Using Telegram with Raspberry Pi

Until few months ago to communicate with my Raspberry Pi I used Yowsup that is able to connect to the Whatsapp servers.

Unfortunately this method has several issues that made me choose something different... First of all the need of a sim card or at least a phone number not used for other Whatsapp connections, the frequent changes on the Whatsapp protocol and so to the Yowsup libraries that force you to always check for them and eventually update the software and your scripts also on the RPi and least but not last the fact that Whatsapp do not like that their servers are used with a software that is not their messenger!

There are several different solutions to communicate with a RPi. One that I'm using is Pushover, but it's just a one way system (from RPi to the smartphone). It works quite well if you just need text notifications, but if you need something really like Whatsapp the solution could be Telegram.

Probably you already heard about this software. It's quite similar to Whatsapp, but it has many more features that make it a perfect software for our needs. Of course it's free, so you have to pay nothing to use it.

The first thing to note is that Telegram can create bots. A bot is just a "user" without a phone number and it can be managed by a software.

The (really) good thing is that this feature is mantained by the Telegram staff, so they can use the same kind of interface and changing the way it works, without any kind of work by the users.

The bad thing about bots is that they cannot start a chat on their own. You need to add them to a group or start a conversation with them before you can receive from them. Anyway this must be done just once before starting your scripts the first time.

If you need more info about Telegram bots, just visit their intro section.

Now let's see how to create a bot. Of course you need to have the Telegram app installed (note that you can install it also on a computer, not only on smartphones).

Then start a chat with @BotFather. This is the main Telegram bot and you can use it to create your bots:

To create a new bot, just send the command /newbot and BotFather wil ask you to give it a name and then a user name. The user name has to terminate with the string bot:

Note that the user name is stored in the Telegram databases, so it's must have never been used before.

Now the bot has been created and BotFather tells you something important:

The token (in the picture above it's just an example) will be used by our scripts to use the bot, so do not lose it!

You could also change some detail about your bot, like the picture or a description, but this would go beyond the scope of this post.

To use a Telegram bot with a Raspberry Pi you need to install the Python Telegram Bot library. To do so just use the following command from the shell:

pip install python-telegram-bot

if you do not have pip installed, just use this before the previous statement:

sudo apt-get install python-pip

After installing this library we can use it in our scripts. Let's use the following script:

import telegram

# Connect to our bot
bot = telegram.Bot(token="123456789:ABCDabcdefgYGscai2d_hakusnci7Hdks")

# Waits for the first incoming message
updates=[]
while not updates:
    updates = bot.getUpdates()

# Gets the id for the active chat
print updates[-1].message.text
chat_id=updates[-1].message.chat_id

# Sends a message to the chat
bot.sendMessage(chat_id=chat_id, text="It works!")

This is just a small and simple script, just to show you how to get messages and sending them. Let's see how it works...

After importing the library, a new bot is created, The token parameter is exactly the one provided by the BotFather when you created your bot.

Then we just loop waiting for messages. This should be done at least the first time in order to get the chat id needed to send messages with the script. You can also print it and use the value directly the next time as the chat id will remain the same until you delete it.

Note that messages will stay available in the Telegram servers for about 24 hours and then they are deleted. This means that if you cannot receive them (maybe because of an internet connection issue) you could lose them. Another thing you should remember is that if there are messages stored in the servers, the getUpdates command will always return them, even if you already read them, so if you need to wait only for new messages there are more actions to be performed.

At the end we are sending a message to the specified chat and if there are no problems, you should receive the answer from the RPi.

Please remember that this is an extermely simple script to use the Telegram library for Python. With the bot API you can also send and receive photos, audio files, documents and so on. There are tons of features that can be useful and they can also be easily accessed.

Please refer to the Telegram bot API for futher information.

Time permitting (lately I'm quite busy...) I will make a new post with a more complex script to communicate with Raspberry Pi using Telegram. Until then you can surely make your own attempts with the library.