building a development environment

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To develop components that run on EV3 and ev3dev, there are two approaches: developing directly on the EV3 or using a cross-development environment.

However, since the EV3 has only 64 MB of memory and a CPU clock speed of approximately 300 MHz, it is quite slow by today’s development standards. As a result, development directly on the EV3 can be rather challenging.

Cross-development refers to creating executable files for a different architecture (such as ARM) on a general-purpose PC architecture such as Intel CPUs.

Although cross-development does not allow the compile-and-run workflow available on the target system itself, compilation is dramatically faster, resulting in higher overall development efficiency.

Installing Ubuntu

The development environment uses Ubuntu (14.04 LTS), one of the Linux distributions.

Download the ISO image from the above URL and install the operating system.

You may install it directly on your PC or use it within a virtual machine.

Common virtual machine environments include:

For detailed usage instructions, please refer to each product’s website or search for online tutorials.

brickstrap

From this point onward, it is assumed that Ubuntu 14.04 has already been installed.

First, install a tool called brickstrap. Although brickstrap is primarily used to create ev3dev OS images, it can also be used as a cross-development tool.

Installing brickstrap

brickstrap is developed on the following GitHub repository.

First, install brickstrap. Since it is not available in the standard Debian repositories, the ev3dev.org package repository must be added.


$ sudo apt-key adv --keyserver pgp.mit.edu --recv-keys 2B210565

<!-- $ sudo apt-add-repository http://ev3dev.org/debian -->

$ sudo apt-add-repository "deb http://archive.ev3dev.org/ubuntu trusty main"
$ sudo apt-get update
$ sudo apt-get install brickstrap

Preparing for Image Creation

First, execute the following commands to create a supermin appliance.


$ sudo update-guestfs-appliance
$ sudo usermod -a -G kvm <username>
$ sudo chmod +r /boot/vmlinuz*

Creating the Development Environment

Once the preparation is complete, create the development environment.

A simulated filesystem corresponding to the EV3 target system will be created in a specified directory. A suitable location is somewhere under your home directory. In this example, a directory named work is created under the home directory.


$ cd ~
$ mkdir work
$ cd work

Create the filesystem and image using the following command:


$ brickstrap -b ev3-ev3dev-jessie -d ev3-ev3dev-work all

This command takes approximately 10–20 minutes to complete.

What actually happens is that the commands, packages, and files required for the ev3dev Linux system are installed into a virtual root directory named ev3-ev3dev-work, and then assembled into an image file that can be written to an SD card.

When the process completes, you should find the files ev3-ev3dev-work.tar and ev3-ev3dev-work.img.

Writing the .img file to an SD card allows ev3dev to boot on the EV3.

Replacing proot

On Ubuntu 14.04 x86_64, the version of proot used internally by brickstrap is outdated and cannot execute certain functions related to user IDs and group IDs, causing apt-get errors.

To avoid this issue, use proot version 4.0 or later.

Download the x86_64 binary and copy it to your machine.


$ wget http://portable.proot.me/proot-x86_64
$ sudo mv /usr/bin/proot /usr/bin/proot_3.0.2
& sudo mv proot /usr/bin/
$ chmod 755 /usr/bin/proot

Starting the Shell

The cross-development environment is now ready.

Next, OpenRTM-aist can be compiled and installed, and RT Components can be developed.

brickstrap provides a mode that behaves as though packages are being installed and source code is being compiled directly on the EV3.

Run the following command:


user@host:`/work$` brickstrap -b ev3-ev3dev-jessie -d ev3-ev3dev-work shell

The command prompt will change to #, indicating that you are now in the simulated EV3 environment.

Compiling OpenRTM-aist

If you wish to compile and install OpenRTM-aist yourself, follow the steps below.

If you plan to use prebuilt packages instead, skip to the next section.

First, install the packages required to build OpenRTM-aist.


# apt-get update

# apt-get install libomniorb4-dev omniidl

# apt-get install gcc g++ make uuid-dev libboost-filesystem-dev

# apt-get install doxygen

# apt-get install build-essential debhelper devscripts

# apt-get install subversion texlive texlive-lang-cjk xdvik-ja python-yaml

# apt-get install wget

Next, download the OpenRTM-aist source code.


# cd /home

# wget http://tmp.openrtm.org/pub/OpenRTM-aist/cxx/x.y.z/OpenRTM-aist-x.y.z.tar.gz

# tar xvzf OpenRTM-aist-x.y.z.tar.gz

# cd OpenRTM-aist

# ./configure --prefix=/usr

# cd packages

# make

This generates OpenRTM-aist packages under the packages directory.

Install them as follows:


# dpkg -i openrtm-aist-*

Similarly, download and package OpenRTM-aist-Python.


# wget http://tmp.openrtm.org/pub/OpenRTM-aist/python/x.y.z/OpenRTM-aist-Python-x.y.z-RELEASE.zip

# cd OpenRTM-aist-Python

# cd packages

# make

Packages will be generated in the packages directory.

Install them as follows:


# dpkg -i openrtm-aist-python-*

Installing OpenRTM-aist

Instead of compiling OpenRTM-aist from source as described above, you may install prebuilt packages.

The procedure is almost identical to installing OpenRTM-aist directly on ev3dev.

Editing sources.list

Edit /etc/apt/sources.list to add openrtm.org as a package repository.


# vi /etc/apt/sources.list

Open the file and add the following line:


deb http://ftp.debian.org/debian jessie main contrib non-free
deb http://ev3dev.org/debian jessie main
deb http://openrtm.org/pub/Linux/debian jessie main ← Add this line

As shown above, add the OpenRTM repository at the end of the file.

Then update the package database:


# apt-get update

Since the EV3 is relatively slow, updating the package database may take a considerable amount of time.

Installing OpenRTM-aist Packages

Once the OpenRTM package repository is available, install the packages as follows:


# apt-get install openrtm-aist openrtm-aist-dev openrtm-aist-example

# apt-get install openrtm-aist-python openrtm-aist-python-example