CAR_Timer Library Documentation

Overview

The CAR_Timer library simplifies working with the millis() function on Arduino. It provides a convenient way to measure elapsed time and manage timers.

Installation

To use the CAR_Timer library, include it in your project by copying the CAR_Timer.h file into your project's directory and include the header file in your sketch.

#include "CAR_Timer.h"

Class: CAR_Timer

Constructors

CAR_Timer()

Initializes the timer with the current time from millis().

CAR_Timer timer;

CAR_Timer(unsigned long val)

Initializes the timer with the current time from millis() minus the specified value.

CAR_Timer timer(1000); // Timer initialized 1000 ms ago

CAR_Timer(const CAR_Timer &orig)

Copy constructor that initializes the timer with the value from another CAR_Timer object.

CAR_Timer timer1;
CAR_Timer timer2(timer1); // Copy constructor

Operators

operator unsigned long() const

Returns the elapsed time in milliseconds since the timer was initialized.

unsigned long elapsed = timer;

CAR_Timer& operator=(const CAR_Timer &rhs)

Assigns the value from another CAR_Timer object to this timer.

CAR_Timer timer1;
CAR_Timer timer2;
timer2 = timer1;

CAR_Timer& operator=(unsigned long val)

Sets the timer to the current time minus the specified value.

timer = 500; // Timer set to 500 ms ago

CAR_Timer& operator-=(unsigned long val)

Subtracts the specified value from the timer.

timer -= 100; // Timer subtracted by 100 ms

CAR_Timer& operator+=(unsigned long val)

Adds the specified value to the timer.

timer += 100; // Timer added by 100 ms

template<typename T> CAR_Timer operator-(T val) const

Returns a new CAR_Timer object with the specified value subtracted.

CAR_Timer newTimer = timer - 100;

template<typename T> CAR_Timer operator+(T val) const

Returns a new CAR_Timer object with the specified value added.

CAR_Timer newTimer = timer + 100;

Usage Examples

Example 1: Basic Timer Usage

This example demonstrates how to use the CAR_Timer class to measure elapsed time and perform an action every second.

#include <CAR_Timer.h>

CAR_Timer timer;

void setup() {
    Serial.begin(9600);
}

void loop() {
    if (timer >= 1000) { // Check if 1000 ms (1 second) has passed
        Serial.println("One second has passed");
        timer = 0; // Reset the timer
    }
}

Example 2: Timer with Initial Value

This example initializes the timer with an initial value of 1000 ms and checks the elapsed time.

#include <CAR_Timer.h>

CAR_Timer timer(1000); // Timer initialized 1000 ms ago

void setup() {
    Serial.begin(9600);
}

void loop() {
    if (timer >= 2000) { // Check if 2000 ms (2 seconds) has passed since initialization
        Serial.println("Two seconds have passed since initialization");
        timer = 0; // Reset the timer
    }
}

Example 3: Using Copy Constructor

This example demonstrates the use of the copy constructor to create a new CAR_Timer object from an existing one.

#include <CAR_Timer.h>

CAR_Timer timer1;

void setup() {
    Serial.begin(9600);
    timer1 = 500; // Initialize timer1 with 500 ms
    CAR_Timer timer2(timer1); // Copy constructor
}

void loop() {
    if (timer1 >= 1000) {
        Serial.println("Timer1: One second has passed");
        timer1 = 0;
    }

    if (timer2 >= 1000) {
        Serial.println("Timer2: One second has passed");
        timer2 = 0;
    }
}

Example 4: Assignment Operator

This example demonstrates the use of the assignment operator to set the value of one CAR_Timer object to another.

#include <CAR_Timer.h>

CAR_Timer timer1;
CAR_Timer timer2;

void setup() {
    Serial.begin(9600);
    timer1 = 500; // Initialize timer1 with 500 ms
    timer2 = timer1; // Assignment operator
}

void loop() {
    if (timer1 >= 1000) {
        Serial.println("Timer1: One second has passed");
        timer1 = 0;
    }

    if (timer2 >= 1000) {
        Serial.println("Timer2: One second has passed");
        timer2 = 0;
    }
}

Example 5: Timer Arithmetic

This example demonstrates how to use the arithmetic operators to create a new timer object with an adjusted value.

#include <CAR_Timer.h>

CAR_Timer timer;

void setup() {
    Serial.begin(9600);
    timer = 500; // Initialize timer with 500 ms
}

void loop() {
    CAR_Timer newTimer = timer + 500; // New timer 500 ms ahead
    if (newTimer >= 1000) {
        Serial.println("NewTimer: One second has passed");
        newTimer = 0;
    }

    if (timer >= 1000) {
        Serial.println("Timer: One second has passed");
        timer = 0;
    }
}