--- title: "From simulator to breadboard" subtitle: "Arduino · Real hardware · Lesson 6" --- # From simulator to breadboard **Name:** {{field-24}} **Date:** {{field-15}} **Class:** {{field-15}} > **Key question:** Real parts don't snap together like Tinkercad's. A breadboard holds them with hidden metal strips underneath. Put a leg in the wrong hole and the circuit quietly doesn't work. Which holes are joined? :::teacher-note **In one sentence:** Students click breadboard holes to see the hidden strips, fix an LED whose legs share a strip, trace a loop strip by strip, straddle the gap and use the rails, build the circuit on a real breadboard and upload the blink, then place every part themselves. **Students should be able to say:** I can say which breadboard holes are joined. I can place parts so each leg is in a different strip. I can build a circuit on a real breadboard and upload a sketch. **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. ::: ## Predict :::keep-together **The LED's long leg is in c8 and its short leg in d8. The rest of the circuit is fine. The LED…** ☐ Burns out ☐ Lights dimly ☐ Lights: both legs are in holes ☐ Stays dark: both legs are in the same strip, so the current goes round it My prediction, and why: {{lines-3}} ::: :::teacher-note **What happens:** It stays dark. c8 and d8 are in the same strip (column 8), so the strip joins its two legs and the current takes the easy path round the LED. ::: ## Run Try it on the board in the tutorial. Was your prediction right? What was different? {{lines-2}} ## Worked example: trace the strips :::keep-together ### Strip by strip 1. $\text{pin 13} \to \text{a3}$ — The wire puts pin 13 into column 3's strip (a3–e3). 2. $\text{resistor: b3} \to \text{b7}$ — One leg in column 3, one in column 7: it joins the two strips. 3. $\text{LED: c7 (+)} \to \text{c8 (−)}$ — Long leg in column 7, short leg in column 8. 4. $\text{d8} \to \text{GND}$ — The GND wire takes column 8 back to the Uno. 5. $\text{one loop, four strips}$ — Every part bridges two strips; no part has both legs in one. Now: which holes are joined to a3? **Which holes are joined to a3?** ☐ a1 to a17 ☐ None: each hole is separate ☐ Every hole in column 3, a to j ☐ b3, c3, d3 and e3 ::: :::teacher-note **Answer:** b3, c3, d3 and e3 Column 3's top strip: a3 to e3. ::: :::keep-together ### Find the mistake **Sam thinks this LED (long leg c7, short leg c8) is shorted out. It isn't. Click the line where Sam's reasoning first goes wrong.** ``` 1 The LED's long leg is in c7 and its short leg in c8. 2 Row c joins c7 and c8. 3 So the current goes from c7 to c8 through the row. 4 So the LED is shorted out, and Sam moves it. ``` Line: {{field-15}} Why is it wrong? {{lines-2}} ::: :::teacher-note **Answer:** line 2 Line 2: rows aren't joined. c7 is in column 7's strip and c8 in column 8's, so the LED's legs are in different strips: the loop goes through it. ::: :::typical ## Vary: the gap and the rails **Across the gap.** **On the rails.** Work in the tutorial. Plan first: what will you change, and how will you test it? {{box-4}} ::: :::typical ## Build it for real Before you plug in the USB cable: check that 5V and GND are never in the same strip. Work in the tutorial. Plan first: what will you change, and how will you test it? {{box-4}} ::: ## Which holes? :::keep-together ### Which holes? **A resistor has one leg in a12 and the other in a16. Which holes are joined to the second leg?** ☐ a12 to a16 ☐ Every hole in row a ☐ b16, c16, d16 and e16 ☐ f16 to j16 ::: :::teacher-note **Answer:** b16, c16, d16 and e16 Column 16's top strip. ::: :::keep-together ### A short **A wire goes from 5V straight into the same strip as a wire from GND. What happens?** ☐ A short circuit: a huge current; unplug it at once ☐ Nothing: no parts are in the way ☐ The LED gets brighter ☐ The board turns off safely, no harm done ::: :::teacher-note **Answer:** A short circuit: a huge current; unplug it at once 5V joined straight to GND has no resistance to limit the current. ::: ## Make: build it from scratch Work in the tutorial. Plan first: what will you change, and how will you test it? {{box-4}} ## Exit ticket :::keep-together **An LED's legs are in b14 and e14. Will it light? Why?** {{lines-3}} ::: :::teacher-note **Answer:** No: both legs are in column 14's strip, so the current goes round it. :::