Using previousTime = currentTime; will introduce an accumulating error. The time to process the code within the if statement will add to the time and accumulate. For just blinking LEDs or some other none critical stuff, no big deal. But if you simply use: previousTime += interval; You've just gotten rid of the cumulative error.
@@programmingelectronics It probably won't affect most of what people will use this for, but it is just the sort of thing to drive you crazy later when you can't figure out why your timing is slipping.
I think Micheal is THE BEST TRAINER out there to learn the basics of programming in Arduino!!! I've spent many hours watching all kinds of Arduino videos before I found Micheal's - Programming Electronics Academy. I signed up and watched ALL of his videos and it was well worth the money!!! I highly recommend it to anyone that is getting into Arduino programming. He is really, really good!!!
I have always struggled with this, even with your videos from years ago. I have watched numerous videos and still struggled. This video is simply THE BEST! You have done so well as an experienced programmer to be able to explain to us newby's how this work is such an easy to understand way. I have been copying & pasting other peoples bits of code randomly getting results and as my projects get more complicated, that approach does not work. Well done, you are the best teacher on TH-cam for Arduino. No.1 Numero uno!
I'm an 'old timer', and after a year of struggling with the theory and even the basic concept of 'millis', I've finally 'got it'! Thank you for the best Arduino 'millis' tutorial, and it's been my good fortune to find it..I look forward to watching more of your videos in future. John.. Bristol.. UK
Smoooth animation bro. I love the homey type design, backdrop is really chill. Casually printing ice ice bb to the serial monitor lol. Explained it fantstic with the carrot comparison. Sending money but more importantly encouragment. Your great at this! keep going - seriously God Bless ;) - J. T
The way you show it will usually work nicely. However, the interval at which you trigger your event will be at least eventInterval, but often just a little bit longer. This is because the loop also takes a little time. Sometimes you may want to be more sure that you always trigger your timed event at an 'exact' multiple of 'eventInterval'. In such cases it's better to update your 'previousTime' with the 'eventInterval', like so: previousTime = previousTime + eventInterval;
Wow this is so excellent. I've been bumping up against limitations imposed by my reluctance to learn this methodology but now I'm halfway through the video and excited about the possibilities this engenders.
love the simplicity you bring into the explanation..... i had been reading up on example codes to understand millis function and scratching my head over and over. I wish i had found this video earlier...
Thanks a lot man! I watched numerous videos, but wasn't able understand the concept of space time along with black holes. But now I'm confident enough to derive E=mc².💪
When you saved me I really love that tutorial it's actually the best thing I've ever watched in the history of our doing it Tori old and I'm not even being hilarious that's the truth thanks man keep up the good work !
One thing that should be added to the code is a trap for when the value of the millis() function rolls over. Consider if your Arduino is being used on a long term basis exceeding the long int value maximum. The user would want a way to handle that condition and continue the event timer. One quick way would be to check if the new millis() time is less than the previous time then the event timer loop can be reset.
@@Ruudrad please explain a bit please. Is it in the code in your face code or firmware side that you simply do not see. As in... If I am using millis to run a tachometer on an engine, and using that tach value to hold ignition on (interlock if you will, if RPM drops it cuts ignition) it will not get the math wrong in seeing the correct rpm? The long term use case here is; the arduino is going to be powered on indefinitely monitoring a signal from inverter to start generator. Once the inverter calls, the arduino will sequence and start the generator. I dont want the roll over to cause am issue with a tach calculation inadvertently shutting down the generator.
@@wadebrewer7212 I initially also thought roll over would cause problems, however if you use longs _and_ subtract the unsigned longs (holding the output of the millis() function and/or the millis() function itself) the calculation will also work when millis() rolls over (I.E. goes from almost its maximum to just over zero). Strange but true thanks to how subtraction works on a microprocessor, which is NOT exactly the same as mathematical subtraction.
