Project 6 XGO Draws A Square

Ⅰ. Teaching Aims

Consolidate the segmentation thinking of “walk - stop - turn - stop” and avoid taking arcs.
Use repeat to simplify the repeated path.
Adjust the step size and waiting time through distance measurement, making the displacement more accurate.
Use the forever infinite loop to perform square movements.

XGO + Foxbit + MicroBlocks IDE.
Prepare an 80 cm × 80 cm blank floor and stick positioning points at the four corners with tape.
XGO battery power ≥ 60 %.
MicroBlocks status bar shows a green dot, XGO-lite extension is loaded and the development board model is Foxbit.
If precise distance measurement is required, prepare a tape measure or stick a scale paper tape on the ground.


Functions	`n ∈ [−100, 100]`; positive for forward, negative for backward
Common misuses	The walking section still gives `turn` → Take an arc

Functions	Maintain the previous instruction for ms milliseconds
Common misuses	Write milliseconds as seconds → Wait too short

Functions	`n ∈ [−100, 100]`; positive for left, negative for right; additional `wait` is required
Common misuses	Forgot `turn 0` to zero out

Functions	Loop the code block k times
Common misuses	Forgot to write `wait` in the loop

Functions	Forever loop

Hard ground, 6.0V experience value:

Calculation:

Waiting time(ms) ≈ Target distance(cm) ÷ (distance each 1000 ms) × 1000

Example: target distance is 30 cm, so we use a step size of 60 → 30 ÷ 15 × 1000 ≈ 2000 ms

Click ▶Run, and then measure the displacement with a ruler; If the deviation is greater than 3 cm, fine-tune and wait for ±100 ms.

Online code: Click here

Requirement: Walk 30 cm → turn right at 90° → repeat 4 times, and finally return to the starting point.
Recommended:
- Go straight: walk 60 + wait 3000
- Stop: walk 0 + wait 500
- Turn: turn 90 + wait 1800 （≈ 90°）
- Zero out: turn 0 + wait 200

Loop script sample:

Online code: Click here

Debugging tips:

The turning angle is • too small → wait +50~100 ms • too large → wait −50 ms
The route is trapezoidal → Reduce the step size to 50, and ensure the ground is flat.

Why is it necessary to walk 0 before starting the turn after the straight section ends?
If we modify it to turn left and draw a counter-clockwise square, which two parts of the script should be changed?
How to package “step size, distance, angle” with custom blocks to improve reusability?

Questions	Possible causes	Solutions
Walk in an arc line	Still set `turn` in the walking section	Section: Reset to zero after walking and then turn
The turning angle is too small / too large	`wait` is mismatching	Fine-tune in steps of 50 ms
It’s still rotating after turning	Forgot `turn 0`	Reset to zero immediately after the turn
Cannot return to the starting point	The accumulation of errors in walking distance	Slow the speed down, increase friction, or recalibrate