WEBVTT

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All the robot's hardware, its arms and the gripper will be actuated by servo motors that are connected

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to the Arduino Uno or any compatible board.

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The goal of the first lesson in this course, therefore, is to establish a bidirectional communication

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between the Arduino and our PC, where Ros two is running.

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At this point in the course.

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The architecture of our project involves a PC running Ros two with all the logic.

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So we told the application that the robot is using such as Move It Ros to control the task server and

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also the interface with Alexa.

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And on the other end there is the microcontroller that controls the robot's motors and possibly reads

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data from the sensors you want to equip the robot with.

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This is our typical architecture of our robotics project.

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On one side, there's the electronics, mechanics, sensors and actuation.

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These components are often managed by a microcontroller board with normally with limited computing and

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memory capabilities.

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Typically, the only objective of this board is to read data from sensors and send actuation commands

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to the motors.

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All the logic, the functionalities and the software of the robot are on the other side, often lying

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on a PC with a microprocessor and possibly a graphics card that is capable of processing vast amounts

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of information and running various applications in parallel.

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Generally, this is where the logic to process sensor data is contained.

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For example, to detect the presence of an obstacle near to the robot and to calculate the trajectory

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and the actuation command for the robot.

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To connect these two words, the hardware and the software.

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We can use serial communication through a classic USB cable and use it to transmit those two messages

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to the Arduino in binary format.

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In this way we can use the same publisher subscriber communication protocol that is available in Ros

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two to serialize messages and publish them, sending them to the Arduino, which can then read those

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messages that are passing through the Ros two topics and also publish some new messages.

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However, when we do this, that is when we use the Arduino to exchange messages with other Ros two

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nodes.

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We mustn't forget that this board has limited computational and memory capabilities.

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Therefore, we must pay a particular attention to the size of the Ros.

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Two messages that we are going to use, and we have to ensure that they contain only the necessary information

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and no overhead.