LEGO IGT Compilation

NXT_USB is a C++ library used to control a LEGO Mindstorms NXT robot over a USB connection.

This code was modified from:

• NXT++: http://nxtpp.sourceforge.net
• Device::USB: http://search.cpan.org/~gwadej/Device-USB-0.21

Linux Installation

Reqirements

1. This code can be used only on a Linux distribution with root access. Remember to run any software utilizing this code as root.
2. libusb: http://libusb.sourceforge.net/

Instructions

Download libusb from:

 http://libusb.sourceforge.net (version 0.1.12)

Then run:

 tar zxvf libusb-0.1.12.tar.gz
 cd libusb-0.1.12/
 ./configure CFLAGS=-funsigned-char --prefix=<your libusb directory> --exec-prefix=<your libsub directory>
 make
 make install

Then add the libusb directory to your $LD_LIBRARY_PATH variable. Note that the INSTALL.libusb file has information about the installation process.

Another alternative is to use CMake:

 SET(CMAKE_CXX_FLAGS
   "-funsigned-char"
 )

 INCLUDE_DIRECTORIES(
   ...
   <your libusb directory (can be a relative path)>
 )

 ADD_LIBRARY(<your library name>
   ...
   NXT_USB.cxx
   NXT_USB_linux.cxx
 )

 FIND_LIBRARY(LIBUSB_LIB
   NAMES libusb-lib
   PATHS
    <your libusb directory (can be a relative path)>/lib
 )

 TARGET_LINK_LIBRARIES(Lego
   ...
   <your libusb directory (should be an absolute path)>/lib/libusb.so
 )

The simplest way to use this library is to keep the four NXT_USB files (NXT_USB.h, NXT_USB.cxx, NXT_USB_linux.h, and NXT_USB_linux.cxx) in the same directory as your program. Simply #include "NXT_USB.h" and compile as usual.

Windows Installation

The Windows installation of the NXT_USB requires the windows port of libusb using libusb-win32 open-source project.

1. Download from SourceForge
2. Install libusb-win32-filter-bin-0.1.12.1.exe by following the instructions
3. Download libusb-win32-device-bin-0.1.12.1.tar.gz from SourceForge
4. Extract libusb-win32-device-bin-0.1.12.1.tar.gz using winrar or cygwin (tar -zxf)
5. Plug the USB cable to your computer and start the Lego NXT
6. Go to 'Start Menu'->'Programs'->'LibUSB-Win32'->'Test Program', you should see the NXT device:

 bus-0/\\.\libusb0-0005--0x0694-0x0002     0694/0002
 Serial Number: 00165304BDE2
 wTotalLength:         32
 bNumInterfaces:       1
 bConfigurationValue:  1
 iConfiguration:       0
 bmAttributes:         c0h
 MaxPower:             0
   bInterfaceNumber:   0
   bAlternateSetting:  0
   bNumEndpoints:      2
   bInterfaceClass:    255
   bInterfaceSubClass: 255
   bInterfaceProtocol: 255
   iInterface:         0
     bEndpointAddress: 01h
     bmAttributes:     02h
     wMaxPacketSize:   64
     bInterval:        0
     bRefresh:         0
     bSynchAddress:    0
     bEndpointAddress: 82h
     bmAttributes:     02h
     wMaxPacketSize:   64
     bInterval:        0
     bRefresh:         0
     bSynchAddress:    0

Contact information

I would be more than happy to reply to any questions and comments emailed to dpace [at] bwh.harvard.edu.