WEBVTT 00:00.110 --> 00:05.540 In this new activity, you will practice more with flask and the web server, and also combining this 00:05.540 --> 00:08.150 with Gpio and this time with LEDs. 00:08.150 --> 00:13.490 So your challenge is to choose which led to turn on from a web browser. 00:13.490 --> 00:19.610 So from a URL here, depending on what you write in the URL, you're going to choose to power on or 00:19.610 --> 00:21.620 to power off a certain LED. 00:21.620 --> 00:22.760 So we have three LEDs. 00:22.760 --> 00:23.900 We're going to choose which LED. 00:24.140 --> 00:27.230 And then if we want to turn it on or turn it off. 00:27.260 --> 00:27.800 All right. 00:27.800 --> 00:31.910 So you can start from what we have written previously. 00:31.910 --> 00:33.950 So here's the code that you can write. 00:33.950 --> 00:36.530 I'm going to save it as activity 11 dot pi. 00:36.530 --> 00:40.250 And I'm going to give you a few tips so you can get started. 00:40.250 --> 00:43.160 So we are going to create a new route here okay. 00:43.160 --> 00:46.100 So app dot route. 00:46.100 --> 00:48.020 And then well I'm going to write the route first. 00:48.020 --> 00:49.280 And I'm going to explain it to you. 00:49.310 --> 01:03.830 So slash LED and then slash with angle brackets int LED number and then states slash and then int state. 01:04.820 --> 01:05.180 All right. 01:05.210 --> 01:05.990 That's the new route. 01:05.990 --> 01:08.210 And then we're going to create a function. 01:08.210 --> 01:09.440 So what is this. 01:09.470 --> 01:10.610 Well we're going to start. 01:10.610 --> 01:11.870 So slash LED. 01:12.020 --> 01:16.730 And then you see we have here int LED number with angle brackets. 01:16.730 --> 01:19.580 This means that we're not going to write this in the URL. 01:19.580 --> 01:21.890 This is going to be replaced by an integer. 01:21.920 --> 01:22.310 Okay. 01:22.310 --> 01:28.580 So if you want to have dynamic URLs that you can write numbers or text or whatever inside, then you 01:28.580 --> 01:32.780 can use this angle bracket with the data type. 01:32.780 --> 01:38.450 And then the kind of the variable name that we're going to have inside our function. 01:38.450 --> 01:45.680 So here when you write the URL you will do slash LED slash you will write a number and then slash state 01:45.710 --> 01:47.390 slash another number. 01:47.420 --> 01:51.320 And actually I need to finish this with the angle brackets. 01:51.350 --> 01:51.680 All right. 01:51.710 --> 01:57.620 So for example slash LED slash zero slash state slash one. 01:57.620 --> 02:02.270 So provided that we start to count at zero zero is going to be the first LED. 02:02.420 --> 02:06.020 And then if we get the state one it means we want to turn on the LED. 02:06.020 --> 02:08.630 So we're going to turn on the first LED for the state. 02:08.660 --> 02:14.270 To keep it simple, we can say that zero means turning off, one means turning on. 02:14.300 --> 02:14.930 All right. 02:14.930 --> 02:18.080 So you have this URL that I already gave you. 02:18.080 --> 02:23.000 And then let's call this function switch LED for example. 02:23.000 --> 02:25.160 And for that one we're going to receive parameters. 02:25.160 --> 02:27.770 So the parameters is the ones that we define here. 02:27.770 --> 02:29.510 So it's going to be called LED number. 02:29.510 --> 02:31.430 And we know it's going to be an integer. 02:31.430 --> 02:36.230 And then we have state okay that's the one here okay. 02:36.260 --> 02:39.770 And then you can write of course the content of the function. 02:39.770 --> 02:42.440 So what you will do we have three LEDs. 02:42.440 --> 02:46.670 So what you can do is as we did previously in this course you can create a list. 02:46.670 --> 02:48.650 So you create a list of LEDs. 02:48.650 --> 02:50.990 Here you can initialize the first state. 02:50.990 --> 02:56.900 And then in this function you will need to well you will need to first validate that those two are correct 02:56.930 --> 02:57.800 numbers okay. 02:57.830 --> 03:03.230 Because I could give whatever number I could give 5000 here I could give minus ten here. 03:03.230 --> 03:06.710 So you want to first verify that the numbers are correct okay. 03:06.740 --> 03:14.660 So that this corresponds to an index in the list and that this is either 0 or 1 okay. 03:14.690 --> 03:20.840 So after you validate that then you can turn on or turn on the chosen LED. 03:20.930 --> 03:21.380 All right. 03:21.380 --> 03:24.290 And I will see you in the next video for the solution.