WEBVTT

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This is the solution of the previous activity where you need to basically inform Telegram when the Python

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program has connected and disconnected from the Arduino.

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Let's start with the Arduino and well, the code will be super, super easy.

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We just do.

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Serial dot begin and let's use this while not serial okay.

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For compatibility with some Arduino boards and that's it.

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Okay.

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We just want to initialize the communication.

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We don't want to send or receive any message here, so I'm going to just make sure it's connected and

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upload the code.

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Activity number seven.

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Okay.

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We should not have any error here, I hope.

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And don't uploading.

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Great.

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So now let's do the interesting part on the Raspberry Pi side.

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So here we need to do two things.

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First, try to connect to the Arduino and then send a message to Telegram.

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So let's actually do I'm going to remove that.

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Let's write the serial code before so user bin env python three.

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Let's import cereal and let's import time because we will need it and then we are going to retry to

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connect.

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So basically we have the line I'm going to write here.

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Set is equal to cereal dot cereal with the port.

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So the T cm0.

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Let's check.

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It's correct.

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Okay.

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You can check on the terminal or also here.

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Okay.

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ACM zero.

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The baud rate the same.

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On the Arduino.

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And then let's add a read timeout of one second, which we are not going to use here.

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Okay.

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And before we do anything here, let's put that inside a try.

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And so let's add an indentation here.

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Try accept serial.

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Dot cereal exception.

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And before I write the code to handle the exception, let's also put this try except inside a while.

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True loop.

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So an infinite loop.

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So now.

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Well, we're going to enter the while true, we're going to try to connect to see if it works.

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We print successfully connected to Serial and we break.

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Out of the loop, because if we don't break, well, we're going to continue to try to connect to Zion,

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but we are already connected to.

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Okay.

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And if it doesn't work, so if we have the exception.

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We print could not connect to Serial.

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Route trying in, let's say one second dot dot and time dot sleep with one.

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So if we have the exception, we don't break out of the loop.

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So we come back here and we try again.

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Basically, if we manage to go out of this loop, it means we have connected to sail.

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And I'm going to do a time dot sleep three here and then say dot reset, input buffer.

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Okay.

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And then, well, we have our code which for now does nothing.

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So what we could do is just maybe directly close the cell communication or maybe add another Time.sleep,

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for example, for 10s and then close the communication or just add a void loop, kind of a void loop

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here.

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So an infinite loop to keep the program up and then just close the cell communication when we press

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Ctrl C, that's what I'm going to do here.

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So another while true.

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We've time dot sleep well, we can put 0.01 or whatever because here we don't do anything in that while

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loop and I'm going to put this time the while loop inside.

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He try.

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Except.

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Except So here it's going to be keyboard interrupt.

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So in the keyboard, interrupt print closing serial and we do set dot close.

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Okay.

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Note that here to connect we have the try except inside the while true but here we have the while true

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inside the try except okay that's something different.

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So now while the serial code is working, we can add the telegram, but let's just run test it.

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Activity seven.

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Successfully connected to serial and then control C.

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Closing Serial.

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If I disconnect the Arduino board, let's try again.

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Retrain in one second and connect the Arduino board and successfully connect it to control C and okay,

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it works.

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Here we have.

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Okay.

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I did control C when we were in the time.sleep.

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Okay.

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I didn't wait.

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The correct amount of time.

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Maybe let's just add a print here.

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Sale.

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Okay.

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And.

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He wait?

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Three seconds.

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Okay.

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And now let's write the telegram part.

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So import telegram.

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So here we just want to send some notification.

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We don't want to interact with the user on the chat.

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Okay, So let's just do actually from Telegram.

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Import, but and let's create a telegram bot so we can create it.

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Well, we could create it before sale.

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Just going to create it here.

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Okay.

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After we have connected to sale but is equal to bot.

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We've spoken and what we need to give the token.

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So let's do.

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We've open.

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And then let's find this file where we have the token actually, which is in slash home slash API slash

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dot, local slash share and slash dot telegram.

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But token.

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So if you don't have this, please go back and watch the lesson where I saved the token and then with

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R as F and we can do.

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Telegram.

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Token.

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Is equal to.

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F dot read to read all the file because we just have the token dot our strip.

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To remove any unwanted character and token is equal to telegram token.

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Okay, we have the bot ready.

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Let's just do chat ID.

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So actually what chat id we have I'm going to open.

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Our telegram key send notification program we just used before and I'm just going to use this chat ID

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here.

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So use the same as we used previously.

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Okay.

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The bot is now correctly set up and now we can send the message.

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So basically we need to send the message when the serial is connected.

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So the serial is actually connected here.

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But then in the code we wait for three seconds, we reset the input and we consider that it is okay

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here.

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So I'm going to wait.

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Okay.

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To send a message to Telegram after this time.

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Dot sleep.

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Okay.

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So let's do that here.

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Let's do bot dot send message chat id is equal to chat ID and text is equal to, let's say connected

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to Arduino with Serial.

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Let's go to a new line here.

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Here.

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You can send whatever you want.

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Maybe you can send information such as the port, the baud rate.

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Okay.

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But here we keep things simple.

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So we send a message when we have the communication ready to be used.

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And then we also going to send a message here just before we close the sale or maybe just after we close.

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It doesn't really matter here, but dot send message with chat id is equal to chat ID.

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Then text equals to.

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Disconnected

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from Arduino.

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All right, now we can try this code.

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So I'm going to use the Telegram app on the Raspberry Pi.

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You can use the Telegram app on any desktop, any environment you want on your computer, on your phone.

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It doesn't really matter if you use if you have the telegram app on your phone, you're going to receive

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some notifications.

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Okay, let's put that here and let's run the script.

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Okay, wait three seconds and then say, okay, we have a notification here connected to Arduino with

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Serial.

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And then if I press control C closing serial, you can see disconnected from Arduino.

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Okay.

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So using this can be a good way to actually know, for example, if your program is correctly working.

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Okay.

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So if you have a project with Arduino and Raspberry Pi and for example, you want to keep the connection

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alive for a long time, you could try to detect when the communication is down and then send a message

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to the Telegram app so you can be notified as soon as possible and then you can eventually fix this

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problem by yourself.

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All right.

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And that's the end of this activity.