@Ruudrad Thank you tons. I was about to start researching for a work around. The community around this stuff is pretty great. Every once in a while you get the tool that talks down or "why do you want to do that project"....because I can....and at least for now...I am allowed.....lol. Even in my situation....reading and counting every quarter or half second for revolutions....even if it did send a call to shut off the system, the cycles are so quick I don't think it would actually shut down. But...sounds is like it's non issue anyway. Again, thank you for the input and much appreciated.
it was taking me forever to figure out why mine wasn't working, then i found out i had "==" instead of ">=" lol thanks for the very clear and concise explanation!
First off, thank you for your very informative video. I know this video is a few years old but I just came across it so my apologies for such a late comment. From your video, and from others, I understand that millis() starts as soon as the Arduino starts running and it keeps running, and increasing, as long as the Arduino is up, at least until it reaches its maximum value and restarts. I'm not sure that you actually CAN reset millis() from within code but everyone seems to say you shouldn't. Apparently doing so can break some libraries that rely on it. In order to understand millis() better I made a little project using code similar to yours to blink the built-in LED on and off at a preset interval while displaying current_elapsed_time (read from millis()) and previous_time, something similar to what you did in your code, and everything ran as expected. However, I noticed that every time I closed the serial monitor and reopened it the current_elapsed_time, which should display the current millis() value, returned to its starting value. The LED continues to blink at the proper interval while the monitor is closed, so I know the code is still running properly. Thinking there was a bug in my code I created a new, stripped-down program which only makes a call to millis() and prints the retrieved value to the serial monitor (see code below) and ran my test again. Same behavior. The code calls for the millis() value to be sent to the serial monitor directly - no massaging or assigning to a variable - and every time I close and reopen the serial monitor it appears to reset millis(). Not sure what is happening. Here is the simplified code I used to test: void setup() { Serial.begin(115200); } void loop() { Serial.println(millis()); } The program runs as expected and, as you can see, there is nothing but the call to print the current value of millis() but millis() seems to be affected by the status of the serial monitor window. Is this normal? Am I missing something? 🤔 Appreciate your help on this. Thank you.
Hi! I'd like to thank you very much for the excelent explanation! I was struggling a bit with millis() until watched you videos. It saved me a lot of time and helped me to understand why my project wasn't working (that's the best way to learn something, by fixing it's bugs)! Keep on doing this awesome job, man!
Very Cool!! You come out with this video just in time for me to use millis() to toggle between volts and amps on an OLED display (without using delays, delays that long when added up would have made the loop way too long for this project). It took me a bit to figure out how to write the second section (like this:) (currentTime - previousTime >= interval + interval_1) I added the second interval time so I could set the volts code to display less time than the amps code since that's the one that needs to be read the most, but I got it. I'm sure I will eventually figure out an easier way but it's good for now and I'm proud of it! :-D The most valuable information in your video series is the fact that the timer continues to count up until the microcontroller is reset or turned off and on again. I now also realize that I can run more than one program from the same millis() function. It's kind of like calculating what needs to happen at different times of the day with a certain amount of time for each task. Yeah, I know, probably a screwed up analogy but there it is LOL :-) Until now I thought that the timer reset each time it was called for. Thanks!! Joe
I think this is good idea if you need to step multiple stepper motors at the same time. When using delay() for moving stepper motors you can only move one stepper motor at a time
wow that's awesome and well explained ! The presentation is very nice and clean and understandable ! but... what is it again ? ah, needs to rewind this utube vlog again & again.
Great video, thanks! One comment though, I think we could also use a modulus operator to manage the event intervals. This would also cause it to run at millis() == 0, but we can use an additional clause to limit this. Perhaps something like: if( currentTime > 0 && currentTime % eventInterval == 0 ) { ...
Actually, it seemed like this would work in theory, but there needs to be a buffer, as the code would run multiple times at each interval. I guess this is why the lastTime variable is introduced, so that we can ensure the code runs only once per interval. Makes sense - I stand corrected!
