Thursday, February 21, 2008

My Lego Mindstorms Nxt kit


After a long research and lonnnngggg search, finally I got my Lego Mindstorms Nxt (LMN) robotics kit, last weekend. It was a long wait and I was frustrated by Walmart, Fry's Electronics guys. I picked up mine at a Lego retail store in Hillsdale mall. It costed me $260. Costly though. I am not sure, if you could get one in India.

I was evaluating a robotics kit for a long time, as I don't know much of mechanical or electronics to
design bots or construct circuit boards. My research took me to Lego Mindstorms Nxt kit, which is actually meant for 10+ years kids. But, it's okay. There are lot of guys out there working on their innovative ideas on the kit. Those ideas are fascinating.

Let's look at the stuffs that come with the package. The earlier edition of LMN was just called "Lego Mindstorms" and it is in retail no more.
  • The brain of this kit is the NXT brick, which runs 32-bit ARM7 micro-controller. More details later.
  • Three servo motors - for movements, arms or wheels.
  • Ultrasonic sensor - to measure distance to an object.
  • Light sensor - to detect light and color.
  • Sound sensor - to hear sound
  • Touch sensor - to feel the environment
  • 577 lego bricks, screws, etc etc for constructing robots.
The NXT brick has three output ports for motors and four input ports for sensors. The configuration for the NXT brick is as below:
  • 32-bit ARM7 microcontroller
  • 256 Kbytes FLASH, 64 Kbytes RAM
  • 8-bit AVR microcontroller
  • 4 Kbytes FLASH, 512 Byte RAM
  • Bluetooth wireless communication (Bluetooth Class II V2.0 compliant)
  • USB full speed port (12 Mbit/s)
  • 4 input ports, 6-wire cable digital platform (One port includes a IEC 61158 Type 4/EN 50 170 compliant expansion port for future use)
  • 3 output ports, 6-wire cable digital platform
  • 100 x 64 pixel LCD graphical display
  • Loudspeaker - 8 kHz sound quality. Sound channel with 8-bit resolution and 2-16 KHz sample rate.
  • Power source: 6 AA batteries
Now, let us look at the programming environment that comes with the kit. Since the kit was designed for 10+ age group, Lego decided to go with a GUI based programming. The language is called NXT-G. It has a collection of what is called blocks and a number of required blocks are connected together to accomplish a task.

But, it does not stop here. If you are looking for a programming environment similar to C, you are not the first one to think about it. There are pretty good number of development environments/languages that closely resembles ANSI C standards. The widely used OS for NXT kit is LEJOS, a tiny Java VM.

Though I am ready to start my work on this, I am waiting for my current assignments (job) to come to a stop. So that, I would get more time to work on this.

NXT blog: About various languages available for NXT kit.

Pictures are available at

Have fun!!!