WEBVTT 00:00.180 --> 00:05.940 Let's first understand what the problem is for that, they will simply start with an example where you 00:05.940 --> 00:08.460 will clearly see the button bouncing. 00:08.850 --> 00:14.880 So what we're going to do is to try to monitor the push-Button, but not just when it's high or when 00:14.880 --> 00:15.800 it's low equity. 00:15.810 --> 00:21.120 Previously, we are going to monitor the push-Button so we can detect a change of state. 00:21.910 --> 00:27.300 This is the most common use case for anybody when you detect a change of state, which means that, 00:27.300 --> 00:34.490 for example, the user presses the button so the state will go from low to high in the circuit. 00:34.500 --> 00:35.640 We have all that. 00:35.670 --> 00:39.420 You simply release the button and the state will go from high to low. 00:39.930 --> 00:45.470 And this is this exact change of state that we want to monitor, not just all the time. 00:45.480 --> 00:47.150 The button is high all the time. 00:47.160 --> 00:47.890 The button is low. 00:48.420 --> 00:54.360 Well, let's make a simple example to monitor the change of the state of the button and print it on 00:54.360 --> 00:55.200 the side of the monitor. 00:55.830 --> 01:02.620 So first, I'm going to initialize the define button in two. 01:02.710 --> 01:03.930 OK, so as usual. 01:05.700 --> 01:08.880 Because we are going to use Cyril, I'm going to say begin. 01:11.550 --> 01:14.070 It with these moderate and then. 01:15.250 --> 01:17.950 In mode, written in. 01:18.990 --> 01:19.380 Input. 01:19.680 --> 01:21.310 So nothing new here. 01:22.140 --> 01:31.160 And then in the loop function, what I'm going to do is I'm going to read digital read button thing. 01:31.610 --> 01:34.350 I'm going to read the stage from the button. 01:34.710 --> 01:40.590 Well, and if we want to be able to monitor the difference, we need to stop because the previous one. 01:40.710 --> 01:44.550 OK, how can you know that the previous volume was high and now it's low? 01:44.790 --> 01:47.400 Well, because you stored the prejudice that you had. 01:47.640 --> 01:51.000 So we are going to store it as a global valuable byte. 01:53.080 --> 02:00.160 But in states, it's initially too low that we use bait here for the state of the button because it's 02:00.160 --> 02:01.810 just low and high. 02:02.300 --> 02:07.520 So this is maybe a little bit better, but you could also use it without any problem. 02:07.540 --> 02:09.430 OK, that's not a game changer thing. 02:09.700 --> 02:15.430 If we want the same, whether you use it or just like we did previously in some previous activities 02:15.550 --> 02:22.630 and as a quick recap byte is of value from zero to two hundred fifty five and an integer contains two 02:22.630 --> 02:29.110 bytes and with two bytes you can go from minus thirty two thousand to about thirty two thousand. 02:29.920 --> 02:34.040 So now we have our reading of the button. 02:34.060 --> 02:38.170 I'm going to save it in a new variable kinetic creating the void loop. 02:38.510 --> 02:42.010 So let's say new button state. 02:43.610 --> 02:48.650 OK, so we have the new Golden State and we have the, let's say, the Buuren state, which is also 02:48.650 --> 02:49.270 the producer. 02:49.360 --> 02:51.880 OK, so we're in the neighboring state. 02:52.250 --> 03:00.560 And then what we are going to do, we are simply going to check if the new Budden date is different 03:00.710 --> 03:02.150 than the one state. 03:04.620 --> 03:09.570 And if that is the case, we are going to see that we are going to action. 03:10.850 --> 03:16.850 And angry also just before so the other head of the mirror that I'm going to do Button St.. 03:18.360 --> 03:20.550 Is equal to New Bernstine. 03:21.960 --> 03:24.870 So every time we enter the loop, we check the balance. 03:25.580 --> 03:31.740 It's low first, then so it's low and then we press the button and the time that we press the button 03:31.920 --> 03:34.890 at this exact moment, this will give high. 03:35.040 --> 03:40.290 OK, we check the new Golden State is different from the previous button state because now it's high 03:40.290 --> 03:41.220 and this is low. 03:41.550 --> 03:48.510 So we enter this executive action and we store, of course, the brain state as the new one. 03:48.570 --> 03:55.080 OK, so the next time the value is high, we don't come back in this if again and we only come back 03:55.080 --> 03:57.610 in the if if the person is no low. 03:57.630 --> 04:01.620 So when we release the button again, what is the action we want to do? 04:01.620 --> 04:05.270 We want to print when the button was pressed aren't released. 04:05.610 --> 04:14.610 So here in this, if we know that the state of the button has just changed, so we know it's either 04:14.610 --> 04:20.250 pressed or either released now to make the difference, to go further, we can just check. 