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Arduino is a project and community wich creates open-source software and open-source hardware. The Arduino boards and software are well suited for novices and expierenced programmers alike to create digital devices. In the following we will see how to develop applications for the Arduino boards using SCCharts together with the Arduino Eclipse Plugin. Several open-source, third-party replacements for the offical Lego firmware have been developed. These support many well known programming languages, such as Java, C/C++, Python, Lua, etc. In the following we will use KIELER SCCharts to program Mindstorms running the Lego Java Operating System (leJOS). Therefore we will first install leJOS NXJ and flash its firmware. Afterwards we will create a simple SCCharts project in KIELER that we will compile and deploy to the NXT brick.download and setup the development environment and afterwards create and upload a small example project.

If you want to learn the SCCharts langugage first, you can follow these links:

• Introduction to SCCharts
• The Textual SCCharts Language SCT
• SCCharts Examples

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Download and Configure KIELER

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Note: Java 1.8 is needed on all operating systems. With Java 1.7 not all plugins of KIELER will be loaded. Furthermore on Windows, you will need to download the 32 Bit version of KIELER – even if you have a 64 bit operating system! Otherwise flashing the brick and uploading to the brick will fail.

The Arduino Eclipse

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Plugin

There is an Eclipse plugin for leJOS which adds a project creation wizard and launch configuration to the platformArduino, which makes it easy to create and deploy projects and to use the IDE features of the C/C++ Development Tools (CDT) when programming Arduino.

You have to install

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the plugin manually

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via Help > Install new Software...

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. Use the following update site

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: http:

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/

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/eclipse

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If you have an NXT brick, install the leJOS NXJ Plug-in. If you have an EV3 brick, install the leJOS EV3 plugin.

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After the installation, the plugin requires a little configuration. Go to Window > Preferences > leJOS NXJ (Window > Preferences > leJOS EV3 respectively) and enter the base directory of your leJOS installation in the NXJ_HOME field.

For EV3, the plugin requires the IP address to connect to the brick (it may work without, but its safer to directly set the name. Reduces headache ). Check Connect to named brick and enter the IP adress of the brick (displayed on the brick at startup).baeyens.it/update/V4/nightly

The installation might take a few minutes because it will install the Arduino Tools as well as required software such as the CDT. Furthermore it will download the newest version of the Arduino software and libraries.

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Creating an Example Project

The following shows how to create a project, which will turn on a light if a button is pressedan LED on and off repeatedly.

Create a new project:

1. Choose File > New > Project > KIELER SCCharts > SCCharts Project
2. In the project creation wizard that opens, select Mindstorms NXJ or Mindstorms EV3 (depending on your brick) Arduino as environment and hit finish
3. The project wizard from the leJOS plugin Arduino Eclipse Plugin opens. Set the project name to Flashlight and click Blinky and click next.
4. Set the configuration for your Arduino board. In the field Upload Protocol select Default.
   These settings can be changed later in the project preferences (Right click on project > Preferences > Arduino)
5. Click finish.
6. The project is created and the model file is opened in an editor (This might take a few seconds).

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scchart FlashlightBlinkyModel {
    
    @Wrapper TouchSensorClock, S4500
    input bool buttonclock;
    
    @Wrapper FloodlightDigitalWrite, S113
    output bool light;
    
    initial state lightOff
    --> lightOn with buttonclock / light = true;
    
    state lightOn
    --> lightOff with !buttonclock / light = false;
}

This model will start in the state lightOff. If the button variable clock is pressedtrue, it will turn on the light and change to the corresponding state, where the light is turned off, as soon as the button is not pressed anymoreswitch its state, going from off to on and from on to off. Thereby it sets the light variable so that the led will blink.

The annotations on the input and output variable are used to define which wrapper code is used to set / read them. @Wrapper TouchSensorClock, S4"500" will set the input variable to true iff the touch sensor on the port S4 is pressed. @Wrapper Floodlight, S1 on the output variable will turn on the red led of the light sensor that is attatched to port S1 iff the variable is truefor one tick every 500ms. @Wrapper DigitalWrite, "13" will set pin 13 to HIGH if the variable is true and to LOW if it is false. We assume that an LED is connected to the Arduino board on pin 13.

