How to properly connect my Arduino with the serial port?

I am working on a project that works with two arduinos. One arduino contains a stepper motor and a servo motor. While the other one only has a stepper motor. However, every time I run my program I always get a, "Error uing serialport".

Here is my program:

%Clear exisiting ports

clear s;

%Setup arduino

a=arduino;

%Set up stepper for x direction

stx=serialport("COM4",9600);

pause(2);

%Set up servo

sr = servo(a, 'D6', 'MinPulseDuration', 700*10^-6, 'MaxPulseDuration', 2300*10^-6);

%Set up stepper for trigger

stt=serialport("COM6", 9600);

pause(2);

%Move launcher

distx=500;

write(stx,int2str(distx),'string');

pause(2);

%Move servo

writePosition(sr, 0);

pause(2);

writePosition(sr, 0.25);

pause(2);

%Move trigger

distt=-500;

write(stt,int2str(distt),'string');

pause(2);

%Move trigger back

distt=500;

write(stt,int2str(distt),'string');

pause(2);

%Move servo back

writePosition(sr, 0);

pause(2);

%Move launcher back to initial position

distx=-500;

write(stx,int2str(distx),'string');

pause(2);

disp("Finish");

Answer 1

[Dhruv]

Based on the error message "Error using serialport", it appears that there is a problem with opening the serial port. This could be caused by several factors, such as the port being used by another program, incorrect port settings, or a faulty connection between the computer and the Arduino.

In the program, which uses two serial ports: "COM4" and "COM6". It's possible that one or both of these ports are not available or are already in use by another program. This can be checked by verifying it in the Device Manager on the computer and looking under the "Ports (COM & LPT)" section to see if the ports are listed and available.

If the ports are available, try adjusting the port settings to make sure they match the settings used by your Arduino code. For example, make sure the baud rate (9600 in your code) is the same on both the MATLAB side and the Arduino side.

If none of these solutions work, check the wiring and connections between the Arduino and your computer. Make sure the USB cable is properly connected and that the correct port is selected in MATLAB.

Also, it's good practice to close any open serial ports before re-running your program.

Hopefully, one of these suggestions will help you resolve the issue.