The basic communication we call them are nodes, not communication, how do they work?
We have, let's say, one node, node one we have a node to No.
One, send something to Ross and Node to says, I want that and I will I will do something about it.
And that is what node communication needs.
Node one notices I have something not to say.
I want that something and they start communicating with each other.
That's very simple, right.
Let's take a look on this example, an article on autism I wrote and we have sort of a Tesla like God,
and that is going to be taking an image of the front side of the road that is coming towards the car
when it is moving.
We have a signboard in front of it.
OK, so how this is going to be done with the nodes communication.
We will have a new word that will be published from the car.
OK, that Lord is going to see I have some information about the signboard that is going to be the name
of the information on line line information.
I'm going to call it the topic.
This is the topic.
And I will say that this information is going to be in sort of a message and that message is going to
be of integer type.
Why?
Because we know that signboard we have in the form of an image, because it is coming from a camera.
That signboard board is going to have some sort of a number and that number is going to be represented
in the message.
OK, so that message is going to be of integer type.
I hope you understand the data types of basic python or any other language.
Then we say there is another note node number two that says, I want to know about what signboard is
in front of you.
So what we do is provide this link to this node and it receives that information.
That's how things are going to work.
What the second nor does let's say it uses that information and sends the command of driving the robot.
At a speed of 30 or less generally see the message received from number one, this is going to be in
a sort of some other data type and a topic that is going to be received by node number three and it
will start driving at speed, number to speed, 30 miles per hour, kilometers.
But this is how the basic workflow process works.
It obtains the information from the environment.
In this specific case, it says, I have a signboard in front of my me or the car is saying that.
And that signboard is of value taking.
Some classification algorithm is applied on node number one, use detector design detection algorithm,
then the classification algorithm that classifies it to be auto design.
Then that information is published on DROs three, but then anything on draws with the same address
of local system obtains that information with the help of this topic.
Now, this is important note.
Communication is dependent on topics.
We see any information on the topic.
Sindh is going to be obtained by a subscriber that is node number two that is going to utilize that
knowledge and perform certain thing and then again, publish that on a driving topic.
And after publishing on driving, topic number three says, I want that information of driving so I
can move the robot, the desire to this is how Nords published would subscribe and utilize information
with each other and work together to make the robot move or take action or a lot of things can be done.
Let's clear things up and try some examples as they have provided this said source first and then drive
for this terminal.
We have already sourced things to control shift.
We are running it.
It is a talker.
OK, let's open up a new terminal and run the second listner.
Once one is a talker, one is a list that I already did.
So it will see the Rosta command is not found.
OK, the problem here is the sourcing.
I'll do it manually now.
Source.
OBD, Ross and Foxy.
And that was it, no, it was set up bash, and then actually it is not a code, it is a directory.
It is actually referring to saucing, the Basche file, sort of a script.
So if you want to get into it, take a look into it.
If I go into the first, let's run the command and let's see what happens and then I'll get into the
sourcing stuff.
So there are two things.
One is a one is listner.
And as I have just told you about the Nords, both of these nodes are talking with each and that this
one is publishing the Docker is publishing list that is subscribing.
And as it is printing it, we have received it here and every message publisher publishes Docker's publishes
the listener subscribers and displays on the terminal.
It's just a demo to test whether Uros installation is working or not.
We are not currently going into details of how nodes are working with each other.
OK, next topic for a moment and I'll show you what saucing is actually doing.
OK, source.
And when we.
OK.
Uh.
If I say go into OBD folder and listed, there are three softwares, Google going soft and cross, I
want to go into laws.
It's actually sort of a file manager like this one.
But in Linux, we used to go through commands.
OK, if you're not familiar with Linux, it would be a little bit hard for you.
But don't worry.
So it's like going into folders.
KDDI means going into folder Jane's directory.
Then we go into Foxe and then we see what is inside of Foxe.
There are a lot of things we are just selecting.
Source set up, good batch.
This file, this file placed here is the main file we want to source.
When you want to tell the system viruses installed and we have to source again and again whenever we
open a new terminal.
We have a solution for this, but we talk about it in the next video.