Mindstorms

MindStorms is a ``Robotics Invention System''

• A 16-bit computer called the RCX (a 16MHz Hitachi H8/3297), with 32k RAM
• The RCX can control 3 motors and read from 3 sensors
• Additional Lego parts - gears, wheels, sensors, motors
• Software can be downloaded by an infra-red link on a serial port
• Programs can be downloaded and run, or "immediate" commands can be run
• Normally programmed from a visual programming environment or from VB
• On a PC, interface to RCX is managed by an OCX
• Low-level machine-code is sent across the IR link

Lego and Java

• The Mindstorms robot only has 32k of RAM
• The CLDC configuration (using the KVM) requires 160k
• Therefore, Mindstorms cannot run as a J2ME device
• There is a really tiny version of Java that will run in the Mindstorms

Tiny devices and proxies

Run a proxy on a Java-capable device that "represents" the device

Mindstorms control

• The Mindstorms robot has a microcontroller that defines an instruction set as bytecodes, including

  Mindstorms programs

  • Programs can be downloaded to the Mindstorms using the IR link
  • Single instructions can also be downloaded and run immediately, again by the IR link

  Mindstorms proxy

  A proxy for the Mindstorms robot is built using the following components

  • Native code serial port DLL
  • Java CommAPI
  • Proxy on top of this
  

  RCXPort

  Dario Laverde has defined a proxy class

  Example use of RCXPort

  ---

  Jan Newmarch (http://jan.newmarch.name)
  jan@newmarch.name
  Last modified: Mon Mar 31 04:29:33 EST 2003
  Copyright ©Jan Newmarch

  Instruction	Bytecode
  PING	0x10
  SETMOTORPOWER	0x13
  CALLSUB	0x17
  PLAYSOUND	0x51
  SETMOTOR	0x21