WEBVTT 00:00.080 --> 00:06.530 This is the solution of the activity number five, where you have to send a message from the Arduino 00:06.530 --> 00:07.360 to the Raspberry Pi. 00:07.370 --> 00:13.790 When you press on the push button and then receive a color for one of the LEDs. 00:13.790 --> 00:18.950 So basically one of the color of the RGB and then change that color from the Arduino. 00:19.070 --> 00:25.850 So once again, let's start to do the Arduino code and then we're going to debug the Arduino code with 00:25.850 --> 00:30.620 the sign monitor, and then we're going to write the Python program on the Raspberry Pi. 00:30.620 --> 00:34.370 So let's initialize I'm going to remove this. 00:34.370 --> 00:36.920 Let's initialize the hardware components. 00:36.920 --> 00:43.340 So define button pin, which is pin number seven, and then define. 00:44.110 --> 00:49.420 RGB red pin, which is 11. 00:50.300 --> 00:53.390 And let's do the same for the green and the blue. 00:54.960 --> 00:55.650 Green. 00:57.470 --> 00:59.510 Blue and we have ten. 00:59.780 --> 01:01.760 And we have nine. 01:02.300 --> 01:02.780 Okay. 01:02.780 --> 01:14.750 In the void setup, what we do is spin mode with button pin input. 01:16.330 --> 01:17.650 And then pinmode. 01:18.790 --> 01:23.020 For the red pin to output. 01:23.920 --> 01:24.520 Okay. 01:24.520 --> 01:28.750 And then the same for the green. 01:28.780 --> 01:30.160 The same for. 01:31.160 --> 01:31.720 W. 01:33.320 --> 01:41.480 So I go quite fast with that because we've already done that multiple times and then I'm going to open 01:42.110 --> 01:42.950 style communication. 01:42.950 --> 01:47.510 So style dot begin with, let's keep the same ball rate. 01:49.270 --> 01:50.380 And while. 01:53.020 --> 01:55.600 So let's wait. 01:56.050 --> 01:56.650 All right. 01:57.490 --> 01:59.060 Now, what do we do? 01:59.080 --> 02:02.170 I'm going to also remove that. 02:03.260 --> 02:07.910 So we have two things to do which are, well, actually completely independent. 02:07.940 --> 02:15.770 First, we need to read the purge button, check when it is pressed and send a message to the sale. 02:15.980 --> 02:21.090 The second action is to receive something from the sale and check what command we have. 02:21.110 --> 02:26.110 If it's right green or blue and then apply the command to the Led. 02:26.150 --> 02:31.460 So while there is no particular order to do that, you can debug both independently. 02:31.460 --> 02:34.040 But let's start with let's say the push button. 02:34.070 --> 02:34.610 Okay. 02:34.850 --> 02:38.420 So I'm going to do the Debounce code for the push button once more. 02:38.630 --> 02:52.310 Unsigned long last time button changed, let's say millis and then unsigned long button. 02:53.780 --> 02:54.920 Let's say Debounce. 02:56.330 --> 03:07.790 DeLay is let's put 50 milliseconds another time and then so unsigned long time now is equal to millis. 03:07.790 --> 03:09.350 So we get the current time. 03:10.070 --> 03:16.160 We check if time now minus last time the button has changed. 03:16.610 --> 03:20.210 If this is greater or equal than the debounce delay. 03:21.530 --> 03:34.370 Then we can enter this if and what we can do is do white button state is equal to digital read from 03:34.370 --> 03:36.110 button pin. 03:36.320 --> 03:38.030 Then we will need to. 03:38.510 --> 03:42.860 So we will need to compare the button state with the previous button state. 03:42.860 --> 03:49.160 So I'm going to add here white previous button state. 03:50.000 --> 04:01.430 And just after we do the PIN modes I'm going to do previous button state is equal to digitalwrite from 04:01.430 --> 04:02.570 button pin. 04:03.020 --> 04:11.220 So we have the first state here at the beginning and then we are going to compare Button State. 