Introduction: Non-blocking Virtual Delay Library for the Arduino

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Introduction

The standard Arduino delay() function blocks the Arduino, that is not always allowed. The standard delay has limitations too; it is not possible to use multiple delays at the same time. So I decided to developed a VirtualDelay library which has many advantages:

Step 1: Advantages of the VirtualDelay Library

  • The delay is virtual, during the delay, the code execution is continued
  • We can use multiple delays sequentially in a loop.
  • We can use multiple delays simultaneously and independent of each other.
  • The delay time can set in micro-seconds or milli-seconds.
  • No hardware timers are used

There is another article HERE.

Step 2: Video

Step 3: Virtual Delay Library Files

You can download the library from GitHub.

Step 4: Simple Blinking LED Sketch With the VirtualDelay Library

#include <arduino.h><br>#include "avdweb_VirtualDelay.h"
#include <streaming.h></streaming.h></arduino.h>
const byte ledPin = 13;
bool b;
int i;
VirtualDelay singleDelay; // default = millis
void setup() 
{ pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}
void loop() 
{ singleDelay.start(400); // calls while running are ignored
  if(singleDelay.elapsed()) digitalWrite(ledPin, b=!b); // blink the onboard LED
  Serial << endl << i++; 
}

Step 5: Using 3 VirtualDelays in Sequence

Here we need three separate VirtualDelay instances: delay1, delay2 and delay3. The line with the macro DO_ONCE ensures that the sequence is started. You may use any instance e.g. delay2.start(0).

#include <arduino.h><br>#include "avdweb_VirtualDelay.h"
#include <streaming.h></streaming.h></arduino.h>
const byte ledPin = 13;
bool b;
int i;
VirtualDelay singleDelay; // default = millis
void setup() 
{ pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}
void loop() 
{ singleDelay.start(400); // calls while running are ignored
  if(singleDelay.elapsed()) digitalWrite(ledPin, b=!b); 
  Serial << endl << i++; 
}

This is the serial output:

delay1 200ms 200
delay2 100ms 300
delay3 400ms 700
delay1 200ms 900
delay2 100ms 1000
delay3 400ms 1400
delay1 200ms 1600

Step 6: One-shot Example

To create a one-shot, start() may only be called once during the loop, to do so, the macro DO_ONCE is used.

#include 
#include #include "avdweb_VirtualDelay.h"
VirtualDelay delay1;
void setup() 
{ Serial.begin(9600);
  Serial << "\ntestOneShot 2s\n"; 
}
void loop() 
{ DO_ONCE(delay1.start(2000)) // do only one time in the loop   
  if(delay1.elapsed()) Serial << millis() << "ms" ; 
}

Step 7:

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