Challenge 1
Build a show that uses movement, the screen and at least two different kinds of sound. Any order you like, but somebody watching must be able to tell where one part ends and the next begins.
What you are building 3 min
The Tyrannosaurus: two legs driven through a linkage by one Medium Motor, a heavy head, and a long tail holding the whole thing upright. It stomps forward — and it roars.
You have met every block this lesson uses. Motors, the screen, the status light, sound — all of it is Level 1, all of it is behind you.
So this lesson is not about a new block. It is about the order you put them in. The same six blocks arranged two different ways are a dinosaur stomping past, or a dinosaur roaring at you, and nothing but the sequence decides which.
In the real world 5 min
Where you have seen it
Tyrannosaurus rex was a meat-eating dinosaur of the late Cretaceous, about 66 million years ago. It walked on two powerful hind legs, carried a skull well over a metre long, and had arms shorter than yours. You meet it in films, and you meet its skeleton in museums — usually mounted mid-stride, with its tail off the ground.
Why it is built that way
Look at how that skeleton is balanced. The head is enormous and hangs out in front of the legs; the tail is just as long and hangs out behind. The legs are underneath, near the middle. The tail is not decoration — it is the counterweight that lets the animal carry its head out in front without falling on its face.
Your model has the same problem and the same solution. Build it with a short tail and it will nose-dive the first time it steps.
What would go wrong without it
The animatronic dinosaurs in museums have a second problem you are about to share. They move, light up and make noise — and if those three things happen in the wrong order the illusion collapses. A roar that arrives after the jaws have shut is not frightening. It is funny.
A performance is not a list of things that happen. It is a list of things that happen in an order.
The main concept — order is the design 6 min
Blocks run top to bottom, one after another. You have known that since your first program. Today it stops being a rule about how the Brick works and becomes the thing you are actually designing.
Here are two programs. They contain exactly the same blocks.
when program starts :: events hat write [ROAR] at line (1) :: display set status light to [red v] :: display play beep (40) for (0.2) seconds :: sound play beep (55) for (0.2) seconds :: sound play beep (70) for (0.2) seconds :: sound [A v] run [clockwise v] for (2) [rotations v] :: motors
when program starts :: events hat [A v] run [clockwise v] for (2) [rotations v] :: motors write [ROAR] at line (1) :: display set status light to [red v] :: display play beep (40) for (0.2) seconds :: sound play beep (55) for (0.2) seconds :: sound play beep (70) for (0.2) seconds :: sound
Same seven blocks. Same numbers. Completely different animal — and you did not change a single value to get there.
Building a roar out of beeps
There is no roar block. A roar is several short notes played straight after one another, each higher than the last, so the sound seems to build:
| Note number | What you hear |
|---|---|
| 40 → 55 → 70 | A growl rising into a roar. Higher number, higher pitch. |
| 70 → 55 → 40 | The same notes falling — a groan, not a roar. |
| 40 → 60 → 75 → 60 → 40 | Up and back down. A longer, more animal noise, because real roars do not stop at their loudest. |
You do not have a roar block. You have an order of beeps, and the order is the roar.
Sound on the BrickBeeps, note numbers and the sound files. Open it if the sound blocks need a refresher.Show meHide
Sound and beeps
The Brick has a small speaker. It can play one of the built-in sound files, or beep a note you choose. Sound is what makes a machine feel finished — and it is also a way for the robot to tell you something without you having to look at it.
Blocks reference
| Block | What it does |
|---|---|
play sound [Communication / Hello v] until done :: sound | Plays the sound and waits for it to finish before the next block runs. |
start sound [Communication / Hello v] :: sound | Starts the sound and moves straight on to the next block, so the sound plays while the robot keeps working. |
play beep (60) for (0.5) seconds :: sound | Plays a single note for a set time — useful for short alerts. The number is a note, not a volume: bigger means higher. |
set volume to (100) % :: sound | Sets how loud everything after it will be. Worth putting at the top of a program — the Brick remembers the last volume it was given, even from somebody else’s program. |
stop all sounds :: sound | Cuts off anything that is still playing, including a long sound started earlier. |
Wait for it, or not
These two blocks play the very same file. The difference is what the rest of the program does while it plays — so it cannot be heard on its own, only seen. Here are both, each lifting a barrier.
play sound until done
when program starts
play sound Communication / Hello until done
A run clockwise for 1 rotations
start sound
start sound Communication / Hello
A run clockwise for 1 rotations
0.0suntil done0.0sstart sound
until done: warn first, then movestart sound: warn while moving
Two programs. Same sound, same movement — only the sound block is different.
Watch the barriers, not the clock. On the left the warning finishes before anything moves; on the right it sounds while the barrier lifts.
The bars underneath are when the speaker was on and when the motor was turning. On the left they never overlap: the program is stuck at the sound block until the file has finished, and only then does the barrier lift. On the right they overlap almost completely, and the whole job is done in half the time.
- play sound until done — everything stops and waits. Use it for a warning that must be heard before something moves.
- start sound — the sound and the movement happen together. Use it when the noise belongs to the movement, like a motor whirring as an arm lifts.
Why it matters
Real machines warn before they move, not after: a lift chimes before the doors close, a reversing lorry beeps while it rolls back, a level crossing sounds before the barrier drops. Getting the order right is the difference between a warning and an apology.
Say this back before moving on: “Same blocks, different order, different show.”
What’s in this build 4 min
| Part | What it is doing here |
|---|---|
| EV3 Intelligent Brick | Runs the show, and is the body of the dinosaur. Its weight is part of the balance — move it and the T-Rex’s walk changes. |
| Medium Motor — the legs | Drives both legs through one linkage, so a single motor makes two feet take turns. One rotation is one full stride. |
| The Brick screen | Part of the performance, not a debug tool. It is how the show tells the audience what is happening. |
| The status light | The cheapest drama in the whole kit. Red during a roar reads as danger without a word being said. |
| The tail (not electronic) | The counterweight. Without it the head wins and the model tips forward on the first step. |
Check it stands before you make it walk
- Stand the T-Rex on a flat table and let go. Does it stay up on its own two feet?
- Push the head gently down with one finger and let go. It should come back up. If it stays down, the tail is too light or too short.
- Turn the motor by hand through one full rotation and watch the feet. You should get one clean stride, with each foot leaving the table in turn.
- Watch for the linkage catching at any point in the rotation. A catch becomes a stall the moment the motor is driving it.
Ports — and the rule 4 min
Sensors go in ports 1, 2, 3, 4. Motors go in ports A, B, C, D. They are not interchangeable, and nothing will tell you politely if you swap them.
| Part | Port | Why this one |
|---|---|---|
| Leg motor (Medium) | A | A single job motor, not half of a driving pair — so it takes a Motor block on A rather than the Movement blocks. |
| Sensors | none | The T-Rex cannot see, hear or feel anything. It performs the same show to an empty room, which is worth remembering when you reach the mission. |
Check your own build now:
- Leg motor into A.
- Route the cable along the tail rather than under the body — a cable beneath a walking model lifts a foot off the table.
- Leave a clear run of about 30 cm in front of it. It walks slowly, but it does walk.
Connect the Brick 4 min
Two routes, and either is fine. USB is the reliable one and the one to fall back on when a room’s Bluetooth is busy; Bluetooth leaves the robot free to move, which some models need.
How to connect the BrickUSB and Bluetooth, step by step, with a photograph of every screen. Open it if you have not done this before — or if pairing is not working.Show meHide
USB — the reliable one
- Switch the Brick on with the dark grey centre button.
- Cable into the Brick’s PC port — the small square socket beside the numbered ports, not one of the numbered ones.
- Other end into the computer.
Bluetooth — name it first
Do these in order. Naming the Brick after you go looking for it in the list is how groups end up driving each other’s robots.
- Name your Brick. On the Brick: Settings (the spanner) → Brick Name. Type something nobody else will pick, then press the tick. Every Brick is called
EV3until somebody changes it. - Turn Bluetooth on. Settings → Bluetooth. Tick Bluetooth and Visibility. Leave iPhone/iPad/iPod unticked.
- Connect from EV3 Classroom. Click the Brick icon at the top of the programming area, find your Brick by name, and click Connect.
- Say yes on the Brick. It asks “Connect?” with the computer’s name — choose the tick, then accept the passkey, which is already 1234.
EV3.The two failures, every class, every time. The Brick has gone to sleep while you were building — press the centre button to wake it. Or you have paired with the group at the next table, which is why the name matters.
The long version, including Port View and how to read the port tiles, is in the Brick & Bluetooth guide.
Bluetooth if you can. This model walks, and a USB cable trailing off one side pulls it off its line — which on a two-legged model is the difference between striding and toppling.
Confirm the connection 2 min
- Check the Brick icon: connected, or not.
- One Medium Motor tile on A, and nothing in ports 1–4. If the tile shows a Large Motor, the wrong motor is in the model and the legs will be geared wrongly.
- Turn a leg by hand and watch tile A count.
- Set the volume somewhere sensible before you start. A room of roaring dinosaurs at full volume is nobody’s friend.
Make it move 10 min
The first show: announce it, turn the light red, roar up the scale, then stomp forward.
when program starts :: events hat write [ROAR] at line (1) :: display set status light to [red v] :: display play beep (40) for (0.2) seconds :: sound play beep (55) for (0.2) seconds :: sound play beep (70) for (0.2) seconds :: sound [A v] run [clockwise v] for (2) [rotations v] :: motors
- write ROAR at line 1 — the show has a title before anything happens.
- set status light to red — instant, and it stays red for the rest of the run.
- three beeps, 40 → 55 → 70 — 0.6 seconds of rising growl. Each block waits for the one before, which is exactly why they sound like one noise rather than three.
- run for 2 rotations — two strides, after the roar has finished.
What success looks like: a title on screen, a red light, a growl that climbs, and then a dinosaur walking towards you. In that order, every time.
If it roars while it walks, you have put the motor block above the beeps. Nothing is broken — but you have made the other show, and you have just proved the point of the lesson.
Change it and test 8 min
Every change below is a reordering or a small addition. Run the show after each one and decide, out loud, whether it is better or worse — that judgement is the skill.
- Move the motor block to the top, above the screen. The T-Rex arrives, then announces itself. Which is more frightening?
- Lower every note by 10 — 30, 45, 60. A bigger animal, or a smaller one?
- Add two more beeps after the top note, coming back down: 40, 55, 70, 55, 40. Longer, and more like a real roar.
- Put a
wait (1) secondsbetween the walk and the roar. One second of a dinosaur standing still doing nothing. Watch how much that empty second adds. - Add
set status light to [green v]as the very last block, so the show ends calm. Now run it twice in a row and watch what the light does at the start of the second run.
Step 4 is the one worth keeping. The most effective thing in the whole show is the moment where nothing happens at all — and wait is the only block in this lesson that produces nothing.
Step 5 sets up the third challenge. The light is still red when the second run begins, because nothing told it to go back — and a show that opens differently the second time is not finished.
Silence is a block. So is stillness. Use them on purpose.
