Home | Preview | News | In the Press | Projects | Features | Download | Development | Bug Reports | FAQ | Login

---

Newsflash

• New I²C sensors (compass, acceleration, IR, color) are to be tested and implemented.

• New Ultrasonic Sensor mode "snapshot" (aka PING-Mode or SINGLE_SHOT) successfully implemented and tested.
  Observed multiple echos seems complex, might not be as useful as expected.

• Lowlevel private functions dec2wordbytes and wordbytes2dec rewritten and optimized by about factor 10.

• Using the LeJoS software instead of the LEGO original firmware should be working more robust for motor control (tests are required)

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

• NXT-USB communication successfully tested (using official LEGO Mindstorms NXT Fantom Driver Version 1.02 on Windows and libusb on Linux).
  Toolbox-Prototype with USB support is being developed, first tests point towards data rates of about 150 analog sensor / motor requests per second (as opposed to a maximum of about 15 per second using Bluetooth). See here for details: USBStuff (29.4.2008)

Brainstorming & Further Concepts

Firmware

• 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!

Communication

• 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?

USB

• 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

Bluetooth

• 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 !"""
  		brick.write_io_map(131073,motor.port*32+22,P)
      brick.write_io_map(131073,motor.port*32+23,I)
      brick.write_io_map(131073,motor.port*32+24,D)
      update(motor,Update.PID_VALUES)
  

• 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

• 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.

• Add verbosity-level support in textOut.m and of course in all files using it, to enable complete and detailed logging, that is configurable.

• textOut and dec2hex are slow. String-handling is slow. What can be done? Consider various performance improvements, use the Profiler.

• Apparently the commands pause and tic / toc have only an accuracy/resolution of 15ms when using Windows or Linux (someone said)? Is that true? Investigate how accurate they are and decided wether it still makes sense to use SendSendPause and SendReceivePause…

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)

Miscellaneous

• Overview and comments about comparison between other solutions for MATLAB: Toolboxes from Chikamasa, The MathWorks

• This page provides a developer's notepad to discuss further concepts → Further Concepts (German)

Checklist for New Releases

This todo-list might have to be updated for future public releases with many developers / contributors collaborating, it was first intended for internal use and then published → Checklist for New Releases.