WEBVTT 00:00.110 --> 00:03.440 This is step number four of the project. 00:03.440 --> 00:10.670 And in this step, we are going to get all the input commands from Serial on the Arduino side and then 00:10.670 --> 00:16.400 make sure that those commands are correctly executed on the hardware components we have connected to 00:16.400 --> 00:17.000 the Arduino. 00:17.650 --> 00:21.610 So we have already initialized all the pins. 00:21.760 --> 00:23.590 Everything we can. 00:23.590 --> 00:25.510 So we have initialized the communication. 00:25.510 --> 00:31.160 We can send also the button pressed command message when we press on the button. 00:31.180 --> 00:37.930 Now what we can do is in this void loop, well, we have this first action, which is to send something 00:37.960 --> 00:39.160 to the side. 00:39.160 --> 00:41.260 And you can see we don't have any delay here. 00:41.260 --> 00:42.310 So it's not blocking. 00:42.310 --> 00:43.960 It's going to be very fast. 00:43.990 --> 00:46.330 We can add after this. 00:47.310 --> 00:50.850 The code to check from Serial if we have received something. 00:50.850 --> 00:54.720 So if serial dot available. 00:56.560 --> 01:07.630 Greater than zero, then we can get the command with let's store as a string cmd is equal to serial 01:07.630 --> 01:15.040 dot read string until backslash n with just one single quote character. 01:15.070 --> 01:20.980 Once we have this command, well, let's see what kind of command we received. 01:20.980 --> 01:24.310 So if cmd and now. 01:24.310 --> 01:27.790 Well, I'm going to come back to the protocol we have defined here. 01:27.820 --> 01:30.640 You can see we have all those commands to handle. 01:30.940 --> 01:36.040 So open door, close door print, text, play buzzer and set led. 01:36.160 --> 01:38.890 So let's write the code for all of that. 01:39.520 --> 01:47.080 So if the command is equal to open door, okay, so if it's equal exactly to open door, then we can 01:47.080 --> 01:48.130 do something. 01:48.130 --> 01:55.210 I'm just going to write all the else if first we have close door. 01:57.000 --> 01:57.540 Okay. 01:57.540 --> 01:59.730 And we're going to close the door with the servo motor. 02:00.300 --> 02:02.700 Else if command. 02:02.730 --> 02:03.510 So. 02:05.100 --> 02:05.460 Here. 02:05.460 --> 02:06.840 This is an exact comment here. 02:06.840 --> 02:13.320 This is a comment that starts with this and then we have some text are some variables we want to extract. 02:13.320 --> 02:15.660 So for those comments, I'm going to do comment. 02:15.690 --> 02:25.920 Dot starts with print, text and colon and two parentheses to close. 02:26.820 --> 02:43.620 Then we have so else if comment starts with we have play buzzer colon and the last one comment starts 02:43.770 --> 02:48.090 with set colon. 02:49.200 --> 02:49.980 Okay. 02:49.980 --> 02:54.510 So as you can see, if you add more comments, it doesn't get more complex. 02:54.510 --> 02:57.510 You just have one more elseif and that's it. 02:57.540 --> 03:01.380 Your program is not going to be more complex and let's do else. 03:01.380 --> 03:04.900 And here I'm going to give you another best practice. 03:04.900 --> 03:06.970 Well, let's say you have received a comment. 03:06.970 --> 03:12.970 So something that you can read from Serial and it doesn't correspond to any of that, which means you 03:12.970 --> 03:15.460 have probably received some garbage comment. 03:15.460 --> 03:20.980 And in that case, what you can choose to do is to also clear the input buffer. 