# 🦾 Lesson Plan — Servo Lab

> **Ages 8-13 · 45 min · 1 robot per pair (servo arm attached)**

## 🎯 Objective
Students command a servomotor to a precise angle, understand the **PWM = analog control** principle, and record a 5-step choreography.

## 🧰 Materials
- 1 Maqueen Lite v4 robot per pair (charged), with at least one servo (S1) attached
- 1 laptop/tablet per pair (Chrome or Edge)
- Protractor (printed or plastic)
- Sticky notes for marking arm positions

## 📋 Lesson flow (45 min)

| Time | Phase | Teacher | Students |
|---|---|---|---|
| 0-5 | **Hook** | Show a wave with your hand. "Could the robot do this exactly?" | Predict whether a robot arm is more or less precise than a hand. |
| 5-10 | **Demo** | Open Servo Lab. Drag S1 slider 0° → 90° → 180°. Use the protractor to measure the actual angle. | Watch; estimate the difference between commanded and measured angle. |
| 10-25 | **Exploration** | Pairs connect, drive S1 to 5 chosen angles, mark each with a sticky note. Compare with neighbours. | Calibrate the servo; note any drift between robots. |
| 25-40 | **Challenge** | "Record a 5-step choreography that ends at the start position. Replay it three times in a row." | Use the **record/replay** mode; refine timing. |
| 40-45 | **Reflection** | "Why does the same angle command produce a slightly different position on each robot?" | Discuss tolerance, calibration, mechanical play. |

## ✅ Success criteria
- I can move the arm to a target angle within ±5°.
- I can record a 5-step sequence and replay it.
- I can describe what happens to the arm if I push slider to 90°.

## 📚 Standards
- **FR Cycle 3** — *Sciences-Tech* : transmission/transformation de mouvement.
- **FR Cycle 4** — *Tech* : actionneurs (servomoteurs), commande, signal PWM.
- **NGSS** — 4-PS3-2 (transfer of energy); MS-ETS1-2 (evaluate competing solutions).
- **CCSS-M** — 4.MD.C.5 (angles); 5.G.B.4 (classify shapes).
- **CSTA** — 1B-AP-12 (modify existing program); 2-AP-13 (decompose problems).

## 🚀 Extension
- Mount a small flag on the arm and play "wave at the audience".
- Combine with a second servo (S2) to make a 2-axis pointer.
- Bridge to **Robot Soccer** (Push kit) — use the servo as a flap.