If you want to read Arduino analog input into MATLAB, take a look at the readVoltage function:
https://www.mathworks.com/help/supportpkg/arduinoio/ref/readvoltage.html?searchHighlight=readvoltage&s_tid=doc_srchtitle
If you want to read it into Simulink, check out all the Arduino examples / tutorials at:
https://www.mathworks.com/help/supportpkg/arduino/examples.html#d0e29
Depending on which application you are looking for, make sure you use the MATLAB add-in installer to get the corresponding Ardunio Support Package (MATLAB Support Package for Arduino Hardware and/or Simulink Support Package for Arduino Hardware)