03:21.160 --> 03:21.300 Okay? 03:21.340 --> 03:26.890 Because if you have received something that is wrong, maybe you still have some bytes that have been 03:26.890 --> 03:30.490 received and that are in the buffer that you're going to read next. 03:30.490 --> 03:38.980 And so what we can do is do while dot available greater than zero, let's actually put some parentheses 03:39.700 --> 03:42.520 and we do serial dot read. 03:42.520 --> 03:49.180 So the same thing we did here to clear the input buffer we do it here in the else. 03:49.570 --> 03:51.790 Okay so the else you could choose different behaviors. 03:51.790 --> 03:54.220 You could find some way to print some errors. 03:54.220 --> 04:00.370 So on the LCD screen or maybe send back a comment to the Raspberry Pi that's going to process it and 04:00.370 --> 04:03.640 print it that you have sent an error here. 04:03.640 --> 04:09.250 We just choose to clear the input buffer so that the next time we enter the while loop, we give a new 04:09.250 --> 04:12.280 chance for the Raspberry Pi to send a correct comment. 04:13.950 --> 04:14.580 All right. 04:14.880 --> 04:20.420 Let's also save this as the step number four. 04:20.430 --> 04:21.780 So don't forget. 04:23.380 --> 04:23.760 Okay. 04:23.770 --> 04:24.610 Save. 04:27.220 --> 04:28.480 Let's just verify. 04:28.510 --> 04:31.630 Let's just compile to see that we have the correct structure. 04:31.660 --> 04:32.410 Don't compile. 04:32.440 --> 04:34.840 Okay, so the structure is correct. 04:34.870 --> 04:37.240 Now let's do the commands one by one. 04:37.240 --> 04:39.280 So we have already initialized everything. 04:39.280 --> 04:41.110 That's going to be quite easy. 04:41.320 --> 04:47.590 So if we have the open door command, what we do is simply to send the servo to the position which we 04:47.590 --> 04:51.400 have defined here, the open door position. 04:51.550 --> 04:58.990 So I'm going to do simply servo, dot, write, open the position. 04:59.860 --> 05:02.380 And if we receive the close door. 05:03.710 --> 05:04.630 Command. 05:04.790 --> 05:06.050 We just do. 05:07.680 --> 05:08.180 So. 05:08.190 --> 05:10.280 All right. 05:10.290 --> 05:13.240 We've said we'll close the position. 05:13.300 --> 05:13.470 Okay. 05:13.470 --> 05:16.800 Those are actually the simplest commands to execute. 05:17.460 --> 05:20.760 And well, here what we do is we directly send the command. 05:20.790 --> 05:21.420 Okay. 05:21.630 --> 05:22.440 To the server. 05:22.470 --> 05:27.660 What you could do as an improvement and not gonna do that here, but you can do that as an improvement 05:27.690 --> 05:33.660 is to make the server go a little bit slower with a non-blocking delay mechanism in the void loop. 05:33.660 --> 05:40.050 So you could have another part of the code here that's going to compare the current angle of the server 05:40.200 --> 05:44.220 with the target angle and check if it needs to move a bit. 05:44.220 --> 05:48.810 And every time wait for example, ten milliseconds before it moves for one degree. 05:48.840 --> 05:49.470 Okay. 05:49.740 --> 05:55.020 But here we directly send the command, go to open position, go to closed position. 05:55.560 --> 05:56.040 All right. 05:56.070 --> 05:59.100 Now, when we receive print text, what we do. 05:59.100 --> 06:02.040 So the first thing we do is comment dot remove. 06:02.640 --> 06:04.650 Let's remove the print text. 06:04.650 --> 06:13.810 So we have zero, one, two, three, four, five, six, seven, eight, nine, ten and 11. 06:13.810 --> 06:24.760 So we're going to remove from 0 to 11 and we are left with the text to print so we can do LCD dot clear 06:25.060 --> 06:29.200 to remove anything LCD dot set cursor. 06:30.120 --> 06:36.750 Zero and zero and then LCD dot print cmd. 06:37.350 --> 06:42.720 I'm going to add an improvement here because, well, you're going to just print on the first line and 06:42.720 --> 06:48.330 you have well, you have 16 character on the first line, 16 character on the second line. 06:48.330 --> 06:50.250 And here we just write on the first line. 06:50.250 --> 06:54.350 So everything after 16 character is going to be truncated. 