class: center, middle, inverse, title-slide .title[ # Your Game — the Circuit, and the Plan ] .subtitle[ ## Programmable Electronics — Unit 2 ] .date[ ### Class 14 ] --- # Learning Targets .lt-box[ - Rebuild a working circuit from your own documentation, and find out how good that documentation actually was. - Turn a bench prototype into something that survives being handled — tidy layout, secured leads, nothing that can pull loose. - Design a physical game around a fixed circuit, and justify the design to somebody who hasn't seen it. - Explain what your game does in ten seconds, out loud, to a stranger. ] .eu-label[Essential Understanding:] A circuit that works on your bench and a circuit that works in someone else's hands are two different objects. The gap between them is not more cleverness — it's tidiness, strain relief, and having thought about what a stranger will do to it. That gap is where most real engineering time goes, and today is the first time in this course you have to cross it. --- # Agenda .agenda-box[ 1. Prototype vs. product 2. **Build (25 min):** the circuit, for real this time 3. The bench test that isn't optional 4. 90-second pitches 5. **Design (20 min):** plan the thing you'll build next class 6. Claim your materials ] --- # Prototype vs. product Last class you got the Operation circuit **working**. That's not the same as **finished**. .pull-left.w48[ **What you built was a prototype.** Its job was to answer one question: *does this idea work?* It answered yes, and then you went home. A prototype is allowed to be ugly. It's allowed to have a wire you're holding down with a finger. ] .pull-right.w48[ **What you need now is a product.** Its job is different: *does this keep working when I'm not the one holding it?* Tonight there'll be a seven-year-old yanking on your game. They are the specification now. ] .emphasis-center[ Same schematic. Completely different build. ] --- class: small-font # Build (25 min): the circuit, for real **Start from a bare breadboard** and your own notes from last class. That's deliberate — if your documentation isn't good enough to rebuild from, far better to find out now than the week of open house. 1. **Rebuild the Operation circuit.** 556, both timers, the "caught" LED, the speaker with its **100 Ω**. Same schematic as last class — pull it up if you need it. 2. **Lay it out for a stranger, not for you.** Components flat to the board, short jumpers, nothing arching over the chip. If you have to move a wire to see a pin, move the wire. 3. **The two course leads are the weak point.** They're the only part anyone will touch. Give them **at least 30 cm**, and anchor them — a knot through a hole, or a blob of hot glue where they leave the board. Pull on them, hard, on purpose. If anything moves, fix it now. 4. **Power.** Decide how yours turns off: unplug the battery clip, or leave one lead loose. You'll be running for two hours. 5. **Test it twenty times.** Not once. Touch the leads over and over and make sure you get the same 2.4 seconds and the same buzz every time. Intermittent faults do not fix themselves. 6. **Photograph it** — top-down, in focus, wires visible. That photo is your rebuild insurance. .font-small[ **Your notes were wrong somewhere.** Everyone's are. Write down what you had to work out again, and fix the page — that's the actual assignment here. ] --- # The bench test that isn't optional Before you touch a single piece of cardboard, your circuit has to pass this. Ask me to watch: .pull-left.w48[ 1. **Twenty clean triggers in a row.** Same pulse, same buzz, no misfires. 2. **The tug test.** Pull each course lead firmly. Nothing moves, nothing disconnects. 3. **The drop test** — from 10 cm onto the desk. It still works. ] .pull-right.w48[ 4. **The silence test.** Leads apart, powered on, for a full minute: no buzz, no flicker, nothing. 5. **You can point at the 556 and say what each half does.** ] .emphasis[ No cardboard until it passes. A game built around a flaky circuit is a flaky game wearing a costume. ] --- # 90-second pitches Sketches out. Each group, standing up, ninety seconds: .pull-left.w48[ 1. **What's the story?** One sentence. "You're a surgeon." "You're stealing a diamond." 2. **What's the course?** Buzz-wire, or an Operation board with foil-lined holes? 3. **How does a stranger know what to do** without you telling them? ] .pull-right.w48[ 4. **What do you need from the materials table?** .font-small[ We're listening for rule 3 — the ten-second rule. If your pitch takes ninety seconds to explain the *game*, a visitor won't get it in ten. That's fixable now and expensive to fix later. ] ] .font-small[ Everyone else: listen for the thing that will go wrong. Say it kindly and say it now. ] --- class: small-font # Two ways to build the course Both use **exactly the same circuit** — one lead to the course, one to the thing the player holds. .pull-left.w48[ ### Buzz-wire Bend stiff wire into a wiggly course. The player slides a ring or a loop of wire along it without touching. - **Best for:** journeys. A path, a river, a wire you're threading. - **Needs:** the stiffest wire in the room. Coat hanger beats solid-core beats paperclip. - **Watch out:** too tight a bend and nobody can win. ] .pull-right.w48[ ### Operation board Flat cardboard, holes cut out, **aluminium foil lining every rim**, all the foil joined to one lead. Tweezers on the other lead. Fish objects out without touching the edges. - **Best for:** collections. Organs, treasure, bones, parts. - **Needs:** foil, glue, patience with small holes. - **Watch out:** the foil has to be *continuous* — test every hole with the meter. ] --- class: small-font # Design (20 min) & claim your materials Get it on paper before you get it in cardboard. By the end of the period each group hands me: 1. **A labelled drawing** of the finished game — actual size, roughly. Where does the circuit sit? Where do the leads come out? Where does the player's hand go? 2. **Your sign.** What does it say? Games at open house get one title and at most one line of instruction. Write the exact words now — you'll print it next class. 3. **A materials list** from the table: cardboard, duct tape, craft sticks, foil, hot glue, string, paint, brass fasteners, wire. Claim what you need; there is enough, but not unlimited. 4. **One sentence on what will break first.** Every group has a weakest point. Naming it now means you'll reinforce it next class instead of discovering it at 7 p.m. .emphasis-center[ Next class is build day. You get one period. Come in knowing exactly what you're making. ]