The available wrapper code snippets are defined in the snippets assets directory of the project in ftl files (FreeMarker template files). In the default configuration of a new SCCharts project for Arduino, the file main.ftl is processed to create the entry point of the program. Thus it includes other templates containing the available code snippets. The table below gives an overview of the available wrapper code snippets.Note: The Floodlight of the EV3 has a pretty high latency when switching between on and off.

Note: To view ftl files with highlighting, you may want to install the FreeMarker IDE feature from the JBoss Tools. However, this is not necessary to work with KIELER. JBoss Tools is available in the Eclipse Market Place and via update site. The update site for Eclipse Luna is stable releases is http://download.jboss.org/jbosstools/updatesneon/stable/lunaupdates/ . Note that only the FreeMarker IDE feature is required (Abridged JBoss Tools > FreeMarker IDE).

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Build the project:

With the mouse over the SCT file in the project explorer, perform Right Click > Run As > KiCo Compilation.

A launch config is created, which compiles the model to Java code and creates wrapper code from the annotations in the model file. Afterwards this output is compiled and deployed to the Mindstorms brick, by using the launch shortcut from the leJOS plugin. If any errors occur, you can see them in the Console View.

For a deeper understanding of the project launch and initialization, take a look at the wiki page for PromAfter the modeling is done, the project can be built. Select Project > Build Project. This will create a new folder kieler-gen with the compiled model file. Further the wrapper code for the model is processed. After the build finished sucessfully, the ino file for the project has been updated with the new wrapper code for the model, and thus the project can be deployed to the Arduino board. The Eclipse Arduino Plugin provides an upload button for this task in the toolbar.

Excluding the simulation folder from the CDT build

A simulation of models is created as part of a build inside kieler-gen/sim/bin. The files inside the sim folder are compiled separately and should not be compiled using the CDT. Otherwise errors will occur, for example because every simulation has its own main function and the CDT expects only one for the project.

Thus the folder kieler-gen/sim has to be excluded from the CDT build. Therefore select the folder and do Right Click > Resource Configurations > Exclude From Build.

Simulating the model

To use the simulation inside the folder kieler-gen/sim/bin, first change to the Simulation Perspective, which provides new buttons in the toolbar. The executables in the bin folder can then be launched via Right Click > KIELER Simulation. The output of a running simulation can be seen in the Data Pool View.

Available Wrapper Code Snippets

There are several wrapper code snippets that can be used as annotations on input and output variables in the model file. These snippets are inserted in the main file template as part of the project launch. The available snippets are listed below.

For sensors, the port has to be on of S1, S2, S3, S4.

For motors / actuators the port has to be one of A, B, C, D.

Using the Remote Console (RConsole)

The display of the NXT brick is rather small compared to a Monitor. To ease debugging, one can print to a Remote Console (RConsole), if the USB cable is connected. This enables easier collection for example of sensor data.

To use the RConsole, uncomment the RConsole lines in the wrapper code template Main.ftl. Start the nxjconsoleviewer tool in the bin directory of your leJOS installation. Now, when starting the application, the brick tries to connect with the nxjconsoleviewer. Press the Connect button. If connected succesfully, RConsole.println(...) commands will be written to this window.

The EV3 brick has a similar feature. However it does not require any code changes. Just run the ev3console program in the bin directory of your leJOS installation from command line. The output of the brick will be printed to this command line.

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Using the Serial Monitor

The Arduino Eclipse Plugin has a Serial Monitor (Window > Show View > Other > Arduino > Serial monitor view). Here you can open connections to serial ports and read and write to them.

To open a connection, click the plus button and select the serial port you want to conenct to as well as the serial rate that is used to transmit data. Click OK.

The output of all open connections will be combined in the text editor.

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Problem Solving

The following presents typical issues and how to solve them.