06:54.360 --> 06:59.700 What we could do is that if you receive a string that is more than 16 characters, you bring the following 06:59.730 --> 07:00.690 on the second line. 07:00.690 --> 07:03.180 Okay, so you can use all the 32 characters. 07:03.180 --> 07:12.720 And so what I'm going to do is I'm going to do string line one is equal to comment dot substring. 07:13.200 --> 07:25.920 I'm going to take from 0 to 16 and then string line two is equal to comment dot substring from 16 to 07:25.950 --> 07:27.570 the end of the string. 07:27.600 --> 07:30.060 Okay, so I still clear the screen. 07:30.060 --> 07:35.220 I set the cursor to zero zero and then I print not the comment but print line one. 07:36.780 --> 07:47.010 And then do LCD dot set cursor zero one for the second line LCD dot print line two. 07:47.850 --> 07:48.360 Great. 07:48.360 --> 07:50.640 So that's a bit improved here. 07:50.790 --> 07:52.050 Still has an improvement. 07:52.050 --> 07:58.170 What you can do is, for example, make the text rotate if you have more than 32 characters, because 07:58.170 --> 08:00.900 here after 32 characters, it's going to be truncated. 08:01.320 --> 08:04.110 But let's keep things simple for now. 08:04.410 --> 08:06.300 Then we have the play buzzer. 08:06.300 --> 08:13.260 So with the play buzzer, we're going to do first comment dot remove and let's count zero one, two, 08:13.260 --> 08:18.120 three, four, five, six, seven, eight, nine, ten, 11, 12. 08:18.540 --> 08:29.460 So let's remove 12 And then what we are going to get is so frequency, comma, duration, but we don't 08:29.460 --> 08:35.010 know exactly how many characters this is going to take and how many characters this is going to take. 08:35.010 --> 08:42.160 So what we can do is we can focus on this comma, we can find the index of that comma and then take 08:42.160 --> 08:45.520 everything before the comma and everything after the comma. 08:45.640 --> 08:55.210 And so I'm going to do int comma index is equal to and you have a function that is so on the string 08:55.630 --> 09:05.050 index off like this and you give a character with single quotes like that, it's going to search for 09:05.050 --> 09:08.110 the comma and return the index of the comma. 09:08.440 --> 09:11.560 So of course you need to have a comma in the string. 09:11.710 --> 09:25.720 And once we have gotten this comma index, now we can do int frequency is equal to comment dot substring 09:25.720 --> 09:29.620 from zero to the comma index. 09:31.720 --> 09:40.020 And we are going to also do dot to int to convert this string to an integer and then int duration is 09:40.020 --> 09:47.490 equal to comment dot substring comma index plus one. 09:48.300 --> 09:48.530 Okay. 09:48.540 --> 09:52.590 Because we don't want to actually get the comma in the number. 09:52.620 --> 09:53.160 Okay. 09:53.370 --> 09:59.760 So here we're going to go from zero to the comma index, but this is not going to go until the comma 09:59.790 --> 10:01.710 is going to go just one before. 10:01.950 --> 10:09.600 And when we start again, we start just after the comma to int and now we have the frequency and the 10:09.600 --> 10:10.080 duration. 10:10.080 --> 10:21.690 We can do tone buzzer pin with frequency and duration and that's going to play the tone on the buzzer. 10:21.960 --> 10:22.350 All right. 10:22.350 --> 10:26.640 The last command is settled and so we've already done that before. 10:26.640 --> 10:38.080 So first of all, the command dot remove zero to let's count zero one, two, three, four, 5678 0 10:38.080 --> 10:38.980 to 8. 10:39.160 --> 10:46.270 And then we have something like this and we need to get red, green and blue. 10:46.270 --> 11:03.970 So we do int red is equal to command dot sub string from zero to so 012 and 3.2 int then int green is 11:03.970 --> 11:12.400 equal to so we have 01234567. 