Lego Robot

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Lego Robot

• Jan Jantzen
• Technical University of Denmark

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Summary

• Build standard robot
• Program and test it
• Build better robot
• Program and test it
• Write report

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Constraints

• 15 BSc students, 1st year
• 7 consecutive work days
• Assessment report, pass/no pass
• Low cost (
• Repeat twice

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Standard robot
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RCX 1.0 Hardware

• 3 digital output ports 0-9 volts
• PWM in 1, 2,..., 8 msecs
• 3 analog input ports 0-5 volts
• A/D in 0, 1, ..., 1023 raw value
• Reads port every 3 msecs
• IR link has 2 IR LEDs, requires line of sight
• Two RCXs can communicate via IR link
• Loudspeaker

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RCX Software

• Max 5 programs, 1 at a time
• Max 10 // tasks per pgm
• Hitachi H8, 16 MHz
• 16 kB ROM 512 B RAM
• 32 kB SRAM
• Firmware 16 kB, user pgm 6 kB, stack and log 10
  kB
• Timers at 0.1 secs resolution 0 32767
• Software clock

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RCX programming
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BricxCC and NQC
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Examples of components
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IR tower

• Alkaline or rechargable battery 9V
• Lasts 30 hours avg
• Short max 0.5 m
• Long max 2.5

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Evaluation

• Lego for RoboCup, even belt drive, is feasible
• Motors behave unequal turns, straight run
• To few sensor inputs
• Annoying to spend 50 time on test runs (in the
  basement)
• Need more programming experience
• Free format good vs want more specs
• Learning outcomes programming, calibration,
  design, control

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Another evaluation

• Not patient
• Not enduring
• Not academic

• Independence
• Self-discipline
• Creativity

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References

• W.J. Taffe Programming Lego Robots Using NQC.
  Plymouth State University, USA Dept. of Computer
  Science and Technology, Nov 2002 (adapted from
  Mark Overmars, 1999) URL http//turing.cs.plymouth
  .edu/wjt/HonorsIntro/Robotics/markovManual.pdf
• D. Baum J. Hansen NQC Programmers Guide (v
  3.0 a1). (Included in BricxCC)
• NQC -- Not Quite C, http//bricxcc.sourceforge.net
  /nqc/
• BricxCC, http//bricxcc.sourceforge.net/