How to do multiple tasks in Arduino | Beginners | millis() function 

Same

If it helps, basically, instead of using a command that halts command execution (delay) he's simply comparing times in a conditional statement to control when the light turns on/off. Using delay, the loop() function takes 2 seconds to complete before it runs again in the initial code, because the delay there is 2 seconds. This leaves very little time for the Arduino to realize when a button press occurs in the latter part of the code. Without using delay, the loop runs at a much higher speed and thus condition checks run much faster. For example, let's assume this code is short enough that without delays, loop() running a single time only takes 100 milliseconds at 5:17. So in one second, loop() runs 10 times. So the loop would check for a button press every 10 milliseconds while also checking whether the current time is a minimum of 1000 milliseconds after the last time stamp we saved to the prevTime() variable. Since prevTime() is only set when the condition statement is true, it remains whatever value it was set to eg. 5000 until the difference between the previously saved time and the currently reported time (time continuously updates during program execution), is greater than 1000 ms. He probably should have set it to >=1000ms because technically, the LED would always be on for slightly longer than the intended 1 second otherwise.

If that is true then you haven't looked into ESP32 ESP32 Multitasking shits all over this and then some

@@martinkuliza I needed this for Arduino not esp32

@@ineffige OK, I guess. if you want to make life hard for yourself, go for it. I also know how to implement Multi Tasking (Not like in this video) but as you would in ESP32 using FreeRTOS as well I'm not suggesting you should do it, I'm just saying YOU CAN DO IT YOU CAN TRY IT YOU CAN INSIST ON MAKING YOUR LIFE DIFFICULT or you can transition to something that will make your life easier don't get me wrong I'm from 70s Electronics, i have Massive respect for Arduino but fact is fact, Arduino doesn't compare to ESP32 which is why Arduino Dev Boards are now being sold with Bluetooth and WiFi Integrated the issue with these boards is still Even though they have WiFi and Bluetooth They haven't increased in memory they don't have dual core processing Its sad to admit, But Arduino is Dying to persist through a problem using band aid solutions like milli's is to continue to make your life difficult for no reason but hey.... WHATEVER MAKES YOU HAPPY MATE

@@martinkuliza lol. If I wanted tips for esp32 I would search for it not Arduino. Why so bitter dude

@@ineffige Bitter ??? No. I'm not bitter I'm offering advice. LOL Where did you get bitter from ? No..... Not bitter, Just trying to make life easier for people. it's commonly understood that if you have a delay issue using delay() in Arduino you move to millis. AND THAT'S WHERE MOST PEOPLE GET STUCK Mainly because they don't know about ESP32 (Most people don't) it's nothing to be ashamed about I'VE PERSONALLY BEEN DOWN THIS ROAD. When i saw the video and the word MULTI TASKING i assumed he was going to talk about task creation in ESP32, Instead he went on about Arduino Multi Tasking in Arduino is a real pain staking process, Later down the track you realize, you should have gone with ESP32 so, I'm not bitter I'M GIVING YOU THE FORESIGHT OF MY EXPERIENCE I'm trying to help you, I"m not bitter OK, so tell me this then, if you're aware of ESP32, and Arduino's Memory and core limitations as well as increased price why do you continue to use it

yeah thats my problem i have a timer which runs perfectly but i want that my loop also work with that timer but my code stuks in that loop and the timer dont run

Present sir

Some code is invisible...

@@samithasilruwan5033 ill show YOU whats not invisible

I'm here watching this with 2K likes and 1K subscribers.

Not me

Yes it is 🥰😅

Generated with python using opencv

hint 2's complements for roll ober

@@ikeabuchi1 it will still fail, the code is checking 'if greater than', it will fail at the roll over, the first iteration after the rollover will fail, unless you check the absolute difference.

"and i have function in a loop" You mean you have a Loop IN A FUNCTION YES YOU CAN DO THAT However, instead of killing yourself with Arduino Why don't you pop over to ESP32 Learn about Multi Tasking thefollowing FREE RTOS COMMANDS xTaskCreate (Focus on this) xTaskCreatePinnedToCore (This is popular but over rated but sometimes useful) if that alone doesn't help you , Learn about Queues Semaphore Mutexes See, Unlike processes in Arduino, In ESP32 You don't do this... void setup() { } void loop() { } Instead you do this void setup() { } void Function1() { YOUR ONE TIME CODE GOES HERE for(;;) { YOUR LOOP CODE GOES HERE } } void loop() { } AND YOU CAN CREATE AS MANY FUNCTIONS AS YOU WANT AND EACH FUNCTION CAN BE ASSIGNED PRIORITY with the following line xTaskCreate(Function_1, "Function 1", 2000, NULL, 1, &Function1 ); The priority is the "1" this will allow you to dictate which programs runs first, second or at all so long as you understand THE TASK STATES OF RTOS www.freertos.org/RTOS-task-states.html Your problem is greatly simplified if you use ESP32 and FreeRTOS In Arduino Functions run BY DEFAULT Sequentially In ESP32 BY DEFAULT Assuming all Functions are set to the same priority THEY ALL EXECUTE AT THE SAME TIME There is nothing for you to set LOL

Yes it will work even when processes depend on each other but having a delay on a process should be avoided for proper functioning.

