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Lesson 4 · Module 3 Final Project

Module 3 · Grid Driving

Lesson 4 · Module 3 Final Project

50–60 minCapstoneDrive a square
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Time to tie the module together. Your robot will drive a complete square on the grid — two intersections per side, turn right at each corner, four times — and end up right back where it started. Same LineTrack class, no new Python: just your tools, put to work.

Learning Objectives

By the end of this project you will be able to:

  • Design a program that drives a closed square path on the grid
  • Use a for loop to repeat a drive-and-turn sequence
  • Test and tune a real robot until the path closes
  • Verify the robot returns to its starting position
Printable knowledge checks — the 2 questions from this lesson on one page, with room to write. Teachers: answer key.

The mission​

Make the robot drive a square: each side is 2 intersections, with a right turn at each of the 4 corners. Done right, it finishes where it began.

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Diagram — grid with a square path, 2 segments per side, right turn at each corner, start = end
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Four sides, four right turns, back to start. One loop iteration draws one side.

Your program must: use the LineTrack class, drive the square with a for loop (not four copied blocks), print progress, and return to start.

One loop, four sides​

The whole square is a four-iteration loop: each pass drives one side, then turns the corner. Two pieces to write — a drive_intersections(tracker, count) helper (you built this in Lesson 2) and the loop that calls it and turns.

Sketch the loop body in English first: what happens once per side?

Notice there's no separate clear before turn_right() — the turn clears the corner itself (Lesson 3). Four right turns add up to a full 360°, which is why the robot comes back around.

Knowledge Check

The square loop runs turn_right() once per side, four times. How many total degrees does the robot turn?

Activity · Test one side at a time​

Don't run all four sides first. Build up:

  1. One side — comment out the loop; run one drive_intersections(2) + turn_right().
  2. Two sides — range(2). What shape should that give you? Predict, then run.
  3. Full square — range(4); does it close back to the start?
Knowledge Check

A student wrote `for leg in range(3):` and added a clear step right before turn_right(). What are the two bugs?

Activity · Extend it​

Once the square works, try a variation:

Bigger

3-per-side square

Set sides = 3 for a larger square. Does it still close?

Rectangle

Alternating legs

Use a list [2, 3, 2, 3] and index it by leg so opposite sides differ.

Mirror

Left-turn square

Swap in turn_left() to drive the square the other way around.

Activity · Reflect​

Demo your square and think back:

  • What was hardest to get working, and how did you fix it?
  • Why is the for loop better than copying the side code four times?
  • How is this different from the polygon function in Module 1? (There you set distances and angles; here you count intersections and follow real lines.)

Nice work — Module 3 done 🎉​

You reused a class you wrote weeks ago on a brand-new surface, learned to clear intersections and count segments, and sequenced drives and turns into real paths. Every route here was one you planned and hard-coded. That's about to change.

Resources​