Programming Lego Mindstorms NXT

When the program has been compiled, it is read and executed by the microcontrollers in the NXT brick. Further, the LEGO Mindstorms kit contains the parts and.
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It supports direct commands and several aftermarket sensors. Physical Etoys is a visual programming system for different electronic devices. It supports direct mode and compiled mode. The sensors come assembled and programmed. In the software see Programming above , people can decide what to do with the information that comes from the sensors, such as programming the robot move forward until it touches something. Lego also sells an adapter to the Vernier sensor product line.

Vernier produces data collection devices and related software for use in education. Sensors are connected to the NXT brick using a 6-position modular connector that features both analog and digital interfaces. The analog interface is backward-compatible using an adapter with the older Robotics Invention System.

The digital interface is capable of both I 2 C and RS communication.

Intro to NXT 2.0 Programming

Lego Mindstorms NXT 2. The set contains pieces, including a new sensor that can detect colors. Parts can be ordered separately. In the original kit, the sensors included are the color sensor, two touch sensors, and an ultrasonic sensor:. In order to create larger, more complex programs, programming software on a PC is required. The standard programming software is NXT-G, which is included in the package. Third-party programming software is also available, some of which is listed below:. NXT-G is the programming software included in the standard base kit.

It features an interactive drag-and-drop environment. Since its release, several bugs have been found and new sensors have been created. While the toolkit does allow for the creation of new sensors, National Instruments has yet to formally release an update. It requires nxtOSEK to run. RoboMind is an educational programming environment that offers a concise scripting language for programming a simulated robot.


  1. Navigation menu;
  2. LEGO Mindstorms NXT.
  3. Designer Evolution: A Transhumanist Manifesto.
  4. introduction to programming NXT Robots in C with RobotC - Génération Robots;

These internationalized scripts can, however, also directly be exported to Lego Mindstorms robots. It also has a component architecture UObject for distributed computation. Unlike the other languages for the NXT the code isn't compiled to a binary file. This method of execution is significantly slower than executing compiled code directly. Moreover, as we shall see below, RobotC installs its own firmware on the robot, firmware that is more efficient than the standard firmware. RobotC programs are the fastest when compared to programs created with other programming software.

By default, RobotC supports all the standard Lego sensors. A third-party open-source library is available and includes all the sensors and accessories found on the market. RobotC therefore provides unlimited programming of the NXT robot. A 3D simulation tool compatible with RobotC is currently being developed at Carnegie Mellon University this tool will be included in the version 3. The RobotC programming interface. The RobotC programming interface is conventional enough for anyone familiar with programming environments.

The left-hand bar is used to find the standard code structures, and the error zone at the bottom lists the compiler outputs. During programming, RobotC runs IntelliSense, which auto-completes terms entered by the programmer for increased efficiency and productivity. This only needs to be done once and is very easy. This opens a new window, shown below:. The message is very clear: You will hear the brick make a little noise and then reboot itself. Firmware downloaded on the NXT.

Introduction

If, after working with RobotC, you wish to work again with NXT-G the graphical programming software supplied with your Lego kit , you will need to repeat the same procedure in the NXT-G interface, which will revert to its original firmware. We are now ready for our first program. In this program, motors connected to ports A and C on your robot are controlled using the motor function.

The value assigned to this function indicates the speed at which the motor runs:. Depending on your construction the direction of the motor on your robot , you will have to use a positive or negative value. F5 compiles and transfers the compiled code to the robot. Naturally, this function only works if the robot is connected, i. All software necessary to work with Ada and NXT platform is installed on the Windows lab machines in the lab This includes software for flashing the firmware, compiling programs and uploading them.

Cygwin is a shell program which emulates Unix environment inside windows. In order to compile Ada NXT programs, all you need to do is to have an appropriate makefile in the current directory. It is recommended that you use a different subdirectory for each part of the assignment. For compiling use "make all" command. Compiler will compile all the required drivers and at the end will generate a compressed file with same name as the main procedure no extension in Windows, with.

In order to start with the lab, you first need to change a setting in the original firmware of the robot.

