Message

Introduction

Two VEX AIM Coding Robots can be linked so they communicate during a project. Using Message blocks, the robots can send and receive information to coordinate their actions.

Note: For messages to be sent and received, both robots must be running projects that handle messaging at the same time.

Below is a list of all available blocks:

• send message – Sends a string to the other linked robot.

• send message with data – Sends a string and a number to the other linked robot.

• get latest message – Stores the most recent string received.

• get latest message with data – Stores the most recent string and number received.

• latest message – Returns the most recent stored string.

• latest data – Returns the most recent stored number.

• is message available? – Returns a Boolean indicating whether the other linked robot has ever sent a message.

• is connected? – Returns a Boolean indicating whether the robot is linked with another robot.

send message

The send message block sends a string to the other linked robot.

    send message [message]

Parameters	Description
message	The string to send to the other linked robot.

Example

    when screen [pressed v] :: hat events
    [Press the screen to send a message to the other robot.]
    send message [message]
    when started :: hat events
    [Display when a message is received.]
    wait until <is message available?>
    print [Received!] on screen ▶

send message with data

The send message with data block sends a string and a number to the other linked robot.

    send message [message] with data [0]

Parameters	Description
message	The value to send to the other linked robot. This must be a string.
data	A number to send to the other robot.

Example

    when screen [pressed v] :: hat events
    [Send the current heading to the other robot.]
    send message [message] with data (heading in degrees)
    when started :: hat events
    [Turn to match the other robot's heading.]
    forever
    if <is message available?> then
    get latest message with data
    turn to heading (latest data) degrees ▶

get latest message

The get latest message block stores the most recent string received from the other linked robot.

    get latest message

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Display the received message.]
    wait until <is message available?>
    get latest message
    print (latest message) on screen ▶
    when screen [pressed v] :: hat events
    [Send "VEXcode!" to the other robot.]
    send message [VEXcode!]

get latest message with data

The get latest message with data block stores the most recent string and number received from the other linked robot.

    get latest message with data

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Turn to match the other robot's heading.]
    forever
    if <is message available?> then
    get latest message with data
    turn to heading (latest data) degrees ▶
    when screen [pressed v] :: hat events
    [Send the current heading to the other robot.]
    send message [message] with data (heading in degrees)

latest message

The latest message block returns the most recent stored string from the last use of the get latest message or get latest message with data block.

    (latest message)

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Display the received message.]
    wait until <is message available?>
    get latest message
    print (latest message) on screen ▶
    when screen [pressed v] :: hat events
    [Send "VEXcode!" to the other robot.]
    send message [VEXcode!]

latest data

The latest data block returns the most recent stored number from the last use of the get latest message with data block.

    (latest data)

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Turn to match the other robot's heading.]
    forever
    if <is message available?> then
    get latest message with data
    turn to heading (latest data) degrees ▶
    when screen [pressed v] :: hat events
    [Send the current heading to the other robot.]
    send message [message] with data (heading in degrees)

is message available?

The is message available? block returns a Boolean indicating whether the other linked robot has ever used the send message or send message with data block yet in the current project.

• True - The send message or send message with data block has been used by the other linked robot in the current project.

• False - The send message or send message with data block has never been used by the other linked robot in the current project.

    <is message available?>

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Display when a message is received.]
    wait until <is message available?>
    print [Message received!] on screen ▶
    when screen [pressed v] :: hat events
    [Press the screen to send a message to the other robot.]
    send message [message]

is connected?

The is connected? block returns a Boolean indicating whether the robot is currently linked with another robot.

• True - The robot is linked with another robot.

• False - The robot is not linked with another robot.

    <is connected?>

Parameters	Description
	This block has no parameters.

Example

    when started :: hat events
    [Turn off one of the linked robots to see the message change.]
    forever
    clear screen
    print <is connected?> on screen ▶