WEBVTT 00:00.110 --> 00:05.720 This is the first step of the final project where we build a complete intercom system. 00:05.720 --> 00:09.950 And for this step, well, we are not going to write any code. 00:09.950 --> 00:16.220 We are going to define the protocol we will use to communicate between the Arduino and the Raspberry 00:16.220 --> 00:20.030 Pi and also between the Raspberry Pi and the Telegram application. 00:20.030 --> 00:20.420 Okay? 00:20.420 --> 00:27.020 Because when you communicate between both sides, you need to agree on what you send and what you receive 00:27.020 --> 00:30.770 so you can correctly process the comments and the messages. 00:30.770 --> 00:38.210 So I'm just going to open well, just I'm going to open Genie here just to write some text. 00:39.710 --> 00:45.080 So what you can do, what I would recommend is just write the protocol on paper first. 00:45.110 --> 00:45.290 Okay? 00:45.290 --> 00:46.610 Just a pen and paper. 00:46.610 --> 00:47.480 That's it. 00:47.810 --> 00:54.320 Or just open any text editor you want on the Raspberry Pi or on your phone, on Windows or. 00:54.320 --> 00:56.060 Well, basically any way you want. 00:56.090 --> 00:56.270 Okay. 00:56.270 --> 00:57.320 It doesn't really matter. 00:57.320 --> 01:03.510 It's just to write the protocol that then you keep on the side for the duration of the project. 01:03.510 --> 01:08.580 So first of all, we're going to focus on serial communication. 01:10.700 --> 01:12.070 We're not putting full size. 01:12.080 --> 01:12.740 Okay. 01:13.250 --> 01:18.560 And then on telegram communication. 01:21.620 --> 01:23.140 So what do we need for soil? 01:23.150 --> 01:28.790 So basically between the Arduino and the Raspberry Pi, first let's do the commands that are going to 01:28.790 --> 01:31.430 go from Arduino to Raspberry Pi. 01:31.460 --> 01:34.120 I'm going to write a Pi like this. 01:34.130 --> 01:35.210 What do we have? 01:35.210 --> 01:40.490 Well, we have just one output we want to send is when we press on the push button. 01:40.490 --> 01:48.350 And when we press on the push button, we can send the command, for example, button pressed with backslash 01:48.350 --> 01:53.030 n Okay, I'm going to add backslash n here so that the command is complete. 01:53.540 --> 01:55.100 So we send this. 01:55.100 --> 01:58.790 So we've already done that actually in some of the previous activities. 01:58.790 --> 02:03.320 We send this from the Arduino, we receive that on the Raspberry Pi, then that's it for this side of 02:03.320 --> 02:04.430 the communication we have. 02:04.430 --> 02:09.860 Then the API to the Arduino here we have a few more comments. 02:09.860 --> 02:17.270 So we are going to control the RGB led the buzzer, the servo motor and the LCD screen from the Raspberry 02:17.270 --> 02:17.690 Pi. 02:17.690 --> 02:21.060 And so what commands exactly are we going to send? 02:21.060 --> 02:23.850 Let's first think about the servo motor. 02:23.880 --> 02:29.460 So basically the command we want to do is not to move the servo motor in a at a high level. 02:29.460 --> 02:35.010 It's more to open the door or to close the door because this is an intercom project where the servo 02:35.010 --> 02:36.600 motor is linked to the door. 02:36.900 --> 02:46.140 So what I'm going to do is I'm going to send a command open door backslash n and close the backslash. 02:46.140 --> 02:53.350 N And the Arduino will be responsible for moving the servo to the correct position when it receives 02:53.400 --> 03:00.570 open door and moving the servo to the closed position when it receives the closed door command. 03:00.600 --> 03:00.900 Okay. 03:00.900 --> 03:03.810 I could send directly the angle of the servo to the Arduino, but. 03:03.810 --> 03:06.300 Well, actually this way may be better. 03:06.300 --> 03:06.540 Okay. 03:06.540 --> 03:11.820 We send open door closed door and the Arduino knows because the Arduino is closer to hardware, the 03:11.820 --> 03:18.120 Arduino knows what is the angle to send the servo to, what is the speed to move the servo, etcetera. 03:18.150 --> 03:23.490 Okay, so we are done with the servo and with the open and close door functionality is then when we 03:23.490 --> 03:28.740 open and we close the door, we also want to set the Led the buzzer and the LCD. 03:28.890 --> 03:30.300 So let's start with LCD. 03:30.330 --> 03:41.670 We are going to send print, text, colon and then let's say this is some text backslash N So we have 03:41.670 --> 03:42.900 already done that before. 03:42.900 --> 03:49.890 We send the print text command with Colon, and then we're going to extract this from the command. 