WEBVTT 00:00.080 --> 00:02.090 This is the solution of the activity. 00:02.090 --> 00:08.690 Two, where you have to send some random temperature from the Arduino process that in the Raspberry 00:08.690 --> 00:13.210 Pi so that you can choose to power on or power off the Led. 00:13.310 --> 00:17.840 If, for example, you can power on the Led if the temperature is too low. 00:17.840 --> 00:19.790 So let's start with the Arduino side. 00:19.820 --> 00:21.110 Once again. 00:21.650 --> 00:23.240 I'm going to remove that. 00:23.870 --> 00:27.230 So I already have this. 00:27.260 --> 00:27.890 Okay. 00:28.040 --> 00:29.880 Unsigned long last time. 00:29.900 --> 00:30.350 Action. 00:30.560 --> 00:35.330 I'm going to remove this and just rename it last time. 00:35.810 --> 00:39.440 Let's say temperature sent. 00:39.500 --> 00:40.050 Okay. 00:40.070 --> 00:41.840 Which makes more sense. 00:41.840 --> 00:45.650 And then I'm going to do temperature. 00:46.220 --> 00:49.340 Send delay. 00:51.440 --> 00:53.120 And let's keep one second. 00:53.150 --> 00:53.690 Okay. 00:54.080 --> 00:55.520 So now, void loop. 00:55.550 --> 00:56.390 Unsigned long. 00:56.390 --> 01:04.190 We get the time now with Millis and we check if the time now minus the last time temperature sent is 01:04.190 --> 01:06.530 greater than temperature. 01:06.560 --> 01:07.940 Send delay. 01:08.300 --> 01:14.360 And in that case, we don't forget to update the last time temperature sent to the time now. 01:14.360 --> 01:20.450 So basically, this here, this code here is going to be called every one second. 01:20.450 --> 01:23.640 And we don't block the void loop with the delay. 01:23.730 --> 01:33.670 So to get the temperature I'm going to do int temperature is equal to and let's use the random 5 to 01:33.670 --> 01:34.230 25. 01:34.260 --> 01:34.770 Okay. 01:35.810 --> 01:37.100 And itrillionemove that. 01:38.910 --> 01:42.660 And what we're going to do now is we're going to send this to the cell. 01:42.960 --> 01:48.030 So I'm going to do in the void setup Serial.begin. 01:49.340 --> 01:51.350 So same code. 01:52.210 --> 01:57.170 And then while cell like this. 01:59.060 --> 02:05.240 And here I can do serial dot println with temperature. 02:08.100 --> 02:10.590 All right, let's actually test this code. 02:10.710 --> 02:17.910 So I'm going to do a upload activity to. 02:21.620 --> 02:24.790 Don't uploading and how to test this code. 02:24.790 --> 02:27.940 I just open the soil monitor and let's see what we receive. 02:27.970 --> 02:34.990 12, 12, 14, 18, 23, 15, 17, nine. 02:34.990 --> 02:37.210 So you can see it's correctly working. 02:37.210 --> 02:42.400 We receive a random number between 5 and 25 every second. 02:42.430 --> 02:42.910 Okay. 02:42.910 --> 02:47.380 So the first part of the Arduino code is done now in parallel. 02:47.380 --> 02:53.320 So I say in parallel because we're going to do the two actions, one after the other, but very fast. 02:53.320 --> 02:56.080 So it's just like we are doing them in parallel. 02:56.080 --> 03:01.090 I'm going to do if soil dot available. 03:03.850 --> 03:05.410 Is greater than zero. 03:07.570 --> 03:13.540 So if we have received some data, what we're going to do is the same thing we did in the previous activity. 03:13.570 --> 03:15.340 So I'm going to do that very fast. 03:15.460 --> 03:26.590 String command is equal to self dot read string until backslash n with one single quote. 03:26.590 --> 03:38.230 And then if command is equal to n, we are going to power on the else if command is equal to. 03:39.210 --> 03:50.100 Off, we power off the lid and then else we can process the other command and for example, print an 03:50.100 --> 03:51.370 error or something like that. 03:51.390 --> 03:51.900 Okay. 03:51.900 --> 03:56.610 Now for the Led, I will need to initialize Led. 03:56.610 --> 04:01.560 So let's create a define Led pin 13 here. 04:01.560 --> 04:02.700 Let's do so. 04:02.700 --> 04:05.240 I can do the PIN mode before or after serial. 04:05.250 --> 04:06.780 It doesn't really matter here. 04:06.870 --> 04:13.680 PIN mode led pin with output. 04:14.940 --> 04:28.740 And here I do digital write led pin with high because we power on the Led and digital write led pin 04:28.950 --> 04:31.050 low because we power off the Led. 04:31.320 --> 04:31.590 Okay. 04:31.590 --> 04:36.090 So we have this action and this action running separately. 04:36.090 --> 04:43.920 As you can see here, we send data with sale dot print ln and we receive data with sale dot read string 04:43.920 --> 04:46.800 until but the two are not directly linked. 04:46.800 --> 04:47.100 Okay? 04:47.100 --> 04:50.040 We don't just send data when we receive data. 04:50.070 --> 04:50.490 Okay. 04:50.490 --> 04:53.100 We have separated the two actions. 