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leJOS Features, News

A new release!

leJOS EV3 0.9.0-beta has been released, 8 months since the previous release. Was it worth the wait? Well let’s see what this release has to offer.


The leJOS EV3 Windows installer now supports both 32 an 64 bit versions of Java, 64 bit being the default. If you install the 64 bit system you might have to manually remove the previous version of leJOS EV3. Both Java 7 and 8 are supported.

On the brick Java 7 still is the default.

Installing leJOS EV3

The previous version of leJOS EV3 introduced the SD card installer. The installer made it possible to install leJOS from a Windows platform and was a major step forward in terms of user friendliness. This time we made the install process more robust. Both the SD card installer and the install script (that runs the first time you boot the brick from the SD card) are improved. You still have to make sure to “safely eject” the SD card after using the SD card installer.

Synchronizing motors

You can now synchronize motor commands to make sure motors start simultaneously our to get the encoder values from exactly the same time. This solves some of the timing issues we have seen on the EV3. You can read more about the problem and the solution in two previous posts. Our pilot, that suffered hard from timing problems on the EV3, is now accurate again.


The quality of audio playback has improved much. leJOS EV3 now also supports a greater variety of sample rates. You can hear the difference from the audio samples in this post that also explains how it was done.

Sensor ports

I2C sensors can now benefit from higher I2C speed if the sensor supports it. In high speed mode the data transfer rate is about 10 times faster than in default mode. The NXT ultrasonic sensor cannot benefit from this, but most third party sensors can.

There have been numerous bug fixes and improvements in the sensor ports. The RGB-mode of the EV3 color sensor now works as a result of it. Remote sensors work better.


Using sensors that support different modes is now easier. You now have two options to work with these kind of sensors. One is to use the sensor object to fetch samples from. You can switch to the mode of your choice using the setCurrentMode method of the sensor object. The other option is to get a SensorMode object from the sensor object and use this SensorMode object to fetch the samples from. The second option allows you to use different modes of the sensor concurrently. This is nicely demonstrated in the BumperCar example.

All the sensors now have JavaDoc informing you of the supported modes and providing links to the data sheets or product page of the sensor.

Webcam support

One of the more exiting features of this release is webcam support. You can now use a USB video class compatible webcam and process its images directly on the EV3. There are some blog posts about this feature that will help you going (1, 2, 3). I expect some cool examples of this coming from the community soon.

Remote access

leLOS EV3 now supports two ways to get remote access to the brick. The previous versions of leJOS EV3 supported RMI for remote access. leJOS EV3 now also supports remote requests. This gives access to the brick from platforms that do support Java but that do not support RMI, like for example android phones. There are some nice examples of this on the blog. You can even find the code for a complete android control app here. Remote requests only work over wifi.

Using leJOS EV3 0.9.0-beta you can publish samples using the publish filter and subscribe to it from any device supporting Java within the network. This allows you to remotely monitor your sensors. This feature is explained with an example in this blog post.

Bug fixes

There have been a lot of bug fixes. But there might still be some bugs crawling around that escaped our attention and new ones might have spawn. If you encounter one pleas notify us on the leJOS forum.


One thought on “A new release!

  1. “exciting” not “exiting”

    Posted by Rob | 2015/02/22, 12:28

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