Thanks for the extensive explenation. I made function out of this, which can receive interval in milliseconds and counter number, so it can be called multiple times and keep prevousTime in array for multiple counters. if(execDelay(2,1000)) { // Do stuff } bool execDelay(int instance, unsigned long v) { unsigned long prevTime[] = {}; if(currTime - prevTime[instance] >= v) { prevTime[instance] = currTime; return true; } else { return false; } }
Hey Programming Electronics Academy. Your code is good if you want 1000 milliseconds between events, which ie. takes 10 milliseconds to execute. However. If you want things to happen every 1000 milliseconds, sharp, then you will need to add 1000 to the carrot, instead of moving ahead with the relative time. You can say, that you would add 1000 to the limit of 1000 every time, making an absolute goal, rather than adding to the relative currentTime.
Same idea…. Slightly different solution: if(millis() % 1000 == 0)) { // make your fish taco } IOW use modulus operator… any number divided by 1000, then take the remainder. When remainder is zero, millis is a multiple of 1000. Also: You can make an LED ‘flicker’ by using the random function to change the 1000.
This is a bad idea for two reasons: 1. If your loop() ever takes more than one millisecond to run, you may well miss the specific millisecond you where aiming for. 2. millis() doesn't count every single millisecond: as it is only updated every 1024 µs, it skips one value roughly every 42.7 ms (it skips 42, 85, 127, 170, 213, etc.).
you could do the same logic and prob have better runtime using (inside the loop) if (millis() % interval == 0) { // do whatever you want here for every x amt of milliseconds // where x = interval }
In an Ideal situation, you're right. But in reality millis would almost never hit exactly your interval. That's why >= is used in the video, but with your code >= wouldn't work.
We dont have to crate a variable(previousTime) if we only wanna execuit the if once.but to update the timing we have to substract the (currentTime from the previousTime)
Amazing explanation, great thanks. Thus, there is something I don't manage to understand. If I want a start point not equal to the interval, I mean for example an event to start at 30 seconds, and to be repeated 60 seconds later on. Do I need one more variable to be created? Kind regards.
How do you handle the overflow of the millis function ? Like this, code will run fine for 49 days and then stop working. You cannot be sure what exactly previoustime will be the last time the event occurs before overflow because of small inaccuracies that will sum up until the 49 days mark Somehow you need to know when to reset previous time without loosing information about the time lapsed since the last event This is a purely hypothetical example, but lets say ypu are building an arduino based pacemaker - you absolutely need to always reliably trigger a pulse at the same intervals, while sending some data like battery percentage etc to an external host or whatever How do you prevent the device from missing or falsely timing an event after 49 days?
The fact that you are using unsigned long for currentTime, previousTime, and interval makes the subtraction wrap around and work correctly. No need to reset the millis() timer. if (currentMillis - previousMillis >= interval) {
//when currentMillis wraps around and previousMillis subtracts, the //answer is likewise wrapped back around and the difference is correct previousMillis += interval; // does not accumulate timing errors
Helloo, if currentTime = "MAXIMUM of millis()" then next currentTime(or next value of millis() ) will be : Case 1 : or remaining to "MAXIMUM of millis()" or Case 2: next value will be 0.Which case do you think that will happened?. If Case 1: currentTime = "MAXIMUM of millis()" minus previousTime (which it will be olso "MAXIMUM of millis()") = 0 (so, the difference will be zero and all the time will not >= SetTime. IfCase 2: if millis after 49 days will be automatically 0 then difference 0 - "MAXIMUM of millis()" ('the last value of previusTime) will be negative , so, in this case it a must to use all the time ABS(currentTime-PreiousTime) >=SetTime. So which case it happening!? An alternative solution is to use a function to reset automatically arduino ( I tested this function: void(* resetFunction) (void)=0; and, after, in loop rutine call this function using: resetFunction(); if millis()>=4000000000UL ....resetFunctio() .. .This resetFunction is very fast.Write , as example, Serial.print(F("abc..")); after calling resetFunction(); and you will see that Serial.print(F("abc..")); will not happened because arduino it was reset be resetFunction(); OR, if someone cand wait ~ 49 days to see what happend with value of millis() function after this period , please let me know :)) .Maybe will happened one of both cases 1 or 2 ...or neither.
