WEBVTT 00:00.050 --> 00:00.350 All right. 00:00.350 --> 00:06.500 This is the solution of the previous activity where you need to make the servo sweep from the Raspberry 00:06.500 --> 00:11.390 Pi and then you're going to change the speed when you press on the push button on the Arduino. 00:11.390 --> 00:12.110 And so. 00:12.110 --> 00:15.290 Well, once again, let's start with the Arduino side. 00:15.290 --> 00:23.330 So I'm first going to do the button press code and actually let's open the previous activity, which 00:23.330 --> 00:24.350 was five. 00:26.520 --> 00:34.440 So I am not going to write the complete code for the push button because we just did it in the activity 00:34.440 --> 00:36.330 and in one of the previous lessons. 00:36.330 --> 00:37.080 So. 00:37.380 --> 00:40.440 Well, if you want more explanation, please go back. 00:42.040 --> 00:44.770 In a previous video to get the explanations of that. 00:44.770 --> 00:46.840 I'm just going to hit copy. 00:48.730 --> 00:51.340 The code that we already wrote before. 00:51.370 --> 00:54.140 Okay, so that doesn't come from nowhere. 00:54.160 --> 00:56.650 That comes from something we have already done. 00:57.730 --> 00:58.240 Okay. 00:58.240 --> 01:03.310 And I'm going to also initialize the serial, as always. 01:03.310 --> 01:07.300 And then well, you see, that's the part of the code I want to copy here because. 01:07.300 --> 01:10.870 Well, we're not going to write that again. 01:12.040 --> 01:12.540 Okay. 01:12.670 --> 01:13.720 And that's it. 01:13.740 --> 01:14.920 I'm going to close that. 01:14.920 --> 01:22.090 So in our code for now, we have so the define for the button, some variables we initialize the button 01:22.090 --> 01:23.320 and the previous state. 01:24.360 --> 01:25.620 And then in the void loop. 01:26.430 --> 01:29.910 So make sure you have the correct blocks of code here. 01:29.910 --> 01:33.990 So well in the void loop, we read the current time, we check the duration. 01:33.990 --> 01:36.510 Since last time the button has changed. 01:36.540 --> 01:42.690 If this is greater than the debounce delay, then we read the push button, we compare it, we update 01:42.690 --> 01:47.880 the variables and if it's high, the button has been pressed and we send button pressed. 01:47.880 --> 01:53.040 So just to be sure, let's plot that to the Arduino activity. 01:54.480 --> 01:55.260 Six. 01:59.150 --> 02:00.350 Down uploading. 02:00.350 --> 02:01.780 Let's open the monitor. 02:01.970 --> 02:03.440 Press on the push button. 02:03.650 --> 02:05.300 Button pressed. 02:05.450 --> 02:07.300 If I press multiple times. 02:07.310 --> 02:08.300 Okay, great. 02:08.750 --> 02:11.960 Now let's do the code for the servo. 02:12.380 --> 02:15.110 So I'm going to initialize the servo. 02:15.110 --> 02:20.450 So define servo pin 12. 02:20.630 --> 02:22.730 Let's include 02:25.970 --> 02:29.090 the servo dot h library. 02:29.390 --> 02:32.930 And let's create so we can create it before that or after. 02:32.930 --> 02:33.950 It doesn't matter. 02:34.040 --> 02:34.940 Servo. 02:35.210 --> 02:36.140 Servo. 02:36.620 --> 02:37.790 Semicolon. 02:39.080 --> 02:46.310 And here let's do several dot attach servo pin. 02:47.330 --> 02:47.600 Okay. 02:47.600 --> 02:50.510 The servo is initialized and now in the void loop. 02:50.510 --> 02:53.630 After we have read or before, it doesn't matter again. 02:53.630 --> 03:06.950 So after we have read from the push button, let's do if serial dot available greater than zero and 03:06.950 --> 03:08.210 then let's check. 03:08.300 --> 03:18.200 So what command we're going to receive, let's do string cmd is equal to read string until backslash 03:18.200 --> 03:23.090 n and then if command dot. 03:23.090 --> 03:25.340 So what do we want to receive? 03:25.370 --> 03:28.490 We want to receive the servo command with a number. 03:28.490 --> 03:33.650 So let's say that we're going to receive something that starts with. 03:36.510 --> 03:40.260 Several colon like this. 03:41.710 --> 03:44.410 And then the angle we want. 03:44.710 --> 03:47.710 And so we can do command dot remove. 