11:12.790 --> 11:20.410 So 4 to 7 command dot substring 4 to 7 to int. 11:22.010 --> 11:32.450 And then int blue is equal to comment dot sub string and we're going to start at 01234, five, six, 11:32.450 --> 11:34.460 seven, eight to the end. 11:36.180 --> 11:41.010 To eat now that we have the red, green and blue. 11:41.010 --> 11:42.120 So let's remove that comment. 11:42.150 --> 11:46.920 Now we just do analog, right? 11:47.400 --> 11:49.140 RGB red. 11:50.290 --> 11:52.660 PIN we've read. 11:52.660 --> 11:56.680 And then the same for green. 11:56.680 --> 11:58.090 And the same for blue. 11:59.320 --> 12:01.030 Green and blue. 12:03.380 --> 12:09.810 You can see now our code is about 100 lines, but it's still quite clear. 12:09.830 --> 12:10.130 Okay. 12:10.130 --> 12:14.360 We have first initialization, so some defines and some objects. 12:14.360 --> 12:17.860 We need to create some global variables in the setup. 12:17.870 --> 12:24.020 We start communication, we initialize all the pins, all the components. 12:24.050 --> 12:26.090 Okay, We do some setup actions. 12:26.090 --> 12:32.840 For example, put the servo in a certain position, print some text on an LCD, and then in the void 12:32.840 --> 12:39.080 loop we have first action, which is to check the push button and send the message to Syria. 12:39.200 --> 12:43.580 And second action is to process the data we receive from Serial. 12:43.580 --> 12:47.870 And for each command we have a different block of code. 12:48.440 --> 12:54.470 And well, if you have followed all the previous lessons and activities, you can see that the structure 12:54.470 --> 12:56.720 of the Arduino program is almost the same. 12:56.750 --> 12:56.990 Okay? 12:56.990 --> 13:01.160 That structure that we have here is going to be almost the same in the void loop. 13:01.160 --> 13:05.090 You have all the outputs, all the inputs, and well, that's pretty much it. 13:05.090 --> 13:09.050 If you know how to do this, you know how to do another project. 13:09.050 --> 13:13.310 And you can see here there is no relation between any of the components. 13:13.340 --> 13:15.440 Okay, this is an independent action. 13:15.440 --> 13:17.000 This is an independent action. 13:17.000 --> 13:20.300 Also this one, that one, that one, everything is independent. 13:20.330 --> 13:25.760 The glue or the logic of the application will be from the Raspberry Pi. 13:25.790 --> 13:31.250 So now what we can do is we can test this code actually, because how can you know that it's working? 13:31.250 --> 13:32.630 Well, you have to test it. 13:32.660 --> 13:37.520 Let's upload it to the Arduino. 13:42.880 --> 13:43.150 Okay. 13:43.150 --> 13:47.890 So we have starting on the LCD screen and now let's open the serial monitor. 13:48.250 --> 13:50.500 So let's check that we still have. 13:50.770 --> 13:51.790 Okay, starting again. 13:51.790 --> 13:52.510 Let's check that. 13:52.510 --> 13:54.040 We still have the button pressed. 13:54.040 --> 13:54.670 Okay. 13:55.390 --> 13:59.110 And then I'm going to do print text. 13:59.470 --> 14:00.880 Let's say hello. 14:01.240 --> 14:02.380 It's working. 14:02.380 --> 14:10.060 Let's print some plus some more characters. 14:11.470 --> 14:12.070 Okay. 14:12.100 --> 14:12.430 Hello. 14:12.430 --> 14:16.750 Plus some more characters on the LCD screen and anything that I'm going to write. 14:16.750 --> 14:19.720 So here I use actually 31 characters. 14:20.260 --> 14:24.400 Everything I'm going to write after 32 characters is going to be truncated. 14:24.400 --> 14:26.140 But now you can see that it's working. 14:26.350 --> 14:28.900 So print text is working. 