Why not use the modulus function? If (currentTime % eventInterval == 0). It wouldn't be precise on the rollover (unless the interval was a power of 2) but it allows for lots of different intervals with minimal code.
With millis() the serial data continues to be read, where previously it was clear to see on the Serial Monitor that delay had simply frozen it dead for the length of the delay.
Very nicely and clearly explained. I made the same comment elsewhere - going forward, when using millis() function, please DO NOT call any assigned variable as currentTime and previousTime or "timestamp" - it is not a time. It really is a timeline from 0 to 4B+ value. I see this problem in all the TH-cam examples where they explain millis(). Everybody should really call it CurrentTimeLine or currentTimeLine or something similar, NOT currentTime or previousTime. Does that make sense?
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please make a video on arduino sensor kit i need help on it btw your videos are amazing
Using
previousTime = currentTime;
will introduce an accumulating error. The time to process the code within the if statement will add to the time and accumulate. For just blinking LEDs or some other none critical stuff, no big deal.
But if you simply use:
previousTime += interval;
You've just gotten rid of the cumulative error.
Thanks for bringing this up Steve!
@@programmingelectronics It probably won't affect most of what people will use this for, but it is just the sort of thing to drive you crazy later when you can't figure out why your timing is slipping.
This is a great explanation. The visuals really help wrap your head around the concept. Thanks for the vid!
Thanks for watching!
This is the best "millis()" tutorial I have ever seen. Thanks so much for explaining everything clearly.
Glad it was helpful! Thanks so much for the note!
I think Micheal is THE BEST TRAINER out there to learn the basics of programming in Arduino!!! I've spent many hours watching all kinds of Arduino videos before I found Micheal's - Programming Electronics Academy. I signed up and watched ALL of his videos and it was well worth the money!!!
I highly recommend it to anyone that is getting into Arduino programming. He is really, really good!!!
Thanks so much for the kind words John! I am glad you are finding the training helpful!
I have always struggled with this, even with your videos from years ago. I have watched numerous videos and still struggled. This video is simply THE BEST!
You have done so well as an experienced programmer to be able to explain to us newby's how this work is such an easy to understand way.
I have been copying & pasting other peoples bits of code randomly getting results and as my projects get more complicated, that approach does not work.
Well done, you are the best teacher on TH-cam for Arduino.
No.1
Numero uno!
I'm an 'old timer', and after a year of struggling with the theory and even the basic concept of 'millis', I've finally 'got it'!
Thank you for the best Arduino 'millis' tutorial, and it's been my good fortune to find it..I look forward to watching more of your videos in future.
John.. Bristol.. UK
Excellent! Great to hear John!
Smoooth animation bro. I love the homey type design, backdrop is really chill. Casually printing ice ice bb to the serial monitor lol. Explained it fantstic with the carrot comparison. Sending money but more importantly encouragment. Your great at this! keep going - seriously
God Bless ;)
- J. T
Appreciate that - thanks for your generosity J.T.!
The way you show it will usually work nicely. However, the interval at which you trigger your event will be at least eventInterval, but often just a little bit longer. This is because the loop also takes a little time. Sometimes you may want to be more sure that you always trigger your timed event at an 'exact' multiple of 'eventInterval'. In such cases it's better to update your 'previousTime' with the 'eventInterval', like so:
previousTime = previousTime + eventInterval;
That's a fantastic point - thanks for that adding that Jan!
Wow this is so excellent. I've been bumping up against limitations imposed by my reluctance to learn this methodology but now I'm halfway through the video and excited about the possibilities this engenders.
Great! Timing can be a bear. Another thing you might consider is learning about RTOS for scheduling tasks.
love the simplicity you bring into the explanation..... i had been reading up on example codes to understand millis function and scratching my head over and over. I wish i had found this video earlier...
Glad it helped!
