R09-U1 · usually age 9 · Robot Explorers

Programs and Patterns

How do we avoid repeating instructions?

Pilot unit plan · 5 sessions · not yet classroom-validated

Build: Animated wearable badge

Block programs on a micro:bit: blocks run in order, a “forever” block and a “repeat” block run others again, and an event waits for a button. Each idea is tried in MakeCode's simulator first, then on the real board, and the unit ends with an animated badge the learner changes on purpose and explains.

Decide

Who it is for

Age is a starting point, never a limit. A learner who can show what this unit starts from can begin here at any age.

How they learn: By arranging instruction cards or blocks, predicting what happens, and testing on a kit. Short sentences, with words and pictures together.
The adult's role: An adult oversees circuits, batteries and motors.
Session: 60–75 minutes
Hardware: micro:bit with MakeCode, or a similar child-friendly board. Start in the board's own simulator. A micro:bit is 3.3 V: never connect a 5 V signal straight to it.

Starts from

Repeat
Use 'repeat' instead of writing the same steps again.
Built in R08-U2 Make It Move with Blocks
Events
Make something start when something happens (an event).
Built in R08-U1 Input, Output and Events

Builds, and what it is the input for

Block programs
Build and change a block program with sequences, loops and events.
Input for R09-U2 Sense the World, R09-U4 Smart Crossing

In the studio today

Activity: Robot Blocks (levels 1–2)

Sessions

Session 1 · 60 min
In what order do blocks run?
A block program is a sequence: blocks snapped together run from the top down. The “show leds” block draws a picture; the “forever” block keeps running the blocks inside it. The simulator only: nothing is plugged in.
The adult says first: “Blocks are instructions. They run in order, top to bottom. Let's guess, then test.”
Learner card
1. Drag “show leds” into “forever”.
2. Draw a big heart.
3. Draw a small heart below it.
4. Guess: which shows first?
5. Watch the simulator.
6. Change the order. Guess again.
Key words (show each with a picture): block · order · forever
Timing (27 of 60 min at the screen)
1. 15 minAway from the screen: Picture-card acting: each learner holds one picture; the group stands in order and the adult reads the line from the top, then back to the start. Guess, then swap two cards and read it again.
2. 15 minAt the screen: MakeCode: the Flashing Heart steps, two “show leds” pictures in “forever”. Guess which shows first, then watch the simulator.
3. 10 minAway from the screen: On a 5 × 5 paper grid: draw a third picture and plan a new order, with a guess.
4. 12 minAt the screen: Build the third picture, change the order, guess, then run it.
5. 8 minAway from the screen: Fill in the table; say which block runs first and what “forever” does.
In the studio
No studio lab or activity.
Outside the studio: MakeCode editor and its micro:bit simulator (makecode.microbit.org)
Hands-on
Nothing is powered: this session uses the simulator only. First, away from the screen, the group acts a program out with picture cards: each learner holds one picture, they stand in order, and the adult reads the line from the top, then goes back to the start, as “forever” does. Then the adult opens MakeCode and the Flashing Heart tutorial and reads each step aloud. The learner drags a “show leds” block into the “forever” block and clicks squares to draw a big heart, then a second “show leds” block below it with a small heart. Before the simulator runs it, the learner says which picture shows first. Then the learner draws a third picture on a paper grid, builds it, changes the order of the three blocks, and predicts again before each run.
Starting blocks: MakeCode tutorial “Flashing Heart” (makecode.microbit.org/projects/flashing-heart): a “show leds” block inside “forever”.
Evidence to collect
A prediction for each order, a short test table (Order of pictures | My guