preparing the sd card
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Introduction
This section explains how to install the runtime environment required to run OpenRTM-aist and its components on LEGO Mindstorms EV3.
Here, we will explain how to download the OS image provided by openrtm.org that includes OpenRTM-aist and perform the necessary setup.
The overall procedure for enabling OpenRTM on EV3 is as follows:
- Write the OS image to an SD card
- Perform basic OS setup
- Test execution of components
SD Card
The EV3 has one micro SD card slot. By inserting a micro SD card containing a bootable OS, you can start the EV3 with an arbitrary operating system.
The SD card must be a micro SD card with a capacity between 2 GB and 32 GB. Please note that mini SD cards and standard SD cards cannot be inserted.
The image file is approximately 2 GB in size, so at least 2 GB of capacity is required. EV3 does not support SDXC cards larger than 32 GB.
- Required SD Card
- micro SD card
- 2 GB or larger, up to 32 GB
Downloading the OS Image
To run OpenRTM-aist on EV3, an operating system called ev3dev is used.
- ev3dev Website: http://www.ev3dev.org
Download ev3-ev3dev-jessie-2015-12-30.img.zip from the following site.
There are many similarly named files available, so be careful to download the correct one.
- https://github.com/ev3dev/ev3dev/releases
Downloading the ev3dev OS Image
ev3dev is a Debian GNU/Linux distribution for EV3.
To run OpenRTM-aist, write ev3dev to a micro SD card and boot EV3 from that SD card.
Although the ev3dev OS image can be downloaded from the official website, it does not include OpenRTM-aist.
In most cases, download the ev3dev image containing OpenRTM-aist (C++ and Python) from the following link.
Image with Sample Components
This image includes sample components such as Educator Vehicle.
If the wireless LAN access point mode does not work correctly after replacing the EV3 wireless LAN adapter, connect to another access point and edit 70-persistent-net.rules using the following command.
Log in with username robot and password maker.
sudo nano /etc/udev/rules.d/70-persistent-net.rules
Specifically, comment out all lines beginning with SUBSYSTEM in 70-persistent-net.rules.
# USB device 0x:0x (rtl8192cu)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:22:cf:f6:52:a5", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan1"
Extracting the Image
Extract the downloaded file YYYY-MM-DD-ev3dev-openrtm.zip.
A file named YYYY-MM-DD-ev3dev-openrtm.img of approximately 2 GB should be extracted.
Windows
Right-click the file and select Extract All.
Linux
$ unzip <image file>
If the unzip command is not installed, install it first.
$ unzip 2015-08-06-ev3dev-openrtm.zip
Archive: 2015-08-06-ev3dev-openrtm.zip
inflating: 2015-08-06-ev3dev-openrtm.img
$ ls -l
total 2321300
-rw-rw-r-- 1 n-ando n-ando 1887436800 Aug 4 21:37 2015-08-06-ev3dev-openrtm.img
-rw-rw-r-- 1 n-ando n-ando 489565916 Aug 5 10:13 2015-08-06-ev3dev-openrtm.zip
If extraction fails, the downloaded file may be corrupted. Delete the damaged file and download it again.
Writing the Image
The extracted file yyyy-mm-dd-ev3dev-openrtm.img is a disk image file containing a byte-for-byte copy of the bootable disk.
Simply copying this file to the SD card will NOT work!
Write the image to the SD card using one of the methods described below.
Writing the Image (Windows)
On Windows, you can use Win32DiskImager to write the image.
Download the binary package from:
- Win32DiskImager: http://sourceforge.jp/projects/sfnet_win32diskimager/
Extract the downloaded archive (win32diskimager-vX.X-binary.zip).
Win32DiskImager does not support double-byte characters. Extract the image file to a location whose path contains no non-ASCII characters or spaces.
Insert the SD card into the PC and start Win32DiskImager.
The SD card must be recognized as a drive. Format it as FAT32 beforehand.
Select the extracted image file (YYYY-MM-DD-ev3dev-openrtm.img) in Image File, choose the SD card drive in Drive, and click Write.
The SD card is now ready.
After writing is complete, insert the SD card into the EV3 and power it on.
Writing the Image (Linux)
On Linux, use the dd command.
The dd command is installed by default on most UNIX-like systems.
Insert the SD card and identify the device name using:
$ dmesg
Example:
[333478.822170] sd 3:0:0:0: [sdb] Assuming drive cache: write through
[333478.822174] sdb: sdb1 sdb2
[333478.839563] sd 3:0:0:0: [sdb] Assuming drive cache: write through
[333478.839567] sd 3:0:0:0: [sdb] Attached SCSI removable disk
In this example, the SD card device appears to be sdb.
Check under /dev:
ls -al /dev/sd*
Never touch /dev/sda, as it is usually the system disk.
Some distributions automatically mount SD card partitions. If so, unmount them before writing.
Write the image:
$ sudo dd if=2015-08-05-ev3dev-openrtm.img of=/dev/sdb bs=1M
You can monitor progress using iostat.
$ iostat -mx 1
If write speeds are around 6 MB/s for a Class 6 card or 10 MB/s for a Class 10 card, the process is working normally.
After completion, unmount the card if it is automatically mounted and remove it safely.
Writing the Image (Mac OS X)
Mac OS X also uses the dd command.
However, the SD card is automatically mounted when inserted, so it must first be unmounted.
Locate the SD card in Finder and note its volume name (e.g., Untitled).
Use:
$ df -k
Find the mounted SD card, for example:
/dev/disk1s1 ... /Volumes/Untitled
Unmount it:
$ diskutil umount /Volumes/Untitled
Then write the image:
$ sudo dd if=2015-08-05-ev3dev-openrtm.img of=/dev/rdisk1 bs=1m
Here, /dev/rdisk1 is derived from /dev/disk1s1 by removing s1 and adding the r prefix.
Example output:
$ sudo dd if=2015-08-05-ev3dev-openrtm.img of=/dev/rdisk1 bs=1m
1850+0 records in
1850+0 records out
1939865600 bytes transferred in 302.377337 secs (6415380 bytes/sec)
$
You can monitor write activity using Activity Monitor.
If the write speed is approximately 6 MB/s for a Class 6 card or 10 MB/s for a Class 10 card, writing is proceeding normally.
After writing completes, the SD card will be automatically remounted. This time, use Finder’s eject button and remove the SD card safely.