make a string to send it as a serial data.

Hello I want to control servo from simulink using Serial Send block. The servos are connected to an arduino which receives position values in following format.

servoID:pos&servoID:pos&servoID:pos

for example 1:255&2:123&3:120 I have a code that calculates these values but i don't know how to send this values in precise string format. Please help me with this. Its really urgent and part of my final year project.

Thank you!

Answer 1

[the cyclist]

You should be able to use the sprintf command to format your string:

sprintf('%d:%d&%d:%d&%d:%d',[1 255 2 123 3 120])

I just used some explicit values for the second argument, but you can use variables there instead. If you carefully read the documentation, you'll see that the command has a lot of flexibility.

[Bhargav Jha]

Thank you for the answer. But I need to do it using a simulink block. I tried to output a string from the matlab function block and it doesn't allow me to do that. I want to send this string to a arduino board using the serial port. Is there a way to do this in simulink?

[Walter Roberson]

Use a MATLAB function block and

output = uint8( sprintf('%d:%d&%d:%d&%d:%d',[1 255 2 123 3 120]) );

The result would be a uint8 vector, and those can be passed between blocks in Simulink.

Just watch out for fixed length vs variable length at the signal level.

Also if you are using any of the acceleration modes, then you will need to use one of the methods of declaring the vector to be variable length; see https://www.mathworks.com/help/fixedpoint/ug/defining-variable-size-data-for-code-generation.html

Answer 2

[Iris José do Amaral Neto]

I want to send this string to a arduino board using the serial port. Is there a way to do this in simulink? Has anyone ever managed?

[Kubilay DUMAN]

By using above blocks, I was able to send following string by serial communication;

"Pot_value:544 PWM:17 Rot:1"

Note that compose string block does not take unsigned values.