Set up and Blink - MATLAB and Simulink with Raspberry Pi

Version 6

    Overview

    RaspberryPiOverview.png

    You can use MATLAB to communicate with a Raspberry Pi board and its peripheral devices using MATLAB Support Package for Raspberry Pi.

    You can program Raspberry Pi boards to run your algorithms using Simulink Support Package for Raspberry Pi Hardware. The support package generates code from your Simulink model in a click of a button that then runs on the Raspberry Pi board.

    This tutorial covers a step-by-step guide to:

    MATLAB Support Package

    1. Set up the MATLAB support package for Raspberry Pi.
    2. Send commands from MATLAB to Raspberry Pi to blink the on-board LED.

    Simulink Support Package

    1. Set up the Simulink support package for Raspberry Pi.
    2. Build a simple Simulink model for controlling pins on the Raspberry Pi.
    3. Generate, download and run code on the Raspberry Pi to blink the on-board LED.

    In this tutorial Raspberry Pi 2 is used as an example, however the same steps can be used for other boards like Raspberry Pi Model B+ etc.

     

    Software

    MATLAB and Simulink Student Suite Release 2015a - now available for $99

    If you are not a student, you can purchase the MATLAB Home-Use license for personal use:

    Hardware

    1. Raspberry Pi 2
    2. USB Cable
    3. Ethernet cable

     

     

     

    Setup MATLAB and Simulink Support Packages for Raspberry Pi

    1) Open MATLAB and click the Add-Ons drop down menu on the top right. Click on Get Hardware Support Packages in the drop down menu to start the installer.

    Picture2.png

    2) Select 'Install from Internet' as the source for installing the support package and click next.

    Picture6.png

    3) On the list of support packages select Raspberry Pi and click Next, to install both the support packages at once.

    RaspberryPiSelect.PNG

    4) Log in to your MathWorks account. If you don't have a MathWorks account, you can create one during the install process or by visiting this page on the MathWorks website.

    Picture9.png

    5) Once you accept the license agreement on the next screen, click Next through the following screens to finish the installation of both MATLAB and Simulink Support Package for Raspberry Pi.

    RaspberryPiSuccess.PNG

    6) On the Firmware Update page, select the appropriate board (for this tutorial, Raspberry Pi 2 Model  B is chosen).

    RaspUpdateFirmware.png

    7) In the configure network screen, select Direct connection to host computer (to follow along with this tutorial).

    RaspConfigNetw.PNG

    8) In the next window titled 'Select a drive', the MicroSD cards that are detected by MATLAB will show up in a list format. If the MicroSD memory card does not get detected by MATLAB, but is detected by the OS - close MATLAB and restart MATLAB as an administrator. To continue with the process, the targetupdatercommand can be used in MATLAB.

    RaspSelectDrive.PNGRaspWriteFirm.PNG

    9) Select write option to erase existing items on the memory card and flash the latest firmware that is needed by the Support package. Click Next through the following screens to finish the installation for both MATLAB and Simulink Support Package for Raspberry Pi.

    Blinking On-board LED Using MATLAB Support Package for Raspberry Pi

    To establish a connection between MATLAB and Pi 2, the following command can be used from MATLAB.

    >> mypi = raspi

    This command connects MATLAB to the most recent successful connection to a Raspberry Pi board, including the setup process. A MATLAB variable by the name 'mypi' should now appear on the workspace or an error message indicating what went wrong. This object represents the connection that MATLAB has established with the physical object (Raspberry Pi).

    RaspiConn.PNG

    To switch on the on-board LED connected, execute the following command

    >> writeLED(mypi,'led0',1)

    Here we are sending a request from MATLAB to Raspberry Pi board, to write the value of 1 on the on-board LED. This should switch ON your LED.

    To blink the LED, we have to switch it ON and OFF periodically.

    for i = 1:10
        writeLED(mypi,'led0',1);
        pause(0.5);
        writeLED(mypi,'led0',0);
        pause(0.5);
    end

    Other functions that are related to the MATLAB Support Package for Raspberry Pi can also be used along with the Raspberry Pi object 'mypi'. To take a look at the featured examples from MATLAB Support Package for Raspberry Pi, type raspi_examples in MATLAB Command Window.

    Common Error Messages

    Error using raspi (line 157)
    Cannot establish an SSH connection to the board with device address "169.254.0.2".

    Caused by:
    Error using raspi (line 153)
    Error executing command: FATAL ERROR: Network error: Network is unreachable

    Ensure that the Raspberry Pi board is connected to the computer that you are working with. Usually when the lights on the ethernet port and the ACT LED are blinking, there is a connection between the Pi board and the computer.

    If for some reason the connection between MATLAB and Raspberry Pi board is lost, the following error message appears.

    The host and client connection is lost. Make sure the board is plugged in and/or recreate arduino and its related objects.

    The best practices to follow to resolve this error -

    1. Disconnect the USB cable and Ethernet cable from both the Pi board and computer.
    2. Clean up MATLAB by typing clear in MATLAB Command Window.
    3. Plug in the USB cable to computer and Pi board.
    4. Try connecting to the board from MATLAB by using raspi command.

     

    Blinking On-board LED Using Simulink Support Package for Raspberry Pi


    Create your own Simulink model

    1) In MATLAB, select New > Simulink Model under the HOME Tab.

    newSimulinkModel.png

    2) Click on the Library Browser Icon on the simulink model and go to Sources tab under Simulink in the Simulink Library Browser window.

    SourcesTab.png

    3) Drag the Pulse Generator block from the Sources library to your model and change the values as shown here.

    PulseGen.PNG

    4) Use the LED Block from Simulink Support Package for Raspberry Pi Hardware in the Library Browser and change the parameters as shown here.

    LEDinLib.PNG LEDBlockParam.PNG

    5) Drag and drop the Data Type Conversion block from the Signal Attributes tab under the Simulink library.

    ConvBlock.PNG

    6) When you move the mouse pointer close to the arrow on the block, it will change to a plus sign. Left click when you seee the plus sign and drag the mouse to make the intended connection. Once the connection is made you can release the left click button. 

    myBlinkingLED.PNG

    7)  Save this model and to configure the model go to Tools > Run on Target Hardware > Prepare To Run...

    PrepareTarget.PNG

    8) When the Configuration Parameters page opens up, set the Target hardware parameter to Raspberry Pi. Do not change any other settings.

    configModel.png

    9) In your Simulink model, click the Deploy To Hardware button on the toolbar. Code will be generate from the model, which is then deployed to your Pi 2. The on-board LED should blink one time every second.

    DeployToRas.png