Instruction Guide: The Robo-Tagger
This lesson ties together all the learning to date. The students must design a robo-tagger that will use a dry-erase marker to write block characters on a horizontal white board. Block letters are used to force the students to use a third motor to raise/lower the marker between characters. Constraints on the size, spacing and alignment of letters forces precision maneuvering.
This "Problem Solving with Programming" pdf from the "Challenges" page in "NXT Video Trainer 2.0" discusses the incremental design. This approach of breaking a large task down, and then incrementally designing/testing one piece at a time is a great antidote to most students' compulsion to jump right in at try to write a complex program all in one step.
Robo-Tagger Challenge
This challenge is laid out in the Robo-Tagger Task Assignment Sheet:
- The included challenge has student write "10". To extend the challenge, select other letters or digits that have meaning to the students but also include both straight and curved segments. Having students write their school initials (which likely end in ..HS or ..MS) ups the ante significantly since the "H" or "M" requires aligning sequential straight segments and the S requires aligning half-size (compared to "0") semi-circles.
- If desired, use electrical tape to add a black border or other registration marks on the whiteboard to assist with alignment (using the light sensor)
- You can decide whether or not to allow use of the sound sensor to control robot actions (or don't mention it and see if anyone thinks of it).
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Have students explain the following:
- How they made trade offs in their hardware design (how/where they attached/moved the marker,etc.) and the implications of these choices on their software design
- How their flow chart/pseudocode describes the overall program design
- How their NXT-G program implements each of the blocks in their flow chart (including comments that identify the flow chart blocks/pseudocode )
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Ask about the program development process - did they use the incremental approach?
- What other "Best Practices" would they recommend for program development
Have students document the steps of the Engineering Process (restate challenge in their own words, identify related web sites, etc.) that they use in developing their dragster. This Engineering Process Log Word file may be used to document these steps.
These resources may be used for pseudocoding or these for Flowcharting.
