Category: Robots

NXT Alpha Rex: avoiding obstacles

I built NXT Alpha Rex and I tested two applications from next two links:
Both work very well.

To dowload a short video click on this link:

The NXC application (that use BTlib.nxc made by Daniele Benedettelli) is a sample to test NXT motors/sensors/buttons/display/bluetooth
(default ports connection) features.
To test a remote control via bluetooth you can use the C# application included.
Steps tu uses both (C# and NXC) applications together:
1) Turn on NXT.
2) Run C# application and click connect.
3) Wait until connection is active.
4) Run NXT application (FeaturesTest1.nxc).
Download source code:
This time the NXT robot try to follow a path on the same route used with RCX robot.

Second pic shows a custum block example. Using blocks can make the projects more short and nice .

First tests with Lego NXT

The first NXT robot I built it’s about the same that paper manual show.
I added a touch sensor on the arm, I raised ultrasonic sensor (now it work better). I maked also some other little changes too.
Here the connections list:



Arm Motor


Right Wheel Motor


Left Wheel Motor


Touch Sensor


Audio Sensor (Microphone)


Forward Light Sensor


Ultrasonic Sensor (Distance)
The first program (pic 2) simply read light sensor (other version read also the ultrasonic) to show on display.
The second program (pic 1, but use this link to see it better:, after an audio command, make robot advances until it’s near to the ball, then it try to center on it (to see better its color), then it try to hit the ball.
You can also see the movie of second program:
I started to make some experiments with Lego Mindstorm RCX, to make some lessons for my school students.
I use leJOS plugin for Eclipse to work with Java.
To see an example:
To see a movie about path finding RCX robot: