Arduino while millis

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arduino while millis

It only takes a minute to sign up. I need to read a sensor every five minutes, but since my sketch also has other tasks to do, I cannot just delay between the readings.

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There is the Blink without delay tutorial suggesting I code along these lines:. The problem is that millis is going to roll over back to zero after roughly Since my sketch is intended to run for longer than that, I need to make sure the rollover does not make my sketch fail. Your example code from the tutorial is fine.

If you try to detect the rollover in order to implement corrective measures, chances are you are doing something wrong. Then, and even if the program is meant to run for years at a time, the millis rollover should not be a concern. The correct way to manage or rather, avoid having to manage the rollover problem is to think of the unsigned long number returned by millis in terms of modular arithmetics. For the mathematically inclined, some familiarity with this concept is very useful when programming.

You can see the math in action in Nick Gammon's article millis overflow For those who do not want to go through the computational details, I offer here an alternative hopefully simpler way of thinking about it. It is based on the simple distinction between instants and durations. As long as your tests only involve comparing durations, you should be fine.

Note on micros : Everything said here about millis applies equally to microsexcept for the fact that micros rolls over every When dealing with time, we have to make the distinction between at least two different concepts: instants and durations. An instant is a point on the time axis. A duration is the length of a time interval, i. The distinction between these concepts is not always very sharp in everyday language.

Keeping the distinction in mind is important, because it is the simplest way to entirely avoid the rollover problem.

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The return value of millis could be interpreted as a duration: the time elapsed from the start of the program until now.Pages: [1]. IamFof Sr. Guys and gals I am getting square eyes trying to find out a way to do something. Initially I tried: Code: [Select]. Re: while and millis. Quote from: IamFof on Mar 14,am. Code: [Select]. Keep Arduino stuff out on the boards where it belongs. I tried both of these: Code: [Select]. Tomorrow's another day and I shall look and think on it then.

I did change val to unsigned long and it still returned 0. Something else to think on. When you come back, your first mission is to post a complete code that demonstrates the issue.

No more snippets.

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Last used C in anger - ooh - about ' At what point are you calling the millis function? Just use IF Have a look at how millis is used to manage timing without blocking in Several things at a time Two or three hours spent thinking and reading documentation solves most programming problems.

Good morning all. Robin2 I realise that while will block the sketch, but that is of no concern in this application. Once finished, the project will sit for several months, basically doing nothing, other than looking at sensors.

Every 15 mins, using if currentMillis, etc it will read all the sensors and write to the SD card. Then back to just monitoring the sensors. I shouldn't push my 72yr old brain too hard, late at night. Up to this point, all seems to be functioning as I expect it to, apart from this blinking LED which is just to indicate that the interval between writes is up and the card is being written to, so do not remove. The function storeData is not complete, yet, as it is still a work-in-progress.

I expect that the sketch will be considered somewhat long-winded and verbose, and can be written much more elegantly, but as this is only my second sketch, I can live with that. I am using a Uno, but for the final, I will have to migrate to a Mega, as I need more pins for the sensors than the Uno provides. I have attached the sketch, as it is too long to go in the code tags.

Further to this flashing LED problem I am having. So I amended it to use a do Quote from: PaulMurrayCbr on Mar 14,am. Quote from: IamFof on Mar 15,pm. As I will need to use the flashing LEDs in more than one place, I will use the function, but I would still like to understand why one worked and the other didn't. At this end, the whole project has had to go on hold, as I have had relatives turn up.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I hope you can help me with my Problem. I want to restart an Animation on any point with pushing a button.

I was able to create another millis sample to work without the normal delay, but the sequenz must finish to start it again. Rather than doing the whole animation in a single iteration of loopI suggest doing only a single step par iteration. Then you need a static or global variable to remember at which point in the animation you are. Resetting the animation on a button press is then just a matter of resetting that state:.

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Question feed. Stack Overflow works best with JavaScript enabled.Pages: [1]. Hi all, So since accelstepper function run has to be called continuously, I used while loop instead of if to make 2 stepper motors rotate at the same time.

However, for a while loop, the codes run longer than coded I made 5 loops similar to the on below but with different time loop Code: [Select]. Code: [Select]. Trying to get back into electronics after 15 years absence. Re: millis in while loop for accelstepper. Compare Code: [Select]. If you understand an example, use it. If you don't understand an example, don't use it. Electronics engineer by trade, software engineer by profession. It works now thanks a lot! However, in the fourth loop, the motors rotate the opposite direction I coded them for 1 or 2 rev before rotating the way I want.

Is it some silly mistakes again? And I copied the draft instead of the real one. I will reupload it Code: [Select]. If the stepper movements need ever happen only once when the Arduino is powered up or reset then why bother putting the code in loop when it could just as well go in setup? Please do not send me PMs asking for help.