04:11.240 --> 04:17.990 So if this is different than the previous one, then we need to do two things. 04:17.990 --> 04:23.690 We need to update the last time the button has changed to time now. 04:24.000 --> 04:24.380 Okay. 04:24.380 --> 04:27.560 So then the debounce is going to happen another time. 04:27.560 --> 04:35.630 We're going to do the previous button state is equal to button state. 04:36.640 --> 04:46.030 And then we can check if Button State is equal to hi here because we have a pull down resistor. 04:46.270 --> 04:51.400 Then the button button is pressed. 04:52.130 --> 04:52.580 Okay. 04:52.580 --> 04:56.600 And let's do self dot print ln. 04:57.960 --> 04:58.440 And. 04:58.440 --> 05:00.430 Well, what do we send here? 05:00.450 --> 05:01.440 I'm not going to do. 05:01.440 --> 05:02.530 Button is pressed. 05:02.550 --> 05:02.940 Okay. 05:02.940 --> 05:03.990 This is not a log. 05:03.990 --> 05:08.280 This is a communication from the Arduino to the Raspberry Pi. 05:08.430 --> 05:18.030 So let's say we are going to send button pressed like this and here we're going to receive button pressed. 05:18.060 --> 05:18.630 Okay. 05:19.380 --> 05:23.520 So very important to agree on what you send and what you receive. 05:23.640 --> 05:29.270 And well, I'm first going to just check if that code is working. 05:29.280 --> 05:32.760 So activity five. 05:33.890 --> 05:34.670 Compiling. 05:34.700 --> 05:35.690 Uploading. 05:36.680 --> 05:40.960 Okay, let's open the serial monitor and let's press on the push button. 05:40.970 --> 05:42.920 Button pressed another time. 05:42.920 --> 05:45.200 Button pressed button pressed. 05:45.230 --> 05:47.060 It is working. 05:47.060 --> 05:47.660 Great. 05:47.660 --> 05:51.260 So now let's do the code for the RGB led. 05:51.650 --> 05:54.140 So we have this already. 05:54.260 --> 05:57.890 Well, we have the initialization, which is okay. 05:57.920 --> 06:00.890 Now let's do so here in the void loop. 06:00.890 --> 06:03.650 Make sure you don't make a mistake, okay? 06:03.650 --> 06:07.070 And that you don't put the code in the wrong block of code. 06:07.070 --> 06:09.110 So that's going to be here. 06:09.980 --> 06:11.180 So if. 06:13.860 --> 06:15.700 Dot available. 06:16.800 --> 06:18.540 Greater than zero. 06:18.540 --> 06:20.850 So that doesn't change really. 06:22.410 --> 06:22.980 Then. 06:22.980 --> 06:25.110 So if we have received something. 06:26.200 --> 06:27.400 We're going to do string. 06:30.120 --> 06:33.700 Simply command is equal to self dot. 06:33.720 --> 06:34.680 And guess what? 06:34.710 --> 06:41.820 Read string until backslash n with one single quote. 06:43.200 --> 06:47.790 And then we do if and that's where we are going to check what command we have received. 06:47.790 --> 06:51.110 Because here we can receive three different command. 06:51.120 --> 07:01.020 So if command dot starts with so the command can start with, for example, read like this, then we're 07:01.020 --> 07:11.580 going to process the read command and then else if cmd dot starts with we have green. 07:13.750 --> 07:14.350 Okay. 07:15.340 --> 07:29.530 Else if cmd dot start with blue and then let's do another else like I did before. 07:30.310 --> 07:31.930 Nothing for now. 07:32.560 --> 07:37.840 Or maybe what we could do if we receive an error is just to, for example, power off completely the 07:37.870 --> 07:38.640 RGB entity. 07:38.710 --> 07:39.880 Okay, It's up to you. 07:40.920 --> 07:50.370 So if we receive the red color, what we can do with the command is first to do cmd dot remove and then 07:50.370 --> 07:52.050 zero for. 07:53.310 --> 07:54.420 Okay, we'll remove. 