Sensors & Switches

A switch makes the wearer part of the circuit. A sensor makes the world part of it. This is the deepest end of the course: pieces that respond.

Start dumb (it’s smarter)

Before any code, build a mechanical switch — two copper tape pads that touch when something moves:

• A clasp switch: bracelet closes, circuit closes, lights on.
• A paperclip switch: remember Sheriff Boxy from Trashion Fashion? A paperclip completing the circuit is a switch, and it shipped.
• A pressure switch: two pads with foam between them — lights that fire on a handshake, a step, a hug.

Mechanical switches are free, unbreakable by software, and teach the core idea: input changes output.

Then let the board listen

Your micro:bit or Circuit Playground ships with senses: buttons, tilt/shake detection, light level, sound, temperature. Each one is a story trigger:

• Shake → the piece flares (anger, alarm, applause?)
• Darkness → the piece wakes up (what does your cause do when nobody’s watching?)
• Sound level → lights climb with crowd noise (a piece the audience powers!)
• Touch → one LED of hope lights per handshake

Pick the sensor after you pick the sentence: “When ___ happens, my piece ___ — because the story says so.”

What this looks like at full power

Razor Wings — one of our favorite pieces ever walked: ask a rough-and-tumble student what she wants to build and you get wings with attitude, built to move. Read the build story. And for where sensing can ultimately go, our NFC-powered lights experiment made garments respond to a tap of a phone.

Kiki’s Dual Emotions from last lesson is the complete thought: sensor → emotion → light. That’s the ceiling this course points at — and students reach it.

The final challenge

Add one responsive element to your team’s piece — mechanical or sensed — that a runway audience will actually notice at the pause. Then rehearse it: responsive pieces change the model’s choreography (now the walk triggers the story).

For teachers: Enforce the one-element rule ruthlessly; responsiveness is where scope creep eats teams alive the week before a show. The mechanical switch track means this lesson fully works with zero microcontrollers — sensors are the extension, not the requirement.

Before the runway takes you

• Your piece responds to something, on purpose, reliably — ten times out of ten
• The response is in the artist statement, because it’s part of the argument now