Post in the forum then everyone will benefit from seeing the questions and answers. Quote from: Tyloren on Oct 08,am. Two or three hours spent thinking and reading documentation solves most programming problems. Hi Robin, I am trying to make the 2 stepper motors run at the same time so stepper. The project requires me to do the following in order 1. Run DC motor using stepper shield v2 4. Run the first 2 steppers again 5. It stops running the steppers in the while loop I made even tho the codes did get in the loop.

It skipped to the next delay since I used delay for DC motor. If you want to run several motors at the same time and don't need acceleration then use runSpeed.

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If you want to be able to stop calling that so as to stop the motor then create a little function for each motor and in the function check if the motor may run.

Then all you have to do is change the variable elsewhere in your program when you want the motor to go or stop. Something like this Code: [Select]. Thanks for the replies Robin! I made functions like you recommended. I ran into a new problem where after activating the DC motor, the functions made for steppers did not work despite working before using DC motor. What you have in Reply 7 is not remotely like what I suggested in Reply 6.

Of course you are perfectly free to ignore my advice.Sometimes you want everything in the program to stop while a given condition is true. You can do this using a while loop. This example shows how to use a while loop to calibrate the value of an analog sensor. In the main loop, the sketch below reads the value of a photoresistor on analog pin 0 and uses it to fade an LED on pin 9. But while a button attached to digital pin 2 is pressed, the program runs a method called calibrate that looks for the highest and lowest values of the analog sensor.

When you release the button, the sketch continues with the main loop. This technique lets you update the maximum and minimum values for the photoresistor when the lighting conditions change.

Connect your analog sensor e. Connect your button to digital pin, again with a 10K ohm resistor to ground.

arduino while millis

Connect your LED to digital pin 9, with a ohm resistor in series. For more circuit examples, see the Fritzing project page. While the pushbutton is pressed, the sketch runs the calibration routine. This is a variation on the calibrate example. Arduino or Genuino Board pushbutton or switch photoresistor or another analog sensor 2 10k ohm resistors breadboard.Sometimes you need to do two things at once.

For example you might want to blink an LED while reading a button press. In this case, you can't use delaybecause Arduino pauses your program during the delay. If the button is pressed while Arduino is paused waiting for the delay to pass, your program will miss the button press. This sketch demonstrates how to blink an LED without using delay.

It turns the LED on and then makes note of the time. Then, each time through loopit checks to see if the desired blink time has passed. If it has, it toggles the LED on or off and makes note of the new time. In this way the LED blinks continuously while the sketch execution never lags on a single instruction. An analogy would be warming up a pizza in your microwave, and also waiting some important email.

You put the pizza in the microwave and set it for 10 minutes. The analogy to using delay would be to sit in front of the microwave watching the timer count down from 10 minutes until the timer reaches zero. If the important email arrives during this time you will miss it.

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What you would do in real life would be to turn on the pizza, and then check your email, and then maybe do something else that doesn't take too long!

To build the circuit, connect one end of the resistor to pin 13 of the board. Connect the long leg of the LED the positive leg, called the anode to the other end of the resistor.

Connect the short leg of the LED the negative leg, called the cathode to the board GND, as shown in the diagram above and the schematic below. If you run this example with no hardware attached, you should see that LED blink.

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For more circuit examples, see the Fritzing project page. After you build the circuit plug your board into your computer, start the Arduino Software IDEand enter the code below. The code below uses the millis function, a command that returns the number of milliseconds since the board started running its current sketch, to blink an LED.Pages: [1]. Issue with millis in a while loop. Hi all, I'm trying to write a while loop that will break out of the loop after a certain amount of time using the millis function.

This is a simplified version of what I'm doing, which does't seem to work: Code: [Select]. Re: Issue with millis in a while loop. Yes, 1. Try a while where the while is checked first. Hi Mark, thanks for the reply. I see what you mean and that is clearly an issue with this simple example.

Arduino delay() and millis() Functions: Tight Loops and Blocking Code

However in my actual program the loop is proceeded by more code which should be executed when the loop exits, which it doesn't. Anyway I've changed the example as you say and now strangely I don't get anything at all printed in the monitor: Code: [Select].

Quote from: holmes4 on Jan 16,pm. Thanks all, clearly some school boy errors on my part. Here is the actual loop from my program as opposed to the test above : Code: [Select]. Quote from: markbeverley on Jan 16,pm.

Code: [Select]. Hi Ken, miclevel is essentially a microphone attached to an analogue input. If miclevel does not exceed SoundThresh within 2 seconds then the loop should also finish but it doesn't. Two or three hours spent thinking and reading documentation solves most programming problems. No technical PMs.

arduino while millis

If you are asked a question, please respond with an answer. If you are asked for more information, please supply it.

If you need clarification, ask for help. Quote from: LarryD on Jan 16,pm.