MATLAB/Octave - API Bindings

The MATLAB/Octave bindings allow you to control Bricks and Bricklets from your MATLAB/Octave scripts. The ZIP file for the bindings contains:

  • matlab/Tinkerforge.jar, a precompiled Java library for MATLAB
  • in matlab/source/ the source code of Tinkerforge.jar for MATLAB
  • in matlab/examples/ the MATLAB examples for every Brick and Bricklet
  • octave/Tinkerforge.jar, a precompiled Java library for Octave
  • in octave/source/ the source code of Tinkerforge.jar for Octave
  • in octave/examples/ the Octave examples for every Brick and Bricklet

The MATLAB/Octave bindings are based on the Java bindings.

Requirements

  • MATLAB or Octave 3.6 with Java support

Installation

Before you and use the bindings with MATLAB or Octave you have to install them.

MATLAB

The Java support in MATLAB is typically enabled by default. You can test this with the following command in MATLAB:

version -java

If this command doesn't show Java support then see the MATLAB documentation about how to configure Java for MATLAB.

To use the bindings MATLAB needs to know where to find the Tinkerforge.jar file. There are several ways to archive this, see the MATLAB documentation for more details on all of them. The recommended way is to the add the bindings to the preferences folder.

Start MATLAB and run the following command to get the path of the preferences folder:

prefdir(1)

Preferences folder path examples:

  • Windows: C:\Users\<user>\AppData\local\MathWorks\MATLAB\R2016a
  • Linux: /home/<user>/.matlab/R2016a
  • Mac OS X: /Users/<user>/.matlab/R2016a

Copy the Tinkerforge.jar file from the matlab/ folder to the preferences folder. Then the Tinkerforge.jar file has to be added to MATLAB's class path. Edit or create a file named javaclasspath.txt in the preferences folder and add the absolute path to the Tinkerforge.jar file as a new line to it. For example:

  • Windows: C:\Users\<user>\AppData\local\MathWorks\MATLAB\R2016a\Tinkerforge.jar
  • Linux: /home/<user>/.matlab/R2016a/Tinkerforge.jar
  • Mac OS X: /Users/<user>/.matlab/R2016a/Tinkerforge.jar

Restart MATLAB and run the following command, it should list the Tinkerforge.jar file:

javaclasspath

The bindings are now ready to use.

Octave

If Java support is available in Octave depends on the Octave version. Until version 3.6 (inclusive) Java support was in a separate module. Since version 3.8 it is available by default.

But in Octave 3.8 callbacks don't work, see the known problems section. We recommend Octave 3.6 for now.

On Linux you have to install an extra package for the Java support in Octave 3.6:

sudo apt-get install octave octave-java

For Windows we recommend the MinGW build of Octave, because it comes with Java support by default. The Octave Wiki has a guide about how to set up Octave for Windows.

You can test if Java support is available with the following command in Octave:

octave_config_info("features").JAVA

To make the bindings available in Octave the Tinkerforge.jar from the octave/ folder has to be added to Octave's class path. This can be done with the following Octave command on Windows:

javaaddpath("C:\\Absolute\\path\\to\\Octave\\Tinkerforge.jar");

Or by this Octave command on Linux:

javaaddpath("/Absolute/path/to/Octave/Tinkerforge.jar");

To make this change persistent you can add the command to the following file on Linux:

~/.octaverc

If this file didn't exist yet you can just create it. Octave has to be restarted after changing this file.

Testing an Example

To test a MATLAB/Octave example Brick Daemon and Brick Viewer have to be installed first. Brick Daemon acts as a proxy between the USB interface of the Bricks and the API bindings. Brick Viewer connects to Brick Daemon and helps to figure out basic information about the connected Bricks and Bricklets.

MATLAB

As an example we will run the Stepper Brick configuration example. To do this open the matlab_example_configuration.m file from the matlab/examples/brick/stepper/ folder in MATLAB.

In the example HOST and PORT specify at which network address the Stepper Brick can be found. If it is connected locally to USB then localhost and 4223 is correct. The UID value has to be changed to the UID of the connected Stepper Brick, which you can figure out using Brick Viewer:

HOST = 'localhost';
PORT = 4223;
UID = 'XYZ'; % Change to your UID

Now you're ready to test the examples.

Octave

As an example we will run the Stepper Brick configuration example. To do this open the octave_example_configuration.m file from the octave/examples/brick/stepper/ folder in Octave.

In the example HOST and PORT specify at which network address the Stepper Brick can be found. If it is connected locally to USB then localhost and 4223 is correct. The UID value has to be changed to the UID of the connected Stepper Brick, which you can figure out using Brick Viewer:

HOST = "localhost";
PORT = 4223;
UID = "XYZ"; % Change to your UID

Now you're ready to test the examples.

Function vs Script Files

The Octave examples are function files. To execute them directly from a terminal, they have to be extended to script files. Just add a call to the example function at the end of the example:

function octave_example_configuration()
    % ...
end

octave_example_configuration(); % Add this line

Known Problems

In Octave 3.8 the Invoke function throws an java.lang.UnsatisfiedLinkError exception. The Invoke function is allows to call Octave functions from Java. The bindings use this for callbacks. This means that you cannot use callbacks in Octave 3.8. A discussion on the Octave mailing list didn't come to a conclusion of fix for this yet. Because of this we recommend Octave 3.6 for now. This version is not affected by this problem and the bindings works without any problems.

API Reference and Examples

Links to the API reference for the IP Connection, Bricks and Bricklets as well as the examples from the ZIP file of the bindings are listed in the following table. Further project descriptions can be found in the Starter Kits section.

  API Examples
IP Connection API Examples
     
Bricks    
DC API Examples
IMU API Examples
IMU 2.0 API Examples
Master API Examples
RED API Examples
Servo API Examples
Silent Stepper API Examples
Stepper API Examples
     
Bricklets    
Accelerometer API Examples
Ambient Light API Examples
Ambient Light 2.0 API Examples
Analog In API Examples
Analog In 2.0 API Examples
Analog Out API Examples
Analog Out 2.0 API Examples
Barometer API Examples
CAN API Examples
CO2 API Examples
Color API Examples
Current12 API Examples
Current25 API Examples
Distance IR API Examples
Distance US API Examples
Dual Button API Examples
Dual Relay API Examples
Dust Detector API Examples
GPS API Examples
Hall Effect API Examples
Humidity API Examples
Industrial Analog Out API Examples
Industrial Digital In 4 API Examples
Industrial Digital Out 4 API Examples
Industrial Dual 0-20mA API Examples
Industrial Dual Analog In API Examples
Industrial Quad Relay API Examples
IO-16 API Examples
IO-4 API Examples
Joystick API Examples
Laser Range Finder API Examples
LCD 16x2 API Examples
LCD 20x4 API Examples
LED Strip API Examples
Line API Examples
Linear Poti API Examples
Load Cell API Examples
Moisture API Examples
Motion Detector API Examples
Multi Touch API Examples
NFC/RFID API Examples
OLED 128x64 API Examples
OLED 64x48 API Examples
Piezo Buzzer API Examples
Piezo Speaker API Examples
PTC API Examples
Real-Time Clock API Examples
Remote Switch API Examples
RGB LED API Examples
Rotary Encoder API Examples
Rotary Poti API Examples
RS232 API Examples
Segment Display 4x7 API Examples
Solid State Relay API Examples
Sound Intensity API Examples
Temperature API Examples
Temperature IR API Examples
Thermocouple API Examples
Tilt API Examples
UV Light API Examples
Voltage API Examples
Voltage/Current API Examples