@@amrit5 Actually I understood and tried it , it works but not as I want because my program depends on the user so I want to make constats of time provided by the function millis() because the millis starts counting when the arduino board is on not when the user send the signal to activate the motors ... but its not possible inside arduino loop funcrion to save the current value of milli time. I am thinking of a solution to save the time inside the loop so I can run the DC motor after the servo complete one rotation using the solution you presented.

There's no problem with it everytime the counter reaches it's MAX_INT it rollover to 0 and continue from there No code crashes

@@mihaiocnaru5260 No code crash problem, but when millis() rolls over to 0 the comparison of the current value of millis() to the pervious will fail to work as intended

​@@akirchner3depends on how you do the comparison. Unsigned integer types in C++ have wrapping overflow semantics. This means that additions that overflow and subtractions that underflow can still give the correct answer as long as you work with delta t and not absolute t values.

Thank you for letting me know. I didn't notice that. It should be >=

Nice hack

Instead of coming here for the answer WHY DON'T YOU GO TO THE ARDUINO FORUM ? I also have some advice for you if you go there 1. THEY EXPECT YOU TO DO YOUR OWN WORK AND RESEARCH THERE 2. They don't like it when you are in school or Uni and say "I have this project...........what's the answer ?" We are not there to do your work for you We are volunteers on the site WE ASSIST YOU........ We don't do the work for you. Remember that important point and you'll be fine 3. When asking a question follow this format - Introduce yourself briefly - Explain what Hardware you are using and What IDE and Version you are using. - Briefly describe the project - Explain your problem IN DETAIL - EXPLAIN WHAT YOU HAVE DONE SO FAR TO TRY TO FIND THE SOLUTION. (if you skip this part, you won't have a pleasant time on that forum) doing this DEMONSTRATES you have done something , and you can't lie because we can tell if you're lying, so make sure YOU ACTUALLY HAVE DONE RESEARCH - Post your code USING THE CODE BUTTON, do not just post it to the forum (if you don't know how, Ask the forum and they will tell you) there is a button at the top called /Code/ Press that . - Provide a schematic of your project, even if it's hand drawn. Don't skip this as they will demand it before you get any answer . If you do those things, you'll get a lot of assistance if you don't you'll probably get told "we don't do your homework for you" also, if your code was written by an A.I. DO NOT POST IT, they hate that . But coming here to get the answer is not the right thing to do

@@martinkuliza U wrote these much words for me, Just to help me. 🥺🥺 OMG, u r such a kind and nice person, who gave his time to guide me. Thanks brother ❤️❤️❤️ Love u from India ❤️

@@RanaRao_Chandrachur "U wrote these much words for me, Just to help me." YES I DID "OMG, u r such a kind and nice person, " YOU'RE WELCOME, THANK YOU Question : Why are you using AT89S52 if that's the problem. is it a course parameter that you need to use this architecture. if yes... WHY ? What's the purpose of doing it if your'e allowed to use another board, i would suggest not Arduino but ESP32 Wroom But if it must be that, then 1 thing you can be certain of is this... THE LECTURER WILL KNOW THAT A SOLUTION EXISTS therefore it can be done The lecturer will have a lesson they want to teach you, Know what the lesson is and you'll be closer to the solution.

@@martinkuliza Actually yes, I was learning At89S52. And I got the solution, I will use RTC using I2C interface. There was a solution with the interrupt and using good crystal but they are not even giving decent results, so I decided to use a RTC ds3231 that is temparature independent, means it automatically resolve it's frequency drift based on inbuilt temperature sensor. Yes Esp is the best option as it syn using internet. And once again Thanks brother stay safe, healthy and happy ❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️

@@RanaRao_Chandrachur You're Welcome... RE "Yes Esp is the best option as it syn using internet." I actually wasn't referring to the internet feature of it... but.. Yes you can do that as well

millis() doesn't stop counting. If you stuck somewhere for 1-2 ms, you'll probably miss it.