04:53.190 --> 04:55.470 Let's upload this code to the Arduino. 04:58.300 --> 04:58.540 Okay. 04:58.540 --> 05:01.810 And what you can do, for example, is you can just open the monitor. 05:01.840 --> 05:04.420 You're going to see that you receive some numbers. 05:04.540 --> 05:05.110 Okay. 05:05.110 --> 05:11.870 And let's just give on and let's see that the Led is powered on. 05:11.890 --> 05:12.940 Okay, That's working. 05:14.360 --> 05:22.070 And as you may see, the random here is maybe not that random because we have the same data as before. 05:22.070 --> 05:26.060 So you could make it more random, but I'm not going to spend time on this. 05:26.060 --> 05:26.300 Okay. 05:26.300 --> 05:28.400 That's outside of the scope of this course. 05:28.400 --> 05:31.070 If you want, you can search more about this by yourself. 05:31.280 --> 05:31.700 All right. 05:31.700 --> 05:33.590 So the Arduino code is done. 05:34.040 --> 05:36.440 Let's go to the Raspberry Pi side. 05:36.770 --> 05:36.980 Okay. 05:36.980 --> 05:39.830 So we read from Serial and we receive a number. 05:39.830 --> 05:50.120 So if we want to read from Serial, what we are going to do is to do if, say, dot in waiting is greater 05:50.120 --> 05:51.110 than zero. 05:51.110 --> 05:53.210 And here no parenthesis. 05:53.240 --> 05:59.570 Okay, you have parentheses here with dot available, no parentheses here. 06:00.350 --> 06:04.880 So if we have received something, then we read that thing. 06:04.880 --> 06:13.490 Okay, so let's say temperature is equal to C dot read line. 06:14.500 --> 06:19.240 Dot decode with UTF. 06:20.490 --> 06:24.250 Eight and strip. 06:26.880 --> 06:28.590 Okay, So the same thing we did before. 06:28.590 --> 06:31.620 So we read the line, we decode it because it's bytes. 06:31.620 --> 06:38.790 So we decode it into a string and we remove any other special character we have at the end. 06:38.790 --> 06:45.330 And what I'm going to do is I'm also going to cast this into an integer, okay? 06:45.330 --> 06:48.810 Because what we want to process the temperature as an integer. 06:48.810 --> 06:51.180 So I'm going to cast it as an integer. 06:51.240 --> 07:01.170 And to do that I simply do INT and I put everything in the parentheses and now if temperature is lower, 07:01.170 --> 07:03.150 strictly lower than 15, let's say. 07:04.230 --> 07:06.540 Then we are going to power on the Led. 07:07.290 --> 07:09.210 So let's put a comment here. 07:09.240 --> 07:12.540 Power on Led and then else. 07:12.570 --> 07:20.490 So basically, if the temperature is greater or equal than 50, we are going to power off. 07:21.330 --> 07:23.400 So let's actually do a print. 07:23.650 --> 07:24.360 Print. 07:25.930 --> 07:31.060 Temperature lower than 15. 07:32.710 --> 07:33.640 Lead on. 07:34.690 --> 07:35.770 And here. 07:37.350 --> 07:38.130 Print. 07:39.510 --> 07:49.530 Temperature lower or greater actually than 15 of. 07:50.790 --> 07:53.730 And then, of course, we send the command. 07:53.730 --> 07:56.220 So the command is still on and off. 07:56.220 --> 07:56.700 Okay. 07:56.880 --> 08:09.000 So say dot write with on and backslash n dot encode with UTF. 08:09.740 --> 08:12.470 Eight like this. 08:12.710 --> 08:16.250 And then I'm going to copy this here in the else. 08:16.250 --> 08:19.340 And instead of on, we send off. 08:19.670 --> 08:21.530 So as you can see the structure here. 08:21.530 --> 08:24.890 So we continue with our while true. 08:24.890 --> 08:29.780 So the infinite loop, if we have received some data, we read that data. 08:29.870 --> 08:31.630 So we cast it as an int. 08:31.640 --> 08:37.290 So here it's very important, as you see here, that we also have defined a protocol. 08:37.310 --> 08:43.090 The protocol is simply that here we send the number, here we receive a number, okay? 08:43.100 --> 08:45.800 And here we send on and off. 08:45.800 --> 08:48.080 Here we receive on and off. 08:48.080 --> 08:48.590 Okay. 08:48.590 --> 08:54.020 So on both sides, we know what we receive and what we send. 08:54.410 --> 08:59.240 Okay, let's now try this code so it's already uploaded on the Arduino. 08:59.270 --> 09:02.660 I'm going to run that on the Raspberry Pi. 09:05.070 --> 09:09.810 So activity 2.py. 09:09.840 --> 09:11.670 It's going to be added automatically. 09:13.910 --> 09:15.530 And let's see what we get. 09:16.700 --> 09:16.970 Okay. 09:16.970 --> 09:24.650 You can see that when the temperature is lower than 15, we have the Led on and when the temperature 09:24.650 --> 09:27.530 is greater than 15, we have the Led off. 09:29.240 --> 09:29.690 All right. 09:29.690 --> 09:32.030 And that's the end of this activity.