03:50.220 --> 03:52.290 So this is an exact command. 03:52.290 --> 03:55.200 We are going to check if it's equal to open door here. 03:55.200 --> 04:01.110 We are going to check if the command starts with print text and then extract this and print this on 04:01.110 --> 04:02.250 the LCD screen. 04:02.250 --> 04:03.660 Now for the buzzer. 04:03.660 --> 04:09.510 Well, we haven't used the buzzer in any activity before, so that's something new. 04:09.540 --> 04:12.450 What can we do to send comment to the buzzer? 04:12.450 --> 04:19.500 So we want to play a sound on the buzzer And to play a sound, we need to give two things the frequency 04:19.500 --> 04:21.240 and the duration. 04:21.240 --> 04:23.730 And so I'm going to put a comment. 04:23.730 --> 04:24.840 Let's say play. 04:26.130 --> 04:29.910 Buzzer column and then frequency. 04:32.000 --> 04:35.120 Comma, duration backslash n. 04:35.270 --> 04:41.120 So on the Arduino, we're going to first check that we have a command that starts with play Buzzer Colon 04:41.120 --> 04:43.020 and then we're going to extract. 04:43.040 --> 04:49.880 So this and we're going to find the index of the comma and then everything before the index is the frequency. 04:49.880 --> 04:52.330 Everything after the index is the duration. 04:52.340 --> 04:52.570 Okay? 04:52.580 --> 04:57.170 So the frequency can be anything from, let's say, 20Hz to 20,000Hz. 04:57.170 --> 05:02.840 And the duration also can be anything from one millisecond to whatever milliseconds you want. 05:02.840 --> 05:16.370 And then we have set led because we want to set the RGB led with red, green and blue backslash n And 05:16.370 --> 05:21.980 so here we're going to follow the protocol we have used previously in one of the other activity, which 05:21.980 --> 05:25.820 is to say that each color will be exactly three characters. 05:25.850 --> 05:26.050 Okay. 05:26.060 --> 05:38.310 So as an example, we have set led, let's say you want to give three for the red and then 255 for the 05:38.310 --> 05:43.080 green and then zero 50 for the blue. 05:43.320 --> 05:48.810 Okay, You're going to make sure that each color gets three characters. 05:49.290 --> 05:49.770 Okay. 05:49.770 --> 05:53.160 And let's just actually do an example for the play buzzer. 05:53.730 --> 06:04.590 The buzzer, let's say, for example, 201,000, so 200 frequency, 1000 milliseconds. 06:04.590 --> 06:09.870 And so we're going to handle actually those two commands a bit differently in the code, in the Arduino 06:09.870 --> 06:10.430 code. 06:10.440 --> 06:18.270 So we have covered all the functionalities here and all the components between the Arduino and the Raspberry 06:18.270 --> 06:18.540 Pi. 06:18.660 --> 06:20.820 So we're going to keep this on the side. 06:21.150 --> 06:26.370 And so when we work on the Arduino, we know what to send and what to receive. 06:26.370 --> 06:31.050 And when we work on the Raspberry Pi, we know what to receive and what to send. 06:31.350 --> 06:31.530 Okay? 06:31.530 --> 06:34.260 We don't need to always compare the two codes. 06:34.260 --> 06:36.330 We can just refer to this document. 06:36.330 --> 06:42.930 And then we also need to define what command we are going to send and receive from Telegram. 06:42.930 --> 06:50.670 So well, when we actually send the notification with a message and a photo, there is no specific comment 06:50.670 --> 06:58.080 to agree on because we're just going to send a message on the chat using the chat ID, But when we receive 06:58.080 --> 07:03.480 command, we need to check what command we receive so we can process them with a handler in the Python 07:03.480 --> 07:03.930 code. 07:03.930 --> 07:07.080 And so we're going to have the start command as always. 07:07.080 --> 07:13.020 And then to open the door, we are going to use open like you could see in the demo and to close the 07:13.020 --> 07:18.360 door actually to deny access, not to close the door, but to deny access, just deny. 07:18.870 --> 07:22.320 So we start we can get a welcome message. 07:22.320 --> 07:29.370 When we receive a notification we can send open to open the door or we can send deny to deny the access. 07:29.370 --> 07:32.880 And well, that's pretty much it. 07:33.460 --> 07:35.410 So I'm going to save control. 07:35.410 --> 07:40.060 S this as protocol dot txt. 07:42.040 --> 07:42.520 Okay. 07:42.520 --> 07:45.550 And keep it on the side for the duration of the project. 07:45.550 --> 07:52.120 And now that we have this we are ready to start writing some code with the next step.