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Brainstorming & Further Concepts


  • (./) Try using a different firmware than official standard NXT, like LeJOS / NXC / RobotC? There are hints to more precise motor control (TachoLimit problem potentially fixed in LeJOS) or better performance of direct commands / bluetooth transmission!


  • (!) Check the MATLAB-Help for the command readasync. Can it help to reduce timeouts and lags? Can it be used for the above mentioned non-blocking functions?


  • (./) Add USB-Support, try to use as many existing BT-functions as possible (by using wrappers if necessary). Some code snippets, hints etc are collected on this temporary page: USBStuff


  • {*} (!) {*} Consider Bluetooth / serial port code from MathWorks' NXT toolbox to reduce Bluetooth timeouts (try using option NumRetries?)
  • (./) The (sometimes optionally) passed Bluetooth-Handle (to functions) gets checked/validated far too often inside these functions. Checking/validating is only necessary at the lowest level, the other checks are a waste of performance…
  • (./) Compatibility for multiple bluetooth handles / NXT connections at one time is not perfectly implemented: The settings SendSendPause etc. are unique and global, and should be defined PER connection, not only once. Workaround: Disable those pauses by setting to 0.

Motor Control

  • (./) Note: Apparently we CAN access the PID regulation directly, as this post suggests (http://forums.nxtasy.org/index.php?showtopic=2054&view=findpost&p=16463). Code-Sample:
    def set_PID(motor,P,I,D):
        """Change the PID parameters 
    		>>> set_PID(motor,"\x78","\x78","\x78")    Use only hexadecimal number in string !"""
  • (./) Note: John Hansen supported the module ids at http://news.lugnet.com/robotics/nxt/nxthacking/?n=14 to access the module directly, without request sequentially the modules
    The interpretation should be MSB PP TT CC FF LSB —> 0xPPTTCCFF
    PP: identify programmer TT: module type identification CC and FF: module version identification
    The module IDs are:
    CommandModuleID  = 0x00010001
    OutputModuleID   = 0x00020001
    InputModuleID    = 0x00030001
    ButtonModuleID   = 0x00040001
    CommModuleID     = 0x00050001
    IOCtrlModuleID   = 0x00060001
    SoundModuleID    = 0x00080001
    LoaderModuleID   = 0x00090001
    DisplayModuleID  = 0x000A0001
    LowSpeedModuleID = 0x000B0001
    UIModuleID       = 0x000C0001
    /!\ As long as a new firmware update doesn't change this IDs, we are fine to use constants.
  • (./) Own tests and example programs "DriveAlong" using the NXT-G software showed no different behaviour of the driving robot. The motors also switch into the coast mode after the defined rotation angle is set.

Software Design

  • {X} Split GET-Functions into REQUEST and COLLECT parts again, making it possible to do calculations inbetween. I.e. add possibility for non-blocking (asynchronous) functions, as known from many sockets implementations.
  • {X} textOut and (./) dec2hex are slow. String-handling is slow. What can be done? Consider various performance improvements, use the Profiler.

Version Discussions

  • (./) Proposal for new toolbox commands with USB support, discussion about changes for toolbox version 2.00, see here: DiscussionRelease2.00 (16.5.2008)


  • (!) Overview and comments about comparison between other solutions for MATLAB: Toolboxes from Chikamasa, The MathWorks
Last modified 9 years ago Last modified on Dec 7, 2009, 3:57:12 PM