I like that the if statement works even when the counter overflows so it'll keep going after 49 days and not miss a beat.
The best explanation I've ever seen about millis()
true
GOD BLESS YOU! You saved me from days of suffering! You are my Hero!!!
Glad it helped!
Thanks a lot man!
I watched numerous videos, but wasn't able understand the concept of space time along with black holes.
But now I'm confident enough to derive E=mc².💪
Glad it helped :)
The best explanation ever... the carrot example was just epic... every noob can understand..... thank you so much for the great tutorial.
Glad it helped!
Amazing explanation and visuals to illustrate the more abstract concepts, cheers!
Thanks for the note! I hope it helped.
When you saved me I really love that tutorial it's actually the best thing I've ever watched in the history of our doing it Tori old and I'm not even being hilarious that's the truth thanks man keep up the good work !
what a Legend ! i wish i would of found your videos earlier! Absolutely the best explanation of things. Thank you Sir!
Thanks a ton! Glad they were helpful.
Oh you did great. This will help me on the annoying issue between RF transmitter not sending data because pulse sensor eats all the event
Great! Glad it helped!
One thing that should be added to the code is a trap for when the value of the millis() function rolls over. Consider if your Arduino is being used on a long term basis exceeding the long int value maximum. The user would want a way to handle that condition and continue the event timer. One quick way would be to check if the new millis() time is less than the previous time then the event timer loop can be reset.
The way the code is written, by subtraction of unsigned longs, it compensates for roll over. No additional checks are needed.
I was just wondering about rollover
@@Ruudrad please explain a bit please. Is it in the code in your face code or firmware side that you simply do not see. As in...
If I am using millis to run a tachometer on an engine, and using that tach value to hold ignition on (interlock if you will, if RPM drops it cuts ignition) it will not get the math wrong in seeing the correct rpm?
The long term use case here is; the arduino is going to be powered on indefinitely monitoring a signal from inverter to start generator. Once the inverter calls, the arduino will sequence and start the generator. I dont want the roll over to cause am issue with a tach calculation inadvertently shutting down the generator.
@@wadebrewer7212 I initially also thought roll over would cause problems, however if you use longs _and_ subtract the unsigned longs (holding the output of the millis() function and/or the millis() function itself) the calculation will also work when millis() rolls over (I.E. goes from almost its maximum to just over zero). Strange but true thanks to how subtraction works on a microprocessor, which is NOT exactly the same as mathematical subtraction.
@Ruudrad Thank you tons. I was about to start researching for a work around. The community around this stuff is pretty great. Every once in a while you get the tool that talks down or "why do you want to do that project"....because I can....and at least for now...I am allowed.....lol.
Even in my situation....reading and counting every quarter or half second for revolutions....even if it did send a call to shut off the system, the cycles are so quick I don't think it would actually shut down. But...sounds is like it's non issue anyway.
Again, thank you for the input and much appreciated.
it was taking me forever to figure out why mine wasn't working, then i found out i had "==" instead of ">=" lol
thanks for the very clear and concise explanation!
Thanks a ton for watching - I am glad it helped!
First off, thank you for your very informative video. I know this video is a few years old but I just came across it so my apologies for such a late comment.
From your video, and from others, I understand that millis() starts as soon as the Arduino starts running and it keeps running, and increasing, as long as the Arduino is up, at least until it reaches its maximum value and restarts. I'm not sure that you actually CAN reset millis() from within code but everyone seems to say you shouldn't. Apparently doing so can break some libraries that rely on it.
In order to understand millis() better I made a little project using code similar to yours to blink the built-in LED on and off at a preset interval while displaying current_elapsed_time (read from millis()) and previous_time, something similar to what you did in your code, and everything ran as expected. However, I noticed that every time I closed the serial monitor and reopened it the current_elapsed_time, which should display the current millis() value, returned to its starting value. The LED continues to blink at the proper interval while the monitor is closed, so I know the code is still running properly.