07:54.540 --> 07:56.950 So zero, one, two, three, four. 07:56.970 --> 08:00.900 We'll remove all of that and we are left with the number. 08:00.900 --> 08:02.490 But the number is actually a string. 08:02.490 --> 08:12.840 So we do for example, int red is equal to C and D dot to int like this. 08:12.840 --> 08:26.010 And then analog, right with RGB red pin and with the red number that we got from the command and what 08:26.010 --> 08:26.370 we can do. 08:26.370 --> 08:30.300 The same with every other command. 08:30.300 --> 08:32.640 So cmd dot remove. 08:32.670 --> 08:38.070 But here we don't do zero four because if we do zero four we're going to remove one, two, three, 08:38.070 --> 08:43.560 four and we are going to be left with n colon and the number. 08:43.560 --> 08:47.940 So we do zero one, two, three, four, five, six. 08:47.970 --> 08:48.480 Okay. 08:48.480 --> 08:54.880 So as you can see each command, you will need to process it independently and make sure that it's working. 08:55.330 --> 08:59.590 INT green is equal to cmd dot to INT. 08:59.620 --> 09:04.840 This doesn't change in analog, so let's use analog write the same. 09:04.840 --> 09:05.470 But. 09:06.890 --> 09:07.820 We've. 09:09.580 --> 09:11.440 Green and. 09:12.970 --> 09:13.510 Green. 09:15.520 --> 09:17.020 Okay. 09:17.170 --> 09:18.640 And then for the blue. 09:20.300 --> 09:24.860 We do cmd dot remove and how many do we need to remove? 09:24.890 --> 09:27.050 One, 2345. 09:27.050 --> 09:35.330 So zero five and then int blue is equal to cmd dot to int. 09:35.330 --> 09:42.740 And let's do analog right with the blue pin and the blue color. 09:43.950 --> 09:44.250 Okay. 09:44.250 --> 09:49.590 And now we can try this code actually on the Arduino to check if it's correctly working and well, if 09:49.590 --> 09:55.680 you want an additional debug step because maybe well, let's say you want to send the right or the green 09:55.680 --> 09:57.270 or the blue command and it doesn't work. 09:57.300 --> 10:00.300 You don't necessarily know why it doesn't work. 10:00.300 --> 10:08.220 So what you can do, for example, let's say here Serial.println, for example, red, so we can just 10:08.220 --> 10:11.490 use this when we debug the Arduino with the serial monitor. 10:11.490 --> 10:13.230 And then of course that's very important. 10:13.260 --> 10:18.450 Don't forget to remove any log that you have put first for the Arduino side. 10:18.450 --> 10:21.210 So let's upload the code to the Arduino. 10:23.360 --> 10:27.950 Let's open the serial monitor so we still have the push button. 10:28.190 --> 10:30.710 That will show button pressed. 10:30.710 --> 10:34.490 And then let's do red colon 200. 10:34.820 --> 10:38.060 You can see it is correctly working and we have 200. 10:38.090 --> 10:40.010 Okay, let's do green. 10:41.060 --> 10:42.170 100. 10:42.590 --> 10:42.920 Okay. 10:42.920 --> 10:46.850 We have a different color in blue and 50. 10:47.510 --> 10:48.610 Let's do blue. 10:48.620 --> 10:49.970 Actually, 200. 10:50.810 --> 10:51.260 Okay. 10:51.260 --> 10:52.550 And maybe red. 10:52.730 --> 10:53.690 Zero. 10:54.020 --> 10:54.490 Right. 10:54.560 --> 10:56.510 And green. 10:57.350 --> 10:58.160 Zero. 10:59.240 --> 11:01.070 Blue, 200. 11:01.100 --> 11:03.260 Well, there is something wrong with blue. 11:05.170 --> 11:11.410 And well, actually, I have checked that I have used I don't know why, but 19 for the blueprint. 11:11.410 --> 11:13.000 So of course that doesn't work. 11:13.000 --> 11:14.830 So you can see here that didn't work. 11:14.830 --> 11:16.540 We didn't see the command blue change. 