Using Robot-to-Robot Messaging with VEX AIM – VEX Library

The VEX AIM Coding Robot provides students with an easily accessible way to experience robot-to robot messaging, or communication, between two linked robots. This article describes what robot-to-robot messaging is, why it is important, and how to get started using it.

What is Messaging?

Two VEX AIM Coding Robots can be linked so they can send and receive messages during a VEXcode AIM project. Because robots can communicate and work together, they can tackle more complex projects than one robot could on its own.

In the example video below, both robots are linked and running the same project. When the screen is pressed on one robot, it sends a message to the other robot to turn its LEDs to blue.

Messaging enables two robots to act in coordination to accomplish tasks, as one robot can make decisions based on data sent from another. For example, one robot can signal another to:

start a project.
take evasive action to avoid an obstacle.
call for assistance from another robot.

Robot-to-robot messaging is used in many real world contexts. For example, warehouse robots send messages to let each other know their locations, to ensure they don't collide. Search and rescue robots can send messages to communicate the locations of those who need help, or to signal which areas they have covered to help their teammates spread out efficiently and avoid duplicating work.

Why is Messaging Important?

Incorporating messaging into VEXcode projects allows students to experience these real world connections in the classroom. It can be a useful way for students to experience systems thinking, as students go through the process of breaking down how two robots will work together to achieve a goal. It also requires them to communicate clearly and engage in collaborative problem solving to coordinate their coding projects so their robots can successfully use messaging to work together.

To learn more about the benefits of teaching with robot-to-robot messaging, see this PD+ Insights Article.

Getting Started with Messaging

Linking Two Robots

The Link AIM screen on a VEX AIM robot showing two green robots with a checkmark and curved lines indicating connection between them.

Before two robots can send and receive messages, they must first be linked. Follow the instructions in this article to link your robots.

Using Example Projects in VEXcode

There are example projects available in VEXcode for both Blocks and Python that can be used to develop an understanding of how to code with messaging.

For additional information about using example projects with VEX AIM, see this VEX Library article.

The message filter at the far right highlighted at the top of the Example Projects page in VEXcode

Select the message filter to display the messaging example projects.

The Bidirectional LED Control example project shows how two robots can run the same program at the same time. Each robot sends messages to the other, and those messages make the robots respond with a specific behavior.

When the screen is pressed on one robot, it sends a message to the other robot to set its LED colors to blue.

Example project icon for the Receiving Messages project on the left and the Sending Messages project on the right. Each icon shows a robot with an orange barrel above it and an arrow pointing to the top of the other robot.

The Sending Messages example project and the Receiving Messages example projects work together. The Sending Messages example project is downloaded to one robot (Robot A), and the Receiving Messages example project is downloaded to the other (Robot B).

The project shown in the video above is described in the table below.

Robot A	Robot B
Press the screen to collect data.	Wait for a message.
Depending on what AI Vision detects, send a message.	Depending on the message received, turn the LEDs on to a specific color and play a sound.

Teaching with Messaging

Incorporating messaging into your classroom opens up many opportunities for students to practice their own communication and collaboration while building exciting projects for their robots. As they design systems for robots to share messages, students practice organizing information, agreeing on rules, and troubleshooting when things go wrong—skills that directly mirror real-world collaboration. The following suggestions will help teaching with robot-to-robot communication in your classroom:

Two groups of students should work together to create messaging projects. Each group will need their own robot.
Be mindful of spacing when students are linking robots. Having just two robots in the same space when linking will help prevent confusion.
Once robots are linked, mark robot pairs so they can easily be identified. Use unique matching colored stickers or tape for each pair so students can find them quickly.
- Note: once a pair of robots are linked, they will remain linked the next time they are turned on. There is no need to repeat the linking process.
The example projects described above are great starting points for helping students understand messaging.
- First, students can read the projects and predict what they think will happen.
- Next, they can run the projects to see how the work.
- Finally, they can modify the projects to make them their own.
The following VEX AIM Activities are also available for introducing messaging in your classroom:
- Send and Receive - In this Activity, students work collaboratively with another group to code two linked robots so one instructs the other to clear blue barrels from the field.
- Soccer Practice - In this Activity, students work collaboratively with another group to code two linked robots to kick a sports ball back and forth.