Thinking there was a bug in my code I created a new, stripped-down program which only makes a call to millis() and prints the retrieved value to the serial monitor (see code below) and ran my test again. Same behavior. The code calls for the millis() value to be sent to the serial monitor directly - no massaging or assigning to a variable - and every time I close and reopen the serial monitor it appears to reset millis(). Not sure what is happening.
Here is the simplified code I used to test:
void setup() {
Serial.begin(115200);
}
void loop() {
Serial.println(millis());
}
The program runs as expected and, as you can see, there is nothing but the call to print the current value of millis() but millis() seems to be affected by the status of the serial monitor window. Is this normal? Am I missing something? 🤔
Appreciate your help on this.
Thank you.
Best explanation ever on millis. Thanks alot bro
Thanks! Glad it helped!
You are my favourite teacher.
Thanks a bunch 😀
Hi! I'd like to thank you very much for the excelent explanation! I was struggling a bit with millis() until watched you videos. It saved me a lot of time and helped me to understand why my project wasn't working (that's the best way to learn something, by fixing it's bugs)! Keep on doing this awesome job, man!
Thanks so much for the note Leonardo!
You make everything look simple .
Thanks
I hope it helped! Timing stuff can get confusing quick!
Thank you for a wholesome explanation! Great stuff!
why cant every tutorial be like this. Love it best
Very clear explanation - I like that. I have taught some stuff in my one past life...Good job!
You really have easily way to explain each point,thanks
Thank you! I hope it helped!
Very Cool!!
You come out with this video just in time for me to use millis() to toggle between volts and amps on an OLED display (without using delays, delays that long when added up would have made the loop way too long for this project).
It took me a bit to figure out how to write the second section (like this:) (currentTime - previousTime >= interval + interval_1) I added the second interval time so I could set the volts code to display less time than the amps code since that's the one that needs to be read the most, but I got it. I'm sure I will eventually figure out an easier way but it's good for now and I'm proud of it! :-D
The most valuable information in your video series is the fact that the timer continues to count up until the microcontroller is reset or turned off and on again.
I now also realize that I can run more than one program from the same millis() function.
It's kind of like calculating what needs to happen at different times of the day with a certain amount of time for each task. Yeah, I know, probably a screwed up analogy but there it is LOL :-)
Until now I thought that the timer reset each time it was called for.
Thanks!!
Joe
Thanks also for sharing your addition on the code - very cool!
These lessons are so well done!!
Thanks so much Chad - really appreciate that!
Wow.. That was the greatest tutorial I have ever seen on youtube...Thank you...
Glad you enjoyed it!
It becomes very easy to learn from you. You make everything looks so simple. Thanks
Excellent explanation and coding, with great visuals 👏
Thanks so much!
Really a great video.great people behind this Job...The visuals make everything so simple.thanks millions
Really appreciate that! Thanks!
😄 The millis code was smart. I love that logic
I think this is good idea if you need to step multiple stepper motors at the same time. When using delay() for moving stepper motors you can only move one stepper motor at a time
This is awesome! the best explanation ever about millis function. Thanks a lot... Poor millis can't catch the carrot XD
You're mean, Emmanuel!
Thanks you make it so easy to learn
Thanks - much appreciated!
wow that's awesome and well explained ! The presentation is very nice and clean and understandable ! but... what is it again ? ah, needs to rewind this utube vlog again & again.
the best tutorial on millis() ever... thanks...
Thank you!
This detail on the mills() function has been very helpful to me, explains why a program I wrote a few years ago doesn't quite work as expected.
Awesome - I am glad it helped!
Very entertaining channel, love your videos, keep them coming
Thanks - much appreciated!
Great video. Thanks a lot for making this video.
Thank you! Thanks so much for watching!
enjoying this lessons. motivated to keep moving further. thanks a bunch.
Great to hear!
Great. first time explained, first-time understood. thank you very much
Awesome!
Great video, thanks! One comment though, I think we could also use a modulus operator to manage the event intervals. This would also cause it to run at millis() == 0, but we can use an additional clause to limit this. Perhaps something like:
if( currentTime > 0 && currentTime % eventInterval == 0 ) { ...
