WEBVTT 00:00.330 --> 00:07.320 And before we jump into the code, what is how do to interrupt our interaction to understand interrupt? 00:07.500 --> 00:09.930 First, let's see a real life example. 00:10.710 --> 00:16.190 Let's say you are waiting for a package to arrive at your home in order to not meet the package. 00:16.200 --> 00:17.910 You have two choices of action. 00:18.450 --> 00:21.970 First, you can come back every minute to your front door to check in. 00:21.990 --> 00:24.120 The delivery truck is here or not. 00:24.450 --> 00:28.440 And that is called pulling all you can do something else. 00:28.680 --> 00:35.550 And when you hear the doorbell, you interrupt your current activity to open the front door and get 00:35.550 --> 00:36.240 the package. 00:36.660 --> 00:40.010 This is called interrupt or interruption. 00:40.590 --> 00:46.320 And when you work with a push button or a similar digital sensor, this is the same. 00:46.770 --> 00:52.800 You can either check the button state every time you get the change in the loop function or you can 00:52.800 --> 00:59.520 sit up and interrupt to post the execution of the program and call a function as soon as the button 00:59.530 --> 01:07.530 state has changed and interrupt will be triggered by hardware without necessitating the software resources 01:07.530 --> 01:08.270 of the algorithm. 01:08.760 --> 01:13.800 So when the interrupt is triggered, your program is paused and you interrupt. 01:13.800 --> 01:14.880 Function is called. 01:15.390 --> 01:20.600 As soon as your interact function has finished its execution, the program resumes. 01:21.090 --> 01:22.800 So using interrupts. 01:22.800 --> 01:25.620 This is bullying can be a good idea. 01:25.620 --> 01:32.120 For example, if you want to be notified as soon as the button is priced or released, because we've 01:32.130 --> 01:38.250 polling, even if your program goes very fast, you still have to wait for the loop function to finish 01:38.250 --> 01:45.000 out the other instructions of your application between each read of the button state, which may or 01:45.000 --> 01:47.600 may not be a problem in some situation. 01:47.850 --> 01:52.890 And also using interrupts can ensure you that you don't miss the change of the state. 01:53.460 --> 01:55.340 For the example of the package delivery. 01:55.560 --> 02:02.040 Let's say you check every minute, but then if the delivery truck comes in between that minute and just 02:02.040 --> 02:06.720 waits five seconds before leaving, well, you might miss your package. 02:07.300 --> 02:11.670 So, of course, we already know the timing is much quicker for all the action you do. 02:12.010 --> 02:14.460 OK, we are not talking in seconds or minutes. 02:14.460 --> 02:17.420 We will be talking in microseconds or milliseconds. 02:17.820 --> 02:23.510 And by using the time functionalities and not the delay functions, we pulling. 02:23.520 --> 02:27.240 You should not have the problem of missing the change of state. 02:27.750 --> 02:33.120 But the more your program grows and the more instructions you add, which can take some time, the more 02:33.120 --> 02:34.960 chance you have to miss it. 02:35.490 --> 02:42.150 So if what you want to do is to get notified of when the button state changed while also doing many 02:42.150 --> 02:45.810 other things, then using interrupts is actually a good idea. 02:46.170 --> 02:48.540 And actually just a small parenthesis here. 02:48.750 --> 02:51.380 Interrupts are not just for push buttons, ok. 02:51.900 --> 02:58.230 Interrupts can be used whenever you want to monitor the change of the state for a digital pin. 02:58.800 --> 03:02.210 Now what are the triggers for the interrupt function to be called. 03:02.670 --> 03:10.110 So here is a signal that starts low or zero vote and then goes high or five-fold, for example, when 03:10.110 --> 03:16.960 you press the button and then goes back to low when you release the button, the first mode for interrupts 03:16.980 --> 03:19.290 is rising with this mode. 03:19.470 --> 03:26.000 The interrupt will be triggered when the signal goes from low to high and only this. 03:26.400 --> 03:27.990 The second mode is following. 03:28.410 --> 03:30.150 This is the opposite here. 03:30.180 --> 03:34.280 The interrupt will be triggered when the signal goes from high to low. 03:34.950 --> 03:41.340 Then the third mode is change and is actually a combination of rising and fully. 03:42.330 --> 03:48.810 So if you have any of those two, we've changed, the incorrupt will be triggered and finally, default 03:48.810 --> 03:55.620 mode is low, this mode is a little bit different because the interrupt will be triggered whenever the 03:55.620 --> 03:56.700 signal is low. 03:57.000 --> 04:03.420 So it's quite useful when you have a signal that is high all the time and which goes to low only at 04:03.420 --> 04:07.170 some specific moments for a very short duration. 04:07.470 --> 04:10.170 But otherwise, in our case, we are not going to use it. 04:10.590 --> 04:13.700 OK, so to recap, those are the four modes you can choose. 04:13.710 --> 04:17.790 OK, we are going to see how to do that practically in the next. 04:17.790 --> 04:23.790 Listen, so we've rising to interrupt would be triggered when the signal goes from low to high. 04:24.210 --> 04:30.750 We following when the signal goes from high to low changed is the combination of rising and falling 04:31.380 --> 04:33.840 and low is whenever the signal is low. 04:34.530 --> 04:37.590 Now, what other options can you use for interrupts? 04:38.130 --> 04:43.320 Well, first, this is only happening with digital things, not analog bits. 04:43.920 --> 04:46.850 Then it depends a lot on your Arduino model. 04:47.520 --> 04:49.770 Here is a table for the most common ones. 04:50.400 --> 04:55.650 But you can see the outline of, you know, that we have or if you have the Nano or Mini, well, you 04:55.650 --> 04:58.790 only have two digital things you can use for Internet. 04:58.800 --> 05:01.230 And those are pince number two and three. 05:01.770 --> 05:03.210 OK, so only two things. 05:03.210 --> 05:08.790 If you have the Omega Omega, you can see you have much more digital things you can use for interrupts. 05:09.120 --> 05:15.570 OK, then you can see from micro Leonardo then if you have zero are doing, you can use all digital 05:15.570 --> 05:18.720 things except for the PIN number four for the Adeno Zero. 05:19.310 --> 05:25.100 OK, so you can see depending on your application, if you need to use many interrupts, well the algorithm 05:25.500 --> 05:31.980 might not be the best solution, but for what we are going to do now and for the final project of the 05:31.980 --> 05:36.070 course and for many of your project that you are going to start afterwards. 05:36.360 --> 05:37.770 The you know, is quite good. 05:37.810 --> 05:40.470 OK, you can already manage to do a lot of things. 05:40.470 --> 05:41.890 We just two interns. 05:42.210 --> 05:42.660 All right. 05:42.660 --> 05:49.360 So now you have a global understanding of what our interests are and when or why to use them. 05:49.720 --> 05:53.880 No, let's actually use interest in our program.