Skip to main content

Remotely controlling NXT robots using leJOS NXJ

For a project where multiple NXT bricks need to be remotely controlled by a single remote control, I decided to build that control with LEGO® MINDSTORMS NXT also, so that one (master) brick would control three other (slave) bricks wirelessly using Bluetooth.
From earlier projects I knew how laborious the programming of something like that is apt to become, in particular with NXT-G; so this time, I decided to use leJOS NXJ, the Java platform for the NXT.
Still, I expected to have to invest quite some amount of time with writing a lot of complex program code, both for the master brick and the three slave NXT bricks.

But far from it!
I'm still quite out of my mind how incredibly ease such a task has become when using the RemoteNXT class that comes with the most previous release 0.9 of leJOS NXJ!
One (!) single line of code, and your master NXT is connected to a remote NXT:

RemoteNXT remoteNXT1 = new NXTRemote("NameOfARemoteNXT",Bluetooth.getConnector().

You do need even have to manually pair the two bricks!
From that point on in your program, you have access to all motors and sensors of the remotely controlled bricks (same as if they were directly plugged into your own remote control brick*); for instance, to run motor A on the remote brick, just call


One can use up to three remote bricks that way at the same time in one single master program.

Now, that's what I call a programming tool for the NXT!
Well done, leJOS guys!  

*Actually, sort of: in the current release, you cannot use all the methods remotely that you have at your disposal in the local context, just the simple ones like forward(), backward and setSpeed()

Popular posts from this blog


2023 is the 25th Anniversary of the MINDSTORMS brand. For 25 years, MINDSTORMS has educated and inspired a generation of robot builders, both children and adults. Unfortunately, the LEGO Group decided to end the line on December 2022. Many ROBOTMAK3RS have been passionately involved with the development of MINDSTORMS through the MUP and MCP programs. Even with the newest Robot Inventor line, several ROBOTMAK3RS were invited to submit additional bonus models that were included in the official app. Regardless of the retirement of a major LEGO robotics product line, ROBOTMAK3RS continue to MAKE-SHARE-INSPIRE using all LEGO robotics platforms available to us. Here is the official statement from LEGO. Since its launch in September 1998, LEGO MINDSTORMS has been one of the core ‘Build & Code’ experiences in the company’s portfolio, carrying with it significant brand equity and becoming a stand-out experience for the early days of consumer robotics and leading to current Build & Code

Celebrating MINDSTORMS with a Remix Part 1

In honor of the 25th Anniversary of MINDSTORMS, we asked ROBOTMAK3RS to combine a LEGO set of their choice with a MINDSTORMS set. Here is what these five ROBOTMAK3RS came up with.  MINDSTORMS Chess Assistant by Arvind Seshan Overview: When you are new to chess, it can be a challenge to remember which pieces go where. Now, you can use machine learning and LEGO MINDSTORMS Robot Inventor to build a tool to help you learn where all the chess pieces go on the chess board. Sets used: LEGO® Iconic Chess Set (40174) and MINDSTORMS Robot Inventor (51515) Review: I really like how the chess set base can store all the pieces underneath and that the board neatly splits in half for handy storage. The chess pieces themselves are very sturdy and well built. My only criticism is the building of the box itself. It was quite difficult to see what pieces to use and since the entire box is made mostly of thin plates, it took a lot of time and patience. I would have liked the storage area to be sliding dra

Machine Learning Meets MINDSTORMS

Machine Learning Extension LEGO MINDSTORMS announced today a brand new feature that is sure to excite all users. Machine Learning Extension is coming to the software in August 2022. This will allow users to implement new applications that were not possible before. Machine Learning has become exceedingly popular in recent years with applications in all sorts of industries from robotics to financial services to climate change. Now, even the youngest of robot enthusiasts and programmers have access to the world of Machine Learning and Artificial Intelligence. Comparing two classes Machine Learning on MINDSTORMS will work with both images and audio. For instance, you could train your model to recognize smiles and frowns on your face and have the emotion displayed on your hub. You could train your model to recognize when a red ball is present or not or identify a particular LEGO element. You can control your robot with audio commands that use your own voice. It is exciting to see what new p