Actually, it seemed like this would work in theory, but there needs to be a buffer, as the code would run multiple times at each interval. I guess this is why the lastTime variable is introduced, so that we can ensure the code runs only once per interval. Makes sense - I stand corrected!
Very nice and easy to understand video, thanks!
Thanks for watching!
Thank you,
That saved my life ❤
Glad it helped!
Thanks for the extensive explenation.
I made function out of this, which can receive interval in milliseconds and counter number, so it can be called multiple times and keep prevousTime in array for multiple counters.
if(execDelay(2,1000)) {
// Do stuff
}
bool execDelay(int instance, unsigned long v) {
unsigned long prevTime[] = {};
if(currTime - prevTime[instance] >= v) {
prevTime[instance] = currTime;
return true;
} else {
return false;
}
}
Cool! Thanks for sharing that code!
Just one correction, define prevTime outside the function.
@5:31 Aah, I see what you did there: The Neutron Dance! 😆
Hey Programming Electronics Academy. Your code is good if you want 1000 milliseconds between events, which ie. takes 10 milliseconds to execute. However. If you want things to happen every 1000 milliseconds, sharp, then you will need to add 1000 to the carrot, instead of moving ahead with the relative time. You can say, that you would add 1000 to the limit of 1000 every time, making an absolute goal, rather than adding to the relative currentTime.
Very clear and simple explanation . Thank you!!
haha.. being mean with the carrot and millis() function. love it.
Thanks so much for watching!!
I found your video very helpful. Thank you!
Thanks so much for watching Anita!
thankyou so much ,it was a really big help
Great to hear!
Same idea…. Slightly different solution:
if(millis() % 1000 == 0))
{
// make your fish taco
}
IOW use modulus operator… any number divided by 1000, then take the remainder. When remainder is zero, millis is a multiple of 1000.
Also: You can make an LED ‘flicker’ by using the random function to change the 1000.
This is a bad idea for two reasons:
1. If your loop() ever takes more than one millisecond to run, you may well miss the specific millisecond you where aiming for.
2. millis() doesn't count every single millisecond: as it is only updated every 1024 µs, it skips one value roughly every 42.7 ms (it skips 42, 85, 127, 170, 213, etc.).
Simply grand.
Great explanation sir thank you 😁❤
Thanks for this great explanation..it really helps a lot...
this is legendary! massive Thanks
Thanks!
Tyyyy this was such a good video 😄
Glad you liked it!! Thanks so much for watching!
Nice info, well done, thanks for sharing it :)
Thanks for watching!
thankyou, I needed this
You are awesome, I can't wait for the next video! 👍👍
Thanks!
Very nice explaination. Thanks
Glad you liked it! Thanks for watching!
you could do the same logic and prob have better runtime using (inside the loop)
if (millis() % interval == 0) {
// do whatever you want here for every x amt of milliseconds
// where x = interval
}
In an Ideal situation, you're right. But in reality millis would almost never hit exactly your interval. That's why >= is used in the video, but with your code >= wouldn't work.
Great video
Thanks!
This is very informative
Glad it was helpful!
amazing explanationnnnnn
Thanks!
Great video, thank you. Question, will that code work correctly when millis() overflows and starts counting up from zero?
the best explain tutorial lesson thanks a lot 👍
Superb explanation
Thanks so much for the note and for watching
Great video! Going to implement it to my project ASAP
Thank you! I am glad it helped - best of luck!
very well explained, thx
Glad it was helpful! Thank you for watching!
That actually make sanse,Thanks for the vod.
We dont have to crate a variable(previousTime) if we only wanna execuit the if once.but to update the timing we have to substract the (currentTime from the previousTime)
This is a great explanation.
Sweet explanation :) Thank you
Glad it was helpful! Thanks for watching!
The best lesson!
