[LeJOS] Let's program mindstorm-EV3 in Java [Environment construction first part]
Overview
With EV3, you can challenge embedded programming of robots in Java! leJOS is a system for controlling mindstorm-EV3 in Java. You can easily enjoy controlling EV3 with Java by installing a dedicated OS on EV3. In this article, I will explain how to build an environment in two parts, the first part and the second part. In the first part, we will explain how to install LeJOS on the intelligent block itself.
environment
- mindstorm-EV3
- PC : MacBook OS X
Things necessary
- LEGO mindstorm-EV3 --USB dongle BUFFALO WLI-UC-GNM2 --microSD card Verbatim SDHC8GYVB1
Please use your own USB dongle and microSD card.
leJOS installation procedure
download leJOS
https://sourceforge.net/projects/ev3.lejos.p/files/ Download the latest leJOS_EV3_0.9.1-beta.tar.gz from the URL and unzip it.
When unzipped, the file structure should look like this.
Write image file to microSD card
If you unzip sd500.zip in the previous file, the image file sd500.img will appear. Write this to the microSD card. I used Etcher for writing.
Save necessary files to microSD card
Unzip lejosimage.zip in the file where you unzipped leJOS_EV3_0.9.1-beta.tar.gz earlier. Move to the unzipped folder and save all these files in the root directory of the microSD card.
Next, download Java for lejos from the Oracle JRE (URL below). http://www.oracle.com/technetwork/java/embedded/downloads/javase/javaseemeddedev3-1982511.html
Account registration is required to download. Save the downloaded file (ejre-7u60-b19-ejre-7u60-fcs-b19-linux-arm-sflt-headless-07_may_2014.tar.gz) to the root directory of the microSD card without decompressing it.
At this point, the file structure of the microSD card should look like this.
Start-up
Insert the SD card into EV3 and start it. At first, it takes time to install the module, so it will start after about 10 minutes.
Startup screen
WiFi settings
Let's connect leJOS to the network. Insert the USB dongle into the EV3 main unit and select the WiFi button on the screen. If you enter the SSID of the network according to the GUI, you will be connected to the network and the IP address will be displayed.
The IP address (192.168.2.91) is displayed.
SSH connection
$ ssh [email protected]
[email protected]'s password:
root@EV3:~#
No password is set by default. Please replace the IP address with your own environment
Summary
leJOS includes some sample code by default. It will be interesting to select Samples on the screen and try various things. Building an environment is not so difficult, so please give it a try.
reference
https://sourceforge.net/p/etroboev3/wiki/lejosev3_mac_eclipse_section02/
https://sourceforge.net/p/lejos/wiki/Installing%20leJOS/
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