---
title: "Parking assistant"
subtitle: "Capstone projects · Years 8–9: sense and respond · Lesson 2"
---

# Parking assistant

**Name:** {{field-24}} **Date:** {{field-15}} **Class:** {{field-15}}

> **Key question:** Reversing cars beep faster as they get closer to a wall. Can you build one, and prove it warns at the right distances?


:::teacher-note

**In one sentence:** A Years 8–9 design project: a parking assistant with an ultrasonic sensor and three warning bands, planned with band-edge tests, prototyped on the board, built in Tinkercad and optionally on hardware, tested with a ruler and evaluated.

**Students should be able to say:** I can plan tests for every edge of a set of bands. I can read a distance sensor and act on it. I can evaluate my design against each criterion with evidence.

**Width:** the unmarked parts are the floor every student does (predict, run, investigate and make). Typical adds the modify practice; wider adds the real-world contexts. They add contexts, not difficulty. Students work in the online tutorial alongside this sheet.

:::


## Inquire: the brief


:::keep-together

**Sort each line of the brief: a criterion (what it must do, which you can test) or a constraint (a limit you must work within)?**

Groups: Criterion, Constraint

- Off over 100 cm: {{field-15}}
- Blinks or beeps from 30 to 100 cm: {{field-15}}
- Steady under 30 cm: {{field-15}}
- HC-SR04 sensor and a buzzer or LED from the kit: {{field-15}}
- USB power: {{field-15}}

:::


:::teacher-note

**Answer:** Off over 100 cm → Criterion; Blinks or beeps from 30 to 100 cm → Criterion; Steady under 30 cm → Criterion; HC-SR04 sensor and a buzzer or LED from the kit → Constraint; USB power → Constraint

Criteria are what you will test at the end; constraints decide what you are allowed to build with.

:::


## Develop: plan before you build


:::keep-together

### Band edges

**How many test readings do you need at minimum to check every band edge (30 and 100), on both sides?**

☐ 2: 30 and 100

☐ 1: 50

☐ 4: 29, 30, 100, 101

☐ 3: one in each band

:::


:::teacher-note

**Answer:** 4: 29, 30, 100, 101

Each edge needs the reading just inside and just outside it.

:::


## Create: build it


**In the simulator.** 

**For real.** 

Work in the tutorial. Plan first: what will you change, and how will you test it?

{{box-4}}


:::wider

## Test: run your table


**Run the tests.** 

**Fix and re-test.** 

Work in the tutorial. Plan first: what will you change, and how will you test it?

{{box-4}}

:::


## Evaluate: against the brief


:::keep-together

### Which is evidence?

**Which is the strongest evidence that the design meets a criterion?**

☐ A test from the table that set the input and recorded the expected result

☐ The code has no errors

☐ It worked when I tried it

☐ My partner said it looks good

:::


:::teacher-note

**Answer:** A test from the table that set the input and recorded the expected result

A planned test with a recorded result is evidence; everything else is a feeling.

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## Exit ticket

:::keep-together

**Give the four test distances that check your band edges.**

{{lines-3}}

:::


:::teacher-note

**Answer:** 29, 30, 100 and 101 cm.

:::