03:48.590 --> 03:48.810 Okay. 03:48.880 --> 03:53.470 We start at zero one, two, three, four, five, six. 03:53.470 --> 03:58.360 So zero six we are left with the number. 03:58.360 --> 04:04.860 So int angle is equal to cmd dot two int. 04:05.910 --> 04:07.170 What we could do also. 04:07.170 --> 04:08.400 Now we're not going to do it. 04:08.400 --> 04:14.370 But what we could do as an improvement is to check that the angle is actually between 0 and 180. 04:14.400 --> 04:14.630 Okay. 04:14.640 --> 04:22.830 So that we don't receive values that are negative, for example, or values that are greater than 180. 04:23.310 --> 04:29.850 And then we do servo dot right angle and that's pretty much it. 04:29.940 --> 04:37.320 We have the code to send the button pressed message and we have the code to receive and execute the 04:37.320 --> 04:38.970 servo command. 04:39.810 --> 04:41.270 Okay, let's check. 04:41.280 --> 04:46.830 Yes, I'm going to upload the code and test this code. 04:48.240 --> 04:55.090 And well, actually it's better if I do serial dot read string until because this is part of the serial 04:55.140 --> 04:58.920 library, not just a random function like this. 04:59.100 --> 05:00.240 Let's upload. 05:02.490 --> 05:05.210 Uploading, download, uploading. 05:05.910 --> 05:09.810 Let's open the serial monitor and let's see what we have on the circuit. 05:09.810 --> 05:17.190 So first, well, if you have like like me, if you have disconnected the servo pin here on pin 12, 05:17.220 --> 05:18.290 put it back. 05:18.300 --> 05:18.900 Okay? 05:18.990 --> 05:21.180 Because if not, that's not going to work. 05:21.180 --> 05:24.900 So if I press on the push button, it's still working, button pressed. 05:24.900 --> 05:30.810 And then I'm going to do several, for example, zero and let's press enter. 05:31.230 --> 05:37.050 Okay, it goes to zero and then servo with 153. 05:37.080 --> 05:40.680 For example, it goes to 153. 05:40.710 --> 05:42.540 That's correctly working. 05:42.660 --> 05:48.930 So I'm going to close that and where I think we are done with the Arduino code. 05:48.930 --> 05:52.710 Let's now switch to the Raspberry Pi code so you could see that on the Arduino. 05:52.710 --> 05:54.930 Well, we didn't have many things to do. 05:54.930 --> 05:55.470 Okay. 05:56.740 --> 06:00.610 We just send something here, we just receive something here. 06:00.610 --> 06:03.390 There is no link between the two actions. 06:03.400 --> 06:03.840 Okay? 06:03.850 --> 06:07.870 The link between the two actions is going to be on the python side. 06:08.410 --> 06:11.080 So let's remove. 06:11.080 --> 06:12.580 Well, let's remove all of that. 06:12.580 --> 06:12.820 Okay. 06:12.820 --> 06:14.740 We know what to do. 06:14.980 --> 06:17.380 Let's start from a blank page. 06:17.770 --> 06:18.910 Well, a blank page. 06:18.910 --> 06:20.830 No, because I'm going to use, of course, the structure. 06:20.830 --> 06:28.300 So let's go to any of the previous activity and let's just paste the structure, remove what we don't 06:28.300 --> 06:28.930 need. 06:30.460 --> 06:31.480 Like this. 06:32.560 --> 06:36.010 Okay, That's the structure to import stuff. 06:36.790 --> 06:42.340 Initialize communication and then our own kind of void loop. 06:42.370 --> 06:44.690 I'm going to put here 0.01. 06:44.710 --> 06:45.220 Okay. 06:45.370 --> 06:48.300 So we can run this loop at 1000Hz. 06:48.310 --> 06:51.820 And now, well, let's do the servo sweep first. 06:51.820 --> 06:53.740 So we are going to start here. 06:53.740 --> 07:04.840 I'm going to put last time servo move, for example, is equal to time dot time and we have the time 07:04.840 --> 07:05.980 already imported. 07:05.980 --> 07:12.010 And then let's say several delay is equal to. 07:12.280 --> 07:21.730 So we're going to put the different delays after I'm going to start with 005 or let's do actually this, 07:21.730 --> 07:27.730 which is ten milliseconds now in our while true after the time dot sleep. 07:27.730 --> 07:31.210 So I usually put this at the beginning, okay. 07:31.210 --> 07:37.070 Because if you put this at the end of your program and then you have something that is quite big, then 07:37.070 --> 07:40.460 you might miss it or you might put a wrong indentation. 