04:20.250 --> 04:26.130 So no button state is equal to new warranty, so we can just check any viable we can just check if the 04:26.130 --> 04:32.520 current state is high, which means that the bottom was priced. 04:33.790 --> 04:43.390 Cellulose print, Ellen Burton, Riced, and then we can use El's, so basically the burns steak is 04:43.390 --> 04:49.860 not high, which means that it is low because there are only two states in the label, Taylor Green 04:49.870 --> 04:50.410 Capellan. 04:53.710 --> 04:54.280 Release. 04:56.360 --> 05:02.360 Can we do this, we are going to have the exact moment when we press the button and when we release 05:02.360 --> 05:07.790 the button, so quick recap, we stole the previous state, our current state of the button here in 05:07.790 --> 05:09.860 a global Bible, then in the loop. 05:09.860 --> 05:14.540 Every time we read the new state, we compare the state with the previous one. 05:14.720 --> 05:22.010 If this is different, we know that something happened, that we, of course, stole the previous date 05:22.340 --> 05:27.970 or the next time we run the loop and then we do the action so we know something has changed. 05:28.580 --> 05:31.340 We just need to check the brain state here. 05:31.760 --> 05:34.520 If it's high, it means that we went from low to high. 05:34.520 --> 05:35.450 So we press the button. 05:35.720 --> 05:39.550 If it's low, it means we went from high to low. 05:39.560 --> 05:41.330 So the bottom was released. 05:41.750 --> 05:43.970 And now I'm going to upload that code. 05:44.870 --> 05:47.180 I'm going to save it as a button. 05:48.480 --> 05:49.140 Bounce. 05:52.140 --> 05:59.820 OK, Don, imploding and in to open the sale monitor there, and I'm going to click here on show time 05:59.820 --> 06:00.120 stamp. 06:00.180 --> 06:06.470 OK, so whenever we have something printed, we say in MONITEAU, we will also get the time stamp to 06:06.480 --> 06:11.180 help us get the exact time of the change of date. 06:11.580 --> 06:13.770 So I'm going to press the button several times. 06:14.310 --> 06:18.970 So I just press under and you can see we already have a first example of the buttons. 06:19.350 --> 06:20.360 So what did I do? 06:20.370 --> 06:28.050 I just pressed once and realized once you can see the time is really almost the same and I don't have 06:28.050 --> 06:33.840 just button pressed and button released once I have been embraced and button released twice. 06:34.350 --> 06:35.970 OK, let's make another example. 06:36.000 --> 06:36.990 So here's the mouse. 06:37.740 --> 06:38.610 I press the button. 06:38.760 --> 06:41.460 I realized I press the button. 06:41.820 --> 06:42.720 I really do it. 06:43.470 --> 06:44.160 Now let's go. 06:44.700 --> 06:47.090 Let's do a press and release quite quickly. 06:48.000 --> 06:49.140 OK, it works. 06:49.140 --> 06:50.550 We have two another one. 06:50.550 --> 06:51.870 We have to another one. 06:52.590 --> 06:53.190 Another one. 06:53.670 --> 06:54.170 Another one. 06:54.180 --> 06:58.320 Let's clear the output and let's try to get those. 07:05.020 --> 07:10.680 OK, and you can see here after several tries, so the usual behavior is that we press the button, 07:10.690 --> 07:14.770 we have been pressed, we release the button, we have button that case. 07:14.770 --> 07:22.000 You can see I press the button and then when so at this time here and then when they release the button, 07:22.510 --> 07:28.420 you can see at this exact time we also have pressed and released, which means that the Audi, you know, 07:28.420 --> 07:34.240 has detected that the button was pressed and released one more time can sometimes can be one more time, 07:34.240 --> 07:36.520 two more time, three more times, etc.. 07:37.150 --> 07:42.070 So this can be quite inconvenient because let's say you want to toggle and edit, which is something 07:42.070 --> 07:43.570 we are going to do later. 07:43.570 --> 07:44.950 Also discuss. 07:45.290 --> 07:49.760 Let's say you want to toggle the algae only when you release the push-Button. 07:50.170 --> 07:54.150 So we this normal behavior, OK, you press and you release. 07:54.160 --> 07:56.120 So you are going to toggle the energy. 07:56.140 --> 08:00.220 For example, if it was put on, you pull it off. 08:00.700 --> 08:08.380 If you are going to now put it on OK with this one, you are going to pull right off and then you press 08:08.380 --> 08:09.750 again and what happens. 08:09.760 --> 08:15.060 So the end is pulled off, you press and when you release here, the energy will be pulled on. 08:15.310 --> 08:22.970 But with these two additional dates that are monitored, the energy will return to the state both. 08:23.350 --> 08:27.090 Which means that, well, that's not what you wanted to do with your program. 08:27.670 --> 08:33.400 So this is actually the bond problem that you can clearly see with this example. 08:33.640 --> 08:38.740 And what's happening here actually will in the next lesson, you will get the complete explanation.