Skip to main content

Inside the NXT brick: lots of microcontrollers

The NXT actually has 3 microcontrollers making everything tick along.

(1) The little circuit board at the top of the picture is the Bluetooth to serial module. The left most, rectangular chip is the memory with the Bluetooth control software from Cambridge Silicon Radio. The square chip is the CSR Bluecore 4 microcontroller and radio hardware BC417143BQN, supporting Bluetooth v2.0 and EDR. The gold zig-zag trace at the top right hand corner is presumably the antenna.

(2) The main 32-bit ARM controller that runs your programs, an Atmel AT91SAM7S256. This includes Flash memory/file system, RAM and the USB Device interface.

(3) An 8-bit Atmel ATMEGA48. I presume this manages the pulse width modulation (PWM) of the motors, and uses the feedback from the NXT motor rotation sensors to tune the power to each motor.

Correction, courtesy of J├╝rgen Stuber: the ATmega48 drives the PWM for the motor control, but the rotation sensors feedback to the AT91SAM7s256.

In other words if you set two NXT motors, (e.g. on the left and right sides of a vehicle), to the same power level this controller will try to make both motors turn at the same rate. A notoriously difficult to solve problem in user level programs on the RCX.


Popular posts from this blog

Celebrating MINDSTORMS with a Remix - Part 2

The ROBOTMAK3RS continued their celebration of the 25th Anniversary of MINDSTORMS through these summer and fall remix projects. Each ROBOTMAK3R was tasked with selecting one LEGO set of their choice and combining it with a MINDSTORMS set. Below are the five amazing models they came up with. Remote controlled material handle r by Jozua van Ravenhorst (aka Mr Jo) This remix combines the LEGO Technic Material Handler (42144) with MINDSTORMS EV3 (31313) It uses the power of pneumatic cylinders to move objects around. By using a bluetooth remote control, very precise movements can be made with this model. Touch sensors in the base chassis prevent the turret twisting the cables that go through the turntable to much. The program has several protections to prevent over pressurizing the system for each of the 3 individual pumps and valves that control the 2 booms and claws. The real version of this machine is mostly used in waste material sites to bring the material to machines that sort and


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 25 Years of MINDSTORMS

In celebration of the 25th Anniversary of MINDSTORMS, we take a trip through history. Please also visit ROBOTMAK3RS Community every week as we highlight different projects all through 2023 in celebration of the anniversary. Some of the early history is based on the content shared by  Coder Shah  in our  MINDSTORMS EV3 Community Group . Some of the text and links may have been edited from his original posts for consistency and clarity.  1984 - Kjeld Kirk Kristiansen watched a TV program called "Talking Turtle," where MIT professor Seymour Papert demonstrated how children could control robot "turtles" using LOGO, a programming language he developed. 1988 - The collaboration between MIT and LEGO resulted in LEGO TC Logo in 1988, which allowed students to control LEGO models using computer commands. The video shows Papert demonstrating TC Logo. 1990 - LEGO TC Logo was hampered since the robots you built had to be tethered to a personal computer. LEGO and MIT