07:40.460 --> 07:43.670 So that's why I usually put that first, okay, as a best practice. 07:43.670 --> 07:49.700 So I don't remove it by mistake or I don't put indentation by mistake, I don't do any mistake. 07:49.700 --> 07:53.060 So any code I write after this time dot sleep. 07:53.060 --> 08:03.260 And so now I do time now is equal to time dot time, which is the current time in second if time dot 08:03.260 --> 08:09.410 now minus the last time servo move if this is greater than the servo delay. 08:09.440 --> 08:13.850 So you can see this is really similar to what we did here for example with the push button. 08:13.850 --> 08:19.100 Okay, time now minus last time is greater than the delay. 08:19.130 --> 08:22.010 That's the exact same code but with Python. 08:22.010 --> 08:31.580 So we do last time servo move is equal to time now and then we can do the action. 08:31.580 --> 08:33.230 So what is the action? 08:33.230 --> 08:35.780 We're going to start from somewhere. 08:35.810 --> 08:36.080 Okay. 08:36.080 --> 08:41.860 So let's say servo angle is equal to 90. 08:41.890 --> 08:44.590 Let's start at 90, okay, which is at the middle. 08:44.590 --> 08:49.720 And we're going to do servo going up is equal to true. 08:49.720 --> 08:54.130 So we start at 90 and we go until 181st. 08:54.130 --> 09:09.040 And so what we do is so if servo going up, then we do servo angle plus one and then else. 09:09.040 --> 09:17.230 So if the servo is not going up, which means it's going down several angle minus one. 09:17.230 --> 09:22.390 And so here the angle was 90 we put true here. 09:22.390 --> 09:26.200 So we go here, the servo angle is going to be 91. 09:26.230 --> 09:29.500 Now we also need to check, of course, when we reach the max. 09:29.500 --> 09:39.920 So if several angle is equal to 180 in that case we are going to do several. 09:40.880 --> 09:50.330 Going up is equal to false so that the next time what we do the next time is we don't go here, the 09:50.330 --> 09:51.470 next time we go here. 09:51.470 --> 10:00.410 And then so the servo angle will be 180, but we do minus one, so 179 and then 178 et cetera. 10:00.410 --> 10:02.450 And then we also need to check here. 10:02.450 --> 10:10.340 If servo angle is equal to zero, then we don't go lower and we do several. 10:11.420 --> 10:16.490 Going up is equal to true. 10:16.490 --> 10:23.450 So the next time we don't go inside this block of code, we go inside this one and we start from zero, 10:23.480 --> 10:29.930 one, two, three, four, five, etcetera, until we reach 180 and then we go back here. 10:29.930 --> 10:31.910 Until we reach zero, we go back here. 10:31.940 --> 10:32.750 ET cetera. 10:32.870 --> 10:33.680 ET cetera. 10:34.190 --> 10:34.640 Okay. 10:34.640 --> 10:41.210 And now that we have the servo angle, so let's skip the indentation we are in that if I'm going to 10:41.210 --> 10:45.200 do command is equal to servo. 10:46.960 --> 10:56.980 Like this plus several angle, but as a string plus backslash n. 10:57.460 --> 11:01.360 Okay, so we make sure that we have the same command as here. 11:01.390 --> 11:02.140 Several. 11:03.160 --> 11:09.280 Colon and then a number k in backslash n for the read string until. 11:09.310 --> 11:10.300 Backslash n. 11:10.720 --> 11:11.140 Okay. 11:11.140 --> 11:12.670 It seems good. 11:12.670 --> 11:14.440 So we just need now to send the command. 11:14.440 --> 11:15.940 So say dot write. 11:16.150 --> 11:21.250 Comment dot encode UTF eight. 11:22.720 --> 11:22.990 Okay. 11:22.990 --> 11:27.190 So we have the delay mechanism with that if. 11:27.520 --> 11:27.690 Okay. 11:27.700 --> 11:32.680 And the time now and we have the sweep mechanism where we change the angle. 11:32.710 --> 11:34.990 Here and then we send the command. 11:35.080 --> 11:37.150 So here we're going to send the command every. 11:37.180 --> 11:38.680 Ten millisecond. 11:39.040 --> 11:46.690 Okay, let's save this as activity six dot p y. 11:47.290 --> 11:49.630 Let's first try this actually. 11:49.630 --> 11:50.230 Okay. 11:50.440 --> 11:54.130 So I am going to run the script. 