14:29.500 --> 14:31.270 What else do we have? 14:32.260 --> 14:32.970 Open door. 14:32.980 --> 14:34.180 Let's try open door. 14:34.660 --> 14:36.340 So actually the door is closed. 14:36.340 --> 14:38.740 Let's do open door and what? 14:40.990 --> 14:41.680 It's working. 14:41.680 --> 14:42.550 As you can see here. 14:42.550 --> 14:49.240 I had to move a little bit the power, just make sure the power is correctly plugged here. 14:49.240 --> 14:55.600 And this is why this is a limitation of a circuit that you do with a breadboard and some wires like 14:55.600 --> 15:01.690 this is that, of course, the connections may be not 100% stable. 15:01.870 --> 15:02.440 Okay. 15:02.440 --> 15:08.050 So of course, what I recommend is if you try to do this project on a real door is that, well, first 15:08.050 --> 15:14.530 you use a different power supply, use an external power supply for the servomotor, and then you also, 15:14.650 --> 15:16.960 of course, you will need to solder the component. 15:16.960 --> 15:17.200 Okay. 15:17.200 --> 15:18.760 But that's another step. 15:18.760 --> 15:23.980 And just here, that was just here to show you that, well, we have some limitations actually with 15:23.980 --> 15:29.740 a breadboard because all those wires will at the end you will have something that is not working because 15:29.740 --> 15:31.510 something is not correctly plugged. 15:31.870 --> 15:32.560 But here. 15:32.560 --> 15:34.630 So we have open door that's working. 15:34.630 --> 15:36.880 Let's do close door. 15:38.290 --> 15:41.380 And okay, it's working. 15:41.380 --> 15:43.450 So we have closed the open door. 15:43.480 --> 15:45.160 Currently working. 15:45.970 --> 15:46.540 Open door. 15:46.540 --> 15:47.800 Close door print Text. 15:47.800 --> 15:48.670 Play buzzer. 15:50.110 --> 15:52.330 Let's actually do something with that. 15:52.600 --> 15:53.710 Play Buzzer. 15:53.890 --> 16:01.300 Let's send, let's say 400 frequency and 500 milliseconds. 16:02.140 --> 16:03.100 It's working. 16:03.100 --> 16:08.920 Let's send something else like 301,000. 16:10.090 --> 16:11.040 Okay. 16:11.050 --> 16:13.060 It's correctly working and set. 16:14.650 --> 16:25.330 Let's put the right full on 000 and 000 and well, actually, we have an error and it's more like white 16:25.330 --> 16:25.960 and. 16:25.960 --> 16:34.060 Well, that's the of course if I put the red, which was 255 to each one to the right, the green and 16:34.060 --> 16:35.980 the blue, that's going to be white, of course. 16:35.980 --> 16:42.850 So I need to change that to use the green here and to use the blue here. 16:42.850 --> 16:44.950 And let's upload again. 16:50.450 --> 16:50.900 Okay. 16:50.930 --> 16:56.960 Set led to 55 000000. 16:56.990 --> 16:58.040 We have red. 16:58.070 --> 17:00.020 Let's do now. 17:00.200 --> 17:05.390 0002 55. 17:05.420 --> 17:10.520 It should be green and then 000 and 255 at the end. 17:10.550 --> 17:14.540 It should be blue and yes, it is correctly working. 17:15.350 --> 17:15.920 All right. 17:15.920 --> 17:20.180 So now the Arduino code should be done for the application. 17:20.180 --> 17:23.030 So it doesn't mean you don't have to come back to it later on. 17:23.030 --> 17:28.460 Maybe you will need to change or to tweak something because when you program on a Raspberry Pi, you're 17:28.460 --> 17:33.290 going to maybe realize that some stuff on the Arduino should be handled differently. 17:33.410 --> 17:37.970 But still, we should be pretty safe because we already have defined the protocol. 17:38.210 --> 17:38.630 Okay. 17:38.630 --> 17:45.110 We have made sure that all the components are working separately and all the comments are also working 17:45.110 --> 17:46.250 as expected. 17:46.250 --> 17:47.990 And this is the end of this. 17:47.990 --> 17:50.820 Step number four for the final project.