11:16.540 --> 11:20.650 And then it helped us to actually see that we have an error in our code. 11:20.650 --> 11:23.350 So now let's run that again. 11:25.780 --> 11:28.420 I'm going to open the side monitor again and just. 11:29.520 --> 11:36.360 Test blue with two 100 and well, the blue is working great. 11:36.630 --> 11:39.030 So now I can just close that. 11:39.030 --> 11:41.630 I could also do a print with the blue. 11:41.640 --> 11:41.900 Okay. 11:41.940 --> 11:45.930 To make sure that we receive from sale and I'm going to remove this is very important. 11:45.930 --> 11:51.930 Any log that I have put which have nothing to do with the cell communication with the Raspberry Pi. 11:52.290 --> 11:52.650 Okay. 11:52.650 --> 11:56.040 So now the Arduino code is working. 11:56.040 --> 12:00.900 I'm going to upload also the new code, of course, without the dot print. 12:00.950 --> 12:04.830 Ellen Okay, The Arduino side is working. 12:04.920 --> 12:07.890 Let's go to the Raspberry Pi side. 12:08.460 --> 12:15.420 So first of all, we need to initialize serial and everything, but I'm going to use the code from the 12:15.420 --> 12:16.770 previous activity. 12:17.190 --> 12:21.150 So select everything so you can do this by yourself. 12:21.150 --> 12:25.320 But I'm going to do this so it goes a bit faster. 12:25.320 --> 12:30.370 And anyway, we have already done that multiple times. 12:30.370 --> 12:31.270 So what? 12:31.270 --> 12:33.310 I'm going to remove that also. 12:34.830 --> 12:44.190 You adjust the input initialization and then the infinite loop with the time.sleep very important. 12:44.280 --> 12:51.900 And I'm going to so I'm going to import random here and let's remove that. 12:52.830 --> 12:56.840 Okay, so what do we do on the Raspberry Pi? 12:56.850 --> 13:03.420 Well, we don't send anything without receiving anything, so we first need to check that we have received 13:03.420 --> 13:04.080 something. 13:04.080 --> 13:14.460 So in the while true if say, dot in waiting is greater than zero again without parentheses, then we 13:14.460 --> 13:16.440 do, let's say message. 13:18.040 --> 13:19.120 Is equal to. 13:19.540 --> 13:22.660 And from this age we could also do MSG, for example. 13:22.900 --> 13:25.330 That's the same as using CMD for command. 13:25.360 --> 13:29.290 Okay, that's pretty explicit and that's something you're going to use very often. 13:29.290 --> 13:31.630 So that's not a big deal. 13:31.870 --> 13:35.680 And so set dot readline dot. 13:37.530 --> 13:38.430 Decode. 13:39.560 --> 13:41.360 UTF eight. 13:42.760 --> 13:44.310 Dot s trick. 13:46.390 --> 13:46.660 Okay. 13:46.660 --> 13:55.360 And then what we do is we check if message is equal to is equal to what is equal to button pressed. 13:55.720 --> 13:56.260 Okay. 13:56.590 --> 13:57.940 We send button pressed. 13:57.940 --> 14:00.130 We check if we receive button pressed. 14:00.160 --> 14:05.620 If we have received button pressed, then we are going to process the action. 14:05.620 --> 14:08.890 And what is the action is to choose a random color. 14:09.160 --> 14:13.180 So right green and blue and then the random number for that color. 14:13.690 --> 14:25.780 Okay, so let's do D is equal to random dot rand int with zero and to. 14:27.780 --> 14:39.630 And then the number is equal to random dot rand, int from 0 to 255. 14:40.500 --> 14:40.770 Okay. 14:40.770 --> 14:44.100 And then we're going to construct the string that we're going to send. 14:44.130 --> 14:44.640 Okay. 14:44.940 --> 14:50.040 So the command and so let's start with CMD is equal to an empty string. 