WEBVTT 00:00.080 --> 00:03.950 And we are back to our Raspberry Pi os with Tony. 00:04.070 --> 00:09.890 So make sure that you wait enough time so that the Raspberry Pi is connected again to the Wi-Fi network 00:09.890 --> 00:10.580 if needed. 00:10.580 --> 00:15.020 It can happen sometimes that the Raspberry Pi never connects well, you just remove the power cable 00:15.020 --> 00:16.130 and you put it again. 00:16.130 --> 00:19.190 But make sure that you wait at least 2 or 3 minutes before you do this. 00:19.190 --> 00:26.090 And then, well, we are connected back to the Pi, and we can use Python to detect when the button 00:26.090 --> 00:28.430 is pressed or not pressed. 00:28.430 --> 00:30.050 So how are we going to do this. 00:30.050 --> 00:33.980 Well we are going to also use the Gpio zero. 00:33.980 --> 00:38.570 So we're going to do from Gpio zero and then import. 00:38.600 --> 00:41.540 So instead of LED this time we have button. 00:41.540 --> 00:44.990 So button with only the be uppercase. 00:44.990 --> 00:49.010 Then I'm also going to import time because we're going to use it a bit later. 00:49.040 --> 00:49.490 All right. 00:49.490 --> 00:52.520 And we have everything correctly imported. 00:52.520 --> 00:54.890 Now how do we initialize the button. 00:54.890 --> 00:57.950 It's going to be very similar at what we did with the LED. 00:58.160 --> 00:59.780 You're going to create a variable here. 00:59.780 --> 01:05.330 Let's name it button for example, is equal to and you're going to use the same name here. 01:05.330 --> 01:08.570 So button with be uppercase. 01:09.320 --> 01:14.870 You open and close the parentheses and you need to give the Gpio number for that pin. 01:14.870 --> 01:23.510 And the Gpio we use to read the pushbutton value is the Gpio number 26 as you can see on the image. 01:23.510 --> 01:31.610 So what this line is going to do, it's going to initialize the Gpio 26 as an input pin for the LED 01:31.640 --> 01:32.690 was output. 01:32.720 --> 01:34.520 Here it's input. 01:34.520 --> 01:38.300 So then we can read the value from the pushbutton. 01:38.300 --> 01:41.180 And how to read the value from the pushbutton. 01:41.180 --> 01:44.090 Well we have inside button we can do button. 01:44.120 --> 01:47.090 Dot is pressed. 01:47.270 --> 01:50.960 And note here that we don't have any parentheses. 01:51.200 --> 01:53.060 It's just is pressed like that. 01:53.060 --> 02:00.320 This is going to return true if the button is pressed, and false if the button is not pressed, which 02:00.320 --> 02:02.240 is basically the two states of the. 02:02.270 --> 02:03.500 But so what to do with this? 02:03.530 --> 02:07.220 We can put it inside a variable and we can print this variable. 02:07.220 --> 02:08.840 We can also directly print it. 02:08.840 --> 02:11.540 That's what we're going to do just to test. 02:11.540 --> 02:14.540 So let's run that and let's see what we have. 02:14.840 --> 02:17.030 And well you can see we have false. 02:17.030 --> 02:19.940 So as I told you this is going to return true or false. 02:19.940 --> 02:23.300 And because the button is not pressed then we have false. 02:23.300 --> 02:26.660 And now what I will do is I will press the button okay. 02:26.690 --> 02:27.560 So the button is pressed. 02:27.560 --> 02:29.660 And at the same time I run the program. 02:30.110 --> 02:31.730 And you see now it is true. 02:31.760 --> 02:32.960 Okay, I run again. 02:32.990 --> 02:33.620 True. 02:33.650 --> 02:38.270 Then I release and then it's false again. 02:38.630 --> 02:41.330 So you can see for a push button is very easy. 02:41.330 --> 02:44.090 You just initialize the push button and then you do button. 02:44.120 --> 02:47.420 Dot is priced and you just know if the button is pressed or not. 02:47.450 --> 02:53.780 Just to improve that, let's say we want to keep reading the state of the button and print the state. 02:53.780 --> 02:58.910 For example, every one second we can do something similar as what we did with the LED. 02:58.940 --> 03:00.320 We can do a while. 03:00.350 --> 03:01.340 True. 03:01.610 --> 03:01.940 Okay. 03:01.940 --> 03:03.770 So let's create an infinite loop. 03:03.770 --> 03:07.610 And we are going to print the button in this loop. 03:07.610 --> 03:12.710 And of course we don't want to print it at an infinite speed. 03:12.710 --> 03:13.580 So it's not infinite. 03:13.610 --> 03:16.550 It's basically the the speed of the Raspberry Pi of the CPU. 03:16.550 --> 03:22.700 But we want to print it every one second, so time.sleep with one. 03:22.910 --> 03:23.060 Okay. 03:23.090 --> 03:28.040 So with this we initialize the button and then we just print its state every second. 03:28.040 --> 03:32.870 So I'm going to run this program and you can see it is false. 03:35.240 --> 03:35.750 Okay. 03:35.750 --> 03:40.460 And now so it's still false I will press you see I press on the button. 03:40.460 --> 03:42.290 It's true I release. 03:42.440 --> 03:49.610 It's false I press again, it is true I release it's false etc. etc.. 03:49.970 --> 03:50.420 Great. 03:50.420 --> 03:55.700 So in this section you have seen how to control an LED and a push button with Python. 03:55.700 --> 04:01.310 We are going to practice more with this and see how to combine a push button, an LED and then even 04:01.310 --> 04:02.660 more components.