Amazing explanation, great thanks. Thus, there is something I don't manage to understand. If I want a start point not equal to the interval, I mean for example an event to start at 30 seconds, and to be repeated 60 seconds later on. Do I need one more variable to be created? Kind regards.
How do you handle the overflow of the millis function ? Like this, code will run fine for 49 days and then stop working.
You cannot be sure what exactly previoustime will be the last time the event occurs before overflow because of small inaccuracies that will sum up until the 49 days mark
Somehow you need to know when to reset previous time without loosing information about the time lapsed since the last event
This is a purely hypothetical example, but lets say ypu are building an arduino based pacemaker - you absolutely need to always reliably trigger a pulse at the same intervals, while sending some data like battery percentage etc to an external host or whatever
How do you prevent the device from missing or falsely timing an event after 49 days?
See forum.arduino.cc/index.php?topic=122413.0, in particular message #2 & #10 and also www.baldengineer.com/arduino-how-do-you-reset-millis.html
The fact that you are using unsigned long for currentTime, previousTime, and interval makes the subtraction wrap around and work correctly. No need to reset the millis() timer.
if (currentMillis - previousMillis >= interval) {
//when currentMillis wraps around and previousMillis subtracts, the
//answer is likewise wrapped back around and the difference is correct
previousMillis += interval; // does not accumulate timing errors
Helloo, if currentTime = "MAXIMUM of millis()" then next currentTime(or next value of millis() ) will be : Case 1 : or remaining to "MAXIMUM of millis()" or Case 2: next value will be 0.Which case do you think that will happened?.
If Case 1: currentTime = "MAXIMUM of millis()" minus previousTime (which it will be olso "MAXIMUM of millis()") = 0 (so, the difference will be zero and all the time will not >= SetTime.
IfCase 2: if millis after 49 days will be automatically 0 then difference 0 - "MAXIMUM of millis()" ('the last value of previusTime) will be negative , so, in this case it a must to use all the time ABS(currentTime-PreiousTime) >=SetTime.
So which case it happening!?
An alternative solution is to use a function to reset automatically arduino ( I tested this function:
void(* resetFunction) (void)=0; and, after, in loop rutine call this function using: resetFunction();
if millis()>=4000000000UL ....resetFunctio() .. .This resetFunction is very fast.Write , as example, Serial.print(F("abc..")); after calling resetFunction(); and you will see that Serial.print(F("abc..")); will not happened because arduino it was reset be resetFunction();
OR, if someone cand wait ~ 49 days to see what happend with value of millis() function after this period , please let me know :)) .Maybe will happened one of both cases 1 or 2 ...or neither.
Muchas gracias, At last someone took the time to explain this, I really needed it thank you kind GOD of code..
Glad it helped!
very interesting, a good teacher
Thank you!
Thank you sir i really appreciate that....😎😎
Wow, you're the best!!! thanks!
fantastic video!thank you!
Thanks for watching!
Such a nice video 🙂
What a great video.
Thank you! I hope it helped!
Why not use the modulus function? If (currentTime % eventInterval == 0). It wouldn't be precise on the rollover (unless the interval was a power of 2) but it allows for lots of different intervals with minimal code.
Thank you very much Sir... Great Video
Thanks!
Took a while to get millis() working in my code but so much better than using delay.
Nice!
With millis() the serial data continues to be read, where previously it was clear to see on the Serial Monitor that delay had simply frozen it dead for the length of the delay.
so nicely explain thank you :)
Thanks for watching!
thank you
Thank you so much 🤍
+ extra points from ice ice baby
Very nicely and clearly explained. I made the same comment elsewhere - going forward, when using millis() function, please DO NOT call any assigned variable as currentTime and previousTime or "timestamp" - it is not a time. It really is a timeline from 0 to 4B+ value. I see this problem in all the TH-cam examples where they explain millis(). Everybody should really call it CurrentTimeLine or currentTimeLine or something similar, NOT currentTime or previousTime. Does that make sense?
wow its amazing...
Thanks for watching!
Thanks mate
I hope it helped!
very informative...thanks a lot...