Now put it into reset mode by pressing the reset button at the back of the NXT, upper left corner beneath the USB connector for more than 5 seconds. The brick will start ticking shortly after. This means you robot is ready for uploading the code into its ram. In this lab, the robot will be always on "reset mode" when you upload a program as the code of the previous run can not reside in the ram after turning it off. The original firmware can be flashed back with the help of TA which you please do before handing back the box.

Successful upload will show something similar address may be different: Image started at 0xc. Now you can disconnect the robot and try testing it. You can turn off the robot by pressing the middle orange button. If you like to work at home, you can install the compilation and upload toolchain yourself.

Nine alternative programming languages for LEGO MINDSTORMS

Since this depends heavily on your setup, we can't give you any direct support. However, installation in Windows is farely simple and instructions for Windows and Linux installation can be found in instruction file. The program you will write is a simple "hello world! Priority'First ; begin Tasks. Note that we assigned lowest priority to this procedure by using attribute 'First which indicates the first value of a range.

This procedure is calling a procedure background the main procedure of Tasks of package Tasks. Your code should do the following:. Light sensors are bit tricky to initialize. Try different procedures of the nxt-display package to master output in the display. For more advanced kind of display you can use the nxt-display-concurrent package from facilities. Make sure your code compiles without error and executes as desired on the NXT brick. Try to measure light values of different surfaces light ones, dark ones, In this part, you will learn how to program event-driven schedules with NXT.

The target application will be a LEGO car that drives forward as long as you press a touch sensor and it senses a table underneath its wheels with the help of a light sensor. For this purpose, build a LEGO car that can drive on wheels. You may find inspiration in the manual included in the LEGO box. Further, connect a touch sensor using a standard sensor cable to one of the sensor inputs. Ideally events generated by external sources are detected by the interrupt service routines ISRs. This allows to react immediately to signals from various sources. Unfortunately, most of the sensors on the NXT are working in a polling mode: They need to be asked for their state again and again, instead of getting active themselves when something interesting happens.

Our workaround for this is to create a small, second task that and checks the sensors periodically about every 10ms. If the state of the sensor changed, it generates the appropriate event for us. Integer; -- Event data declaration Signalled: This protect object can be used by different tasks to communicate between them. For example, a task can block on receiving event:.

In order to do this, declare and implement a task "EventdispatcherTask".

Nine alternative programming languages for LEGO MINDSTORMS – LEGO Engineering

It should call the appropriate API function to read the touch sensor and compare it to it's old state. A static variable may be useful for that. If the state changed, it should release the corresponding event by using signal procedure of the Event protected object. Just as in part 1, put your code in an infinite loop with a delay in the end of the loop body. As suggested by the names of the events, the idea is that they should occur as soon as the user presses and releases the attached touch sensor.

In order for MotorcontrolTask to have priority over EventdispatcherTask, make sure to assign a lower priority to the latter. Otherwise, the infinite loop containing the sensor reading would just make the system completely busy and it could never react to the generated events. Add further some nice status output on the LCD. This should complete your basic event-driven program.

Compile and upload the program and try whether the car reacts to your commands. Attach a light sensor to your car that is attached somewhere in front of the wheel axis, close to the ground, pointing downwards. Extend the program to also react to this light sensor. The car should stop not only when the touch sensor is released, but also when the light sensor detects that the car is very close to the edge of a table.

You may need to play a little bit with the "Hello World! The car should only start moving again when the car is back on the table and the touch sensor is pressed again. The edge detection should happen in EventdispatcherTask and be communicated to MotorcontrolTask via the event protected object. Use two new events for that purpose. Make sure you define and use all events properly. Further, the display should provide some useful information about the state of the car. Please hand in only the source of the full second program that includes the light sensor code.

Make sure you include brief explanations and that your source is well-commented. Note that hand-ins without meaningful comments will be directly discarded. Real-time schedulers usually schedule most of their tasks periodically. This usually fits the applications: Sensor data needs to be read periodically and reactions in control loops are also calculated periodically and depend on a constant sampling period. Another advantage over purely event-driven scheduling is that the system becomes much more predictable, since load bursts are avoided and very sophisticated techniques exist to analyze periodic schedules.

You will learn about response-time analysis later during the course. The target application in this part will make your car keep a constant distance to some given object in front of it.