14:50.040 --> 15:02.400 And then if ID is equal to one, we do cmd plus red. 15:03.440 --> 15:04.720 And then let's do L. 15:04.790 --> 15:09.110 If Z is equal to two, we do cmd. 15:10.880 --> 15:13.130 Less green. 15:14.640 --> 15:21.210 And then let's do ls cmd plus blue. 15:22.110 --> 15:29.460 So we have the first part of the command and then we add So cmd plus. 15:30.550 --> 15:33.280 Number, but actually as a string. 15:33.280 --> 15:39.370 So we cast the number as a string and then cmd plus. 15:40.260 --> 15:41.460 Backslash. 15:42.060 --> 15:42.600 N. 15:43.800 --> 15:50.580 Okay, so we start from an empty string, then we construct it with first the command name red, green 15:50.580 --> 15:58.050 and blue, and then the number we want to read that we're going to get here and then backslash n for 15:58.050 --> 16:00.120 the read string until with the backslash. 16:00.120 --> 16:01.380 N Okay. 16:01.380 --> 16:05.190 And then we can do set dot write. 16:06.460 --> 16:09.670 CMD dot encode UTF. 16:10.800 --> 16:13.410 Eight like this. 16:13.980 --> 16:17.310 And let's see if that works. 16:17.340 --> 16:21.760 Maybe we can add some prints here because it's easier to debug on Python. 16:21.780 --> 16:22.950 We can add some prints. 16:22.950 --> 16:25.350 So let's say here print. 16:27.030 --> 16:28.740 Button has been pressed. 16:31.010 --> 16:31.310 Okay. 16:31.310 --> 16:40.490 And then maybe print, send, command plus command. 16:41.240 --> 16:44.450 So we're gonna make sure that we send the correct command. 16:44.480 --> 16:44.930 Okay. 16:44.930 --> 16:47.170 Because we know that the Arduino side is working. 16:47.180 --> 16:53.540 So if we send something from the Raspberry Pi to the Arduino, and if it doesn't work, well, we probably 16:53.540 --> 16:56.630 know that this is because we sent the wrong thing. 16:56.630 --> 17:00.380 So if we just print the thing, it's easier to debug. 17:00.530 --> 17:06.170 Let's save this as activity five. 17:07.790 --> 17:12.020 And so the Arduino is already uploaded. 17:12.020 --> 17:16.220 Let's run it on the Raspberry Pi. 17:18.270 --> 17:18.600 Okay. 17:18.600 --> 17:19.770 You can see cereal. 17:19.800 --> 17:20.130 Okay. 17:20.280 --> 17:20.850 And now? 17:20.850 --> 17:23.220 Well, what I need to do is I need to press on the push button and. 17:23.220 --> 17:24.000 Let's see. 17:25.330 --> 17:30.520 Okay, we have an error and well, actually okay. 17:30.550 --> 17:34.890 The module random has no attribute rand int simply because. 17:34.900 --> 17:38.770 Well I have to use a lowercase here. 17:39.580 --> 17:39.900 Okay. 17:39.910 --> 17:43.540 I have used uppercase but it is a lowercase. 17:43.540 --> 17:44.820 I made a mistake. 17:44.830 --> 17:46.630 So now let's run again. 17:50.330 --> 17:50.910 Sale. 17:50.990 --> 17:56.810 Okay, let's press on the push button and you can see button has been pressed. 17:56.810 --> 17:59.960 Send command red 125. 17:59.990 --> 18:00.980 I press again. 18:01.920 --> 18:05.690 Send comments or write again here. 18:05.700 --> 18:07.100 Write again with 30. 18:07.110 --> 18:10.470 And here you can see Blue 237. 18:11.370 --> 18:11.880 Green. 18:11.880 --> 18:12.840 36. 18:13.170 --> 18:14.460 Green 200. 18:14.550 --> 18:19.440 Okay, so every time we change one color, 174 for blue. 18:19.470 --> 18:20.280 ET cetera. 18:20.310 --> 18:21.110 ET cetera. 18:21.120 --> 18:23.850 So now I press control C okay. 18:23.850 --> 18:26.190 And you can see adding some. 18:27.890 --> 18:34.700 A print here on the Python side is very, very useful to see what you send and then you can check that 18:34.700 --> 18:41.030 it's correctly doing what you want to do on the Arduino side and that's the end of this activity.