots, unsigned int diameter, unsigned int pin);
	//Encoder is the constructor that sets/initializes the parameters
	void updateTime(unsigned int time); //function to update the current time from the internal
	timer
	double getSpeed(); //calculate the speed
	void zeroSpeed(); //set the speed to zero
};

#endif