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

remoteNXT1.A.forward();

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()

Another way of using the Power Functions remote handset to control the NXT

Philo, author of many a NXT LDraw part and renowned expert of NXT electronics, has published an artcle on his web site on another possibility of using the Power Functions remote handset to control a NXT. In contrast to other already existing solutions to do this (e.g. Dave Parker's or Mike Brandl's), Philo's one allows for using all nine different combinations of the PF handset:

"The idea is simple: combine the outputs of the PF receiver with well chosen resistor values to obtain a different voltage for each combination of controls and measure this voltage with the NXT."

Yet, you need to do some soldering inside of the PF receiver for that.

Minimalistic remote control for the NXT

When using Philo's great NXT joystick remote control for my basketball-playing NXT robots at Fana'Briques in June, I noticed that the very young users had some difficulties in getting along with it (in particular due to the size and the problems they had with understanding how to manage turns). So for the SteinCHenwelt LEGO® event ten days ago, I decided to come up with a more simplified one that met the reduced requirements of my soccer robots that debuted there.
The result was the rather minimalistic Remote Control No 3, a Bluetooth-based NXT remote control that uses the four buttons on the NXT Brick itself to control the movement of a remote NXT robot (forward, backward, left, right).
The two attached touch sensors can be optionally used to trigger special functions on the controlled robot (in the case of the soccer robots, it was kicking the ball).

At SteinCHenwelt, the gamepad-oriented style of the remote control and its comparatively small size went down well with the youngsters (you can see its usage in the SteinCHenwelt movie).

Remote Control No 3 is a good option when you do not need to control the actual speed of the remote robot. For the SteinCHenwelt, I programmed it with leJOS NXJ, the Java platform for the NXT (the programs can be downloaded from the associated page at my NXT web site); however, writing NXT-G programs for it should not be that difficult, also.

More information on NXT 2.0

This is the parts list inventory of the new set. Notice that the set also includes 4 wheels with tyres, even though the latter parts are not used in any of the set models.
The box includes more smaller beams than the old set, and the amount of length-15 beams is reduced to 2. However, you get a lot of other useful beams in return. Apart from new parts, some of the older parts have a different color.

















Here's a more detailed picture of the back side of the box. Two new features of the software are shown here: Remote control (USB or BlueTooth) and the possibility to create custom sounds and image files for the NXT.

The box also promises 10 models with downloadable building instructions from mindstorms.com upon the set's release. Two of the models are shown here. One of them is a six legged Mantis, and the other one is a cool transforming robot.
















This image is not very new, but it shows the color sensor functionality, with three separate functions:
- It can be used in Color Sensor Mode. Using the standard software, it can detect six color: black, white, red, green, blue and yellow
- It can be used in Lamp mode: It is possible to control the colored LED on the sensor, by setting it to either green, red or blue. In this mode, the light intensity would be just around the same brightness of the old Light Sensor.
- It can be used in Light Sensor Mode. In this mode, it acts just like the old light sensor: it returns a value from 0-100 where 0 is darkest, and 100 is brightest. In this mode, it is also possible to pick a desired LED color (again, red, blue or green).

(Information from the Junior Mindstorms Developer Program, JMDP)

INXT - Control the NXT from an IPHONE or IPOD

Daniel Siemer made a NXT remote for the IPHONE. It uses the same principle as my network-server which means that you can control the NXT from anywhere in the world by sending commands to a server running on a PC. Daniel wrote a server for MAC OS called OSX server. INXT can be use with either the MAC OS versrion or my Windows version. The servers are free but you need to buy the IPHONE remote though ITunes by following this link; the remote is 4.99 USD. You will find the support site here, if you need help to set up either the windows or MAC OS server. It looks really cool great job.

NXT Wheel: remote control for mobile robots

Remember the NXT Switchboard, the NXT-based remote control I posted some weeks ago about? It allows you to remotely control each motor of a NXT robot independently. However, it turned out that it's better suited for immobile robots as it's usually pretty difficult to actually steer a mobile robot when you need to control each of the driving motors on your own.
So I decided to create another remote control particularly aimed at such car-like mobile robots, called NXT Wheel; as a consequence, it has a large hand wheel and a speed throttle:

The response time is somewhat low, though...

Robot Inspiration Series #14: Remote Controlled Robot

This week's inspiration is to build a robot that can be controlled by a human. Although remote controlled robots may seem relatively easy to program and perhaps build, they don't have to be. Building and programming the remote control system can be a big challenge by itself. In addition, a robot that is remote controlled can still have many autonomous functions so that the driver doesn't have too many things to keep track of. For example, since I'm competing in FTC, a competition involving remote controlled robots part of the time, I'm constantly looking for ways to program my team's robot to either help the driver or take care of functions entirely so that the driver doesn't need to worry about it.

One fun application of remote controlled robots is a Battle Bots game, where multiple robots try to flip or disable their opponents. Once I made a remote controlled robot to battle with some of my siblings' Spybots. Racing is another possible application of remote controlled robots. If you have a wireless camera to attach to your robot, you could make a robotic explorer that would let you explore a room while sitting at your computer.

Some robots you can use for inspiration include my PC-Controlled Robot, Jim's remote controlled robot with camera goggles, and Philo's Spy Camera Rover along with his NXT Joystick. There's lots of others out there, and feel free to comment with any good ones you know of!

-Jonathan

NXT controlled motorcycle – with realistic steering!

A German builder named leggor has created a remote control for his NXT fatboy motorcyle.  That by itself isn’t anything new.  Many folks have created remote controls for their NXT projects.

What is neat about this remote control… is it simulates a real motorcycle handlebar.  Complete with twistable throttle and a break.

A simple shot of the controller:

 

Here is a short video of the bike and control in action:

 

Thanks to Klocki for the heads-up on this project. There are some other neat projects on leggor’s BrickShelf page.