11:54.160 --> 11:54.760 Okay. 11:54.760 --> 12:01.120 The server is connected and you can see the server is sweeping. 12:01.660 --> 12:02.080 Great. 12:02.110 --> 12:03.110 It's working. 12:03.110 --> 12:09.530 Okay, so here, I'm just going to disconnect that for now so it doesn't make noise and well, let's 12:09.530 --> 12:12.080 continue with the following part of the code. 12:12.080 --> 12:15.200 So Ctrl C here. 12:16.250 --> 12:21.770 So you can see here we already have a sweep command from the Raspberry Pi to the Arduino and we do the 12:21.770 --> 12:24.230 sweep here instead of in the Arduino. 12:24.470 --> 12:31.010 Now I'm going to add a list, so let's add a list here. 12:31.010 --> 12:41.930 Let's do several delays is equal to and so we have 0.005 and 0.01. 12:41.930 --> 12:44.690 So that's all the delays in milliseconds. 12:46.130 --> 12:48.020 So 15 and. 12:48.790 --> 12:49.480 20. 12:50.080 --> 12:51.340 Let's go with that. 12:51.340 --> 13:01.090 And let's say that the several well, actually, let's put that before several delay is several delays. 13:01.330 --> 13:01.990 Zero. 13:01.990 --> 13:03.850 So the first one. 13:05.170 --> 13:05.470 Okay. 13:05.470 --> 13:06.820 So we start here. 13:06.820 --> 13:09.790 We don't start at ten milliseconds. 13:09.790 --> 13:10.990 We start at five. 13:11.020 --> 13:11.560 Okay. 13:11.950 --> 13:17.110 And now well, in order to change that, I'm going to read from the soil. 13:17.230 --> 13:20.620 So we have this first block of code. 13:21.330 --> 13:23.760 So let's put a comment here. 13:25.870 --> 13:31.900 Sweep so we can put some spaces to make it more readable. 13:31.900 --> 13:35.560 And then let's do change. 13:36.660 --> 13:38.070 Several speed. 13:39.570 --> 13:41.430 So the order here doesn't matter. 13:41.430 --> 13:46.350 You could do that before or do that before because we're going to go very fast in this loop. 13:46.440 --> 13:58.590 And so what we do if, say, dot in waiting greater than zero then we do messages is equal to say dot 13:58.620 --> 14:02.100 readline dot decode UTF. 14:03.550 --> 14:06.610 Eight dots airstrip. 14:09.080 --> 14:13.910 We check if message is equal to button pressed. 14:14.750 --> 14:16.430 So let's use that directly. 14:18.070 --> 14:26.860 Then what we simply need to do is to do a change here on the server delay. 14:27.190 --> 14:29.530 And so we need to keep an index actually. 14:29.530 --> 14:35.770 So let's do several delay index is equal to zero. 14:35.800 --> 14:38.590 Let's put that here. 14:39.730 --> 14:39.940 Okay. 14:39.940 --> 14:42.760 And we're going to increment this. 14:42.760 --> 14:46.660 So we're going to do several. 14:48.340 --> 14:51.650 DeLay index plus one. 14:51.700 --> 15:00.580 And of course, we need to check if servo delay index is greater or equal. 15:00.580 --> 15:02.860 So just equal should be enough. 15:02.860 --> 15:11.710 But let's just use that as a more general condition to the length of the servo delays. 15:12.100 --> 15:15.640 So basically, here we are at zero. 15:15.670 --> 15:17.470 We do plus one. 15:17.500 --> 15:21.190 We are at one plus one, we are at two plus one. 15:21.190 --> 15:25.360 We are at three and plus one we are at index four. 15:25.390 --> 15:26.650 That doesn't exist. 15:26.680 --> 15:27.190 Okay. 15:27.220 --> 15:30.370 The length of the list here is four. 15:30.400 --> 15:30.840 Okay. 15:30.880 --> 15:31.960 With the indexes. 15:31.960 --> 15:33.940 Zero, one, two, three, four. 15:34.240 --> 15:36.280 Well, actually zero one, two and three. 15:36.310 --> 15:43.510 If we reach number four, which corresponds to the length of the list, then we are out of the list 15:43.510 --> 15:45.220 and we're going to get an error. 15:45.220 --> 15:49.270 So we check that if we arrive at the length, we simply do. 15:49.390 --> 15:55.540 Servo delay index is equal to zero. 15:55.570 --> 16:00.880 We come back to zero and now we are sure that we have a correct index and we simply do. 16:00.910 --> 16:10.540 Servo delay is equal to several delays with the servo delay index. 16:11.260 --> 16:18.100 And so when we receive the button pressed, we are simply going to change this value here with the next 16:18.250 --> 16:19.990 value on the list. 16:19.990 --> 16:25.810 And this is used where this is used here on this action. 16:25.810 --> 16:28.660 So we are going to change the speed of the action basically. 16:28.660 --> 16:30.970 Okay, let's try that. 16:31.120 --> 16:34.960 So I am going to the Arduino code doesn't change. 16:34.960 --> 16:37.960 I'm going to run this again. 16:40.840 --> 16:44.410 So this level is sweeping. 16:44.410 --> 16:46.840 You can see a little bit faster now every five milliseconds. 16:46.990 --> 16:48.190 Press on the push button. 16:49.030 --> 16:50.410 It's going slower. 16:51.460 --> 16:53.050 I press on the push button again. 16:53.320 --> 16:54.820 It's going slower now. 16:55.000 --> 16:58.570 Every 15 milliseconds I press again. 16:58.930 --> 17:00.650 It's going slower. 17:00.670 --> 17:03.130 Every 20 milliseconds. 17:03.160 --> 17:09.190 And I'm going to press and it's going to come back to the first element, which is five milliseconds. 17:09.500 --> 17:13.990 So five, ten, 15. 17:15.600 --> 17:18.570 And 20 and five again. 17:18.870 --> 17:19.680 All right. 17:19.680 --> 17:25.530 So I'm going to disconnect this just so it doesn't make any noise and the code is working. 17:25.530 --> 17:30.330 So I'm going to press Ctrl C, So here I didn't put any log on the Python side. 17:30.510 --> 17:34.980 You could put some logs here when you actually change the delay. 17:34.980 --> 17:35.340 Okay. 17:35.340 --> 17:37.470 To make sure that you have the correct delay. 17:38.070 --> 17:40.470 Adding some logs here may be too much. 17:40.500 --> 17:40.800 Okay. 17:40.800 --> 17:46.860 If you print a log every five milliseconds to show the angle, you may do that for debugging, but then, 17:46.860 --> 17:49.830 well, maybe that's too much for a normal use of the application. 17:49.830 --> 17:53.460 But here for the change of the delay, why not? 17:53.640 --> 17:54.030 Okay. 17:54.030 --> 17:56.010 And that's the end of this activity. 17:56.010 --> 18:01.890 So here you can see that basically the code that you could do on the Arduino, which is so the application 18:01.890 --> 18:06.810 to make the servo sweep, you can do that also from the Raspberry Pi. 18:06.840 --> 18:07.010 Okay. 18:07.020 --> 18:12.120 So you can choose basically where you control the logic of different parts of your application. 18:12.120 --> 18:19.480 So actually here I did the sweep on the raspberry Pi with Python as a good practice exercise, but maybe 18:19.480 --> 18:25.690 the best option well, depends on your application, but maybe the best option would be to do the sweep 18:25.720 --> 18:27.790 on the Arduino. 18:27.790 --> 18:34.180 So to handle this on the Arduino and then just send from the Raspberry Pi the delay that you want to 18:34.180 --> 18:34.690 use. 18:34.720 --> 18:35.320 Okay. 18:35.530 --> 18:38.230 And the application will be exactly the same. 18:38.260 --> 18:38.470 Okay. 18:38.470 --> 18:44.680 The result will be the same, but the code to sweep the servo would be on the Arduino. 18:44.680 --> 18:44.890 Okay. 18:44.890 --> 18:52.840 So here you can see we are in the example where we could do this here on Python or this on Cplusplus. 18:52.840 --> 18:59.620 And so sometimes it's not necessarily super clear where you should put which code and well, you're 18:59.620 --> 19:03.670 going to simply learn more about that when you practice with this course. 19:03.670 --> 19:08.230 And also after this course, when you practice more and you do more projects, you're going to have 19:08.230 --> 19:13.120 a better idea of what to put on your Raspberry Pi, what to put on the Arduino. 19:13.120 --> 19:13.510 All right. 19:13.510 --> 19:17.410 And that's the end of this section on the Arduino functionalities. 19:17.440 --> 19:23.650 Now we are going to go to the Raspberry Pi functionalities and continue to explore the different things 19:23.650 --> 19:25.630 we can do with Raspberry Pi and Arduino. 19:25.630 --> 19:29.890 And after that, we are going to start the final project of the course.