Lesson 28

Card 3.6: Joystick Mapping

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Format: Code + feel test

Time: 40 min

Prerequisites: Card 3.1; a Python ladder rung or partner helps

Core Question

A joystick reports numbers; a thruster wants pulses. The function between them decides whether the robot feels surgical or drunk. What should that function be?

Resource (~10 min)

Read raw axis values from our controller live on screen. Notice it never quite rests at zero: sensor noise and spring slop. This is why deadzones exist.
Three mapping ideas on the whiteboard: straight linear, deadzone plus linear, and an expo curve that softens the center and keeps full authority at the edges.

Activity

Using the provided starter script, implement a deadzone and one nonlinear mapping. Test each mapping on the bench-spin station or LED rig and have a partner do a blind “feel test”: which mapping makes it easiest to hold 10% output steadily? Record which mapping won and why.

Clearing This Card

Your mapping code plus the feel-test result, and a 90-second oral check: “The pilot says fine positioning during the coral task is impossible. Which part of the mapping do you change, and what is the tradeoff at full speed?”

If You Miss This Class

Starter script and controller in the bin; recruit any student for the blind feel test during studio time.

Why This Matters

Mission points come from precise manipulation, and precision lives in this function. This card also produces a DDR candidate: the pilot’s mapping is a real design decision the team should be able to defend.