Learning Goals 3 min
By the end of this lesson you will be able to:
- Build the Lifting Flying Chair with its Medium Motor in port A.
- Change the Brick's status light with set status light to [green v] — green for ready, red for stop.
- Write the current speed on the screen as the chairs swing out.
Meet the Model — the Flying Chair 6 min
What is a flying chair?
A flying chair is a fairground ride with seats hung on chains from a tall spinning roof. As it turns, the chairs swing out and rise into the air. It is often called a chair-o-plane or swing carousel.
The science behind it
As the ride spins, the hanging chairs swing outward and rise — that is circular motion. The faster it turns, the higher and wider the chairs fly. A force pulls them inward toward the centre, called centripetal force; without it the chairs would fly off in a straight line.
Where you meet it
You meet flying chairs at funfairs and theme parks. In Malaysia they show up at the travelling pasar malam and carnival grounds.
What we'll build
We'll build a swing carousel driven by a Medium Motor on port A. The Brick's status light shows green for go and red for stop, so a watcher reads the ride at a glance.
Warm-Up 4 min
The Brick has a light ring around its buttons. You can colour it green, orange or red.
Quick-fire puzzle
Jun Kai runs this. What colour is the Brick light while the chairs spin?
when program starts :: events hat set status light to [green v] :: display [A v] set speed to (60) % :: motors [A v] run [clockwise v] for (6) [rotations v] :: motors set status light to [red v] :: display
Reveal the answer
The light is green while the chairs spin for six rotations. When the motor stops, the light turns red. Green means "running"; red means "stopped" — just like traffic lights.
New Concept — status light and live readouts 10 min
The status light is the ring around the Brick buttons. It is a quick way to show "ready", "busy" or "stop" without words.
Blocks reference
| Block | Category | What it does |
|---|---|---|
set status light to [green v] :: display | Display | Lights the Brick's button ring. Choose green, orange or red. |
write [Speed] at line (1) :: display | Display | Writes a label or a value on the screen. |
[A v] set speed to (60) % :: motors | Motors | Sets the chair-spinning speed. |
Colours that mean something
Pick colours that match the action: green for go/ready, orange for warming up, red for stop. A watcher understands the robot at a glance.
Why it matters
A fairground ride shows a green light when it is safe to board and a red light when it is moving. Status lights are everywhere — chargers, routers, game consoles. They are feedback without sound or words.
Build & Program — the Lifting Flying Chair 17 min
Part A — Build
Build the Lifting Flying Chair. A Medium Motor spins a top hub; the chairs hang on strings and swing out as the speed rises.
Components & ports: EV3 Brick · Medium Motor → port A.
- Build the central tower and mount a spinning hub at the top.
- Hang the chairs from the hub on short strings so they swing freely.
- Drive the hub with the Medium Motor through a gear; plug it into port A.
- Spin by hand to check the chairs lift outward as the hub turns faster.
Part B — Program
Show a green "ready" light and the speed, run the ride, then turn the light red.
- Start the program and clear the screen:
when program starts :: events hat
clear display :: display
- Show the green "ready" light:
set status light to [green v] :: display
- Write the speed readout:
write [SPEED 60] at line (1) :: display
- Set the speed and spin the chairs:
[A v] set speed to (60) % :: motors
[A v] run [clockwise v] for (8) [rotations v] :: motors
- Turn the light red when it stops:
set status light to [red v] :: display
when program starts :: events hat clear display :: display set status light to [green v] :: display write [SPEED 60] at line (1) :: display [A v] set speed to (60) % :: motors [A v] run [clockwise v] for (8) [rotations v] :: motors set status light to [red v] :: display
Expected behaviour: the light turns green, the screen shows SPEED 60, the chairs swing out for eight rotations, then the motor stops and the light turns red.
What changed: the robot now shows its status two ways at once — a coloured light and a screen readout.
Try It Yourself — three small builds 11 min
Goal: Use an orange "warming up" light before the green "running" light.
when program starts :: events hat set status light to [orange v] :: display wait (2) seconds set status light to [green v] :: display [A v] run [clockwise v] for (8) [rotations v] :: motors
Goal: A faster ride with a matching readout. Show SPEED 90 and spin at 90%.
when program starts :: events hat clear display :: display write [SPEED 90] at line (1) :: display set status light to [green v] :: display [A v] set speed to (90) % :: motors [A v] run [clockwise v] for (8) [rotations v] :: motors
Goal: Devi wants a full ride cycle: orange "boarding", green "running" ride, then red "stopped" with a goodbye beep.
when program starts :: events hat set status light to [orange v] :: display wait (2) seconds set status light to [green v] :: display [A v] run [clockwise v] for (8) [rotations v] :: motors set status light to [red v] :: display play beep (60) for (0.2) seconds :: sound
Mini-Challenge — the safe ride panel 6 min
Combine today's status light with the screen text from last lesson. Build a ride that shows a green light and a "RUNNING" message while moving, and a red light and "STOPPED" message when done.
It works if:
- Light and screen agree: green + RUNNING while moving, red + STOPPED when finished.
- You clear display before writing the second message.
Recap 2 min
You used the Brick's status light as feedback. set status light to [green v] lights the button ring — green for go, orange for warming up, red for stop. Paired with a screen readout, your robot now reports its status clearly.
- set status light (block)
- Lights the ring around the Brick buttons in green, orange or red.
- Status light
- The light ring that shows the robot's state at a glance, without words.
- Readout
- A value (like speed) written on the screen so you can see it live.
Homework 1 min
Traffic-light ride. Make your ride show orange, then green, then red at the right moments.
Bring back next class: a screenshot of your program and a note of which colour means what.
Heads up for next class: EV3-L1-07 builds the Wipers and plays a sound on every back-and-forth sweep.