Rangefinder.h

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#pragma once
 
#include <Arduino.h>
 
class Rangefinder 
{
protected:
    volatile uint8_t state = 0;
 
    uint8_t echoPin = -1;
    uint8_t trigPin = -1;
 
    // for keeping track of ping intervals
    uint32_t lastPing = 0;     
 
    // we set the pingInterval to 10 ms, but it won't actually ping that fast
    // since it _only_ pings if the ECHO pin is low -- that is, it will ping
    // in 10 ms or when the last echo is done, whichever is _longer_ 
    uint32_t pingInterval = 10;    
 
    // for keeping track of echo duration
    volatile uint32_t pulseStart = 0;
    volatile uint32_t pulseEnd = 0;
 
    // holds the last recorded distance
    float distance = 99;
 
public:
    Rangefinder(uint8_t echo, uint8_t trig);
 
    // must call init() to set up pins and interrupts
    void init(void);
 
    // checks to see if it's time to emit a ping
    uint8_t checkPingTimer(void);
 
    // checks to see if an echo is complete
    uint16_t checkEcho(void);
 
    float getDistance(void);
 
    // ISR for the echo pin
    void ISR_echo(void);
};
 
// ISR for the echo
void ISR_Rangefinder(void);
 
// we declare as extern so we can refer to it in the ISR
extern Rangefinder rangefinder;