Legos, Java, Programming Assignments and CS1

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Legos, Java, Programming Assignments and CS1
An assignment scenario
David J. Barnes The University of Kent at
Canterbury d.j.barnes_at_ukc.ac.uk http//www.cs.ukc.
ac.uk/djb/
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Context

• I use LEGO Mindstorms computer-controlled
  models as a motivational tool.
• As additional material in my teaching.
• As part of a promotional talk to prospective
  students.
• With school children.
• Paper in SIGCSE 2002 on pedagogical issues with
  their use for teaching Java.

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Criteria for scenario selection

• The scenario should be interesting.
• Possibly grounded in the real-world.
• Rich in possibilities for discussion.
• Collateral learning is very important to me.
• It should present design alternatives.
• Software.
• Legoware.

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The Time-Team scenario

• Caveat this is possibly not an original idea.
• OO reuse ?
• A scenario for using arrays.
• The task is to map an area in some way.
• Geophysical mapping by archaeologists.
• Ground-surface mapping for navigation.
• Mobile temperature mapping.

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Constraints of the scenario

• The data is to be visualised on a PC.
• The amount of data to be gathered is too much to
  fit fully in the models limited memory.
• Communication with the PC must be face-to-face.
• The IR transmitter of the RCX must be directed to
  the IR tower of the PC.

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Host PC
Tower
Area to be Mapped
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Discussion

• RCX to PC communication is not a problem
• rcxcomm package from DTU.
• Could the model read and transmit values one at a
  time?
• How can the model store a collection of values to
  be sent as a group?
• What sort of path should the model follow?

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Discussion

• How do we take regular readings?
• What characteristics does the model need to
  provide values that are meaningful?
• Others?

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Implementation

• Once the issues have been addressed, a particular
  model could be provided.
• Plus software to drive the model at an
  appropriate level of abstraction.
• This keeps the focus on array manipulation.
• The host visualisation could also be provided a
  simple JFrame with a JPanel.

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Extension ideas

• Use a temperature sensor for temperature mapping.
• Physical accuracy in the model is probably less
  of an issue.
• Readings may take longer.
• Since maps are often for the purpose of
  navigation, have the host instruct the model to
  go somewhere based on the map data.

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Summary

• Mindstorms models provide a valuable tool for
  creating credible real-world scenarios.
• Appropriate scenarios can provide a rich source
  for discussion as well as a vehicle for use of
  particular language features.