---
title: "Off the breadboard"
subtitle: "Capstone projects · Stretch: make it permanent · Lesson 7"
---

# Off the breadboard

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

> **Key question:** A breadboard circuit falls apart in a school bag. How do you make it permanent?


:::teacher-note

**In one sentence:** A stretch project: move a working breadboard project onto protoboard or stripboard, with a planned layout, a soldering safety briefing, and the original test table re-run.

**Students should be able to say:** I can plan a protoboard layout from a circuit diagram. I can solder safely and check my joints. I can show the permanent version works the same as the breadboard one.

**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

- Passes the same tests as the breadboard version: {{field-15}}
- No loose wires: {{field-15}}
- Fits on a 5 × 7 cm board: {{field-15}}
- Soldering only after the safety briefing, in the soldering area: {{field-15}}

:::


:::teacher-note

**Answer:** Passes the same tests as the breadboard version → Criterion; No loose wires → Criterion; Fits on a 5 × 7 cm board → Constraint; Soldering only after the safety briefing, in the soldering area → 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

### Track cuts

**On stripboard the copper strips join every hole in a row. An LED's two legs must go in the same row, but must not be joined. What do you do?**

☐ Put the LED the other way round

☐ Cut the strip between the legs

☐ Solder them together

☐ Use a bigger resistor

:::


:::teacher-note

**Answer:** Cut the strip between the legs

A track cut breaks the strip so the legs are in separate pieces, as on a breadboard.

:::


:::keep-together

### Soldering safety

**Soldering: safe or unsafe?**

Groups: Safe, Unsafe

- Iron back in its stand whenever you put it down: {{field-15}}
- Fume extractor on, face out of the smoke: {{field-15}}
- Testing whether the iron is hot with a finger: {{field-15}}
- Cutting component legs with the board pointing at a classmate: {{field-15}}
- Washing hands after soldering: {{field-15}}

:::


:::teacher-note

**Answer:** Iron back in its stand whenever you put it down → Safe; Fume extractor on, face out of the smoke → Safe; Testing whether the iron is hot with a finger → Unsafe; Cutting component legs with the board pointing at a classmate → Unsafe; Washing hands after soldering → Safe

The iron is around 350 °C; the fumes and offcuts are hazards too.

:::


## 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?**

☐ It worked when I tried it

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

☐ The code has no errors

☐ 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.

:::


## Exit ticket

:::keep-together

**Why plan a protoboard layout before soldering?**

{{lines-3}}

:::


:::teacher-note

**Answer:** Parts can't be moved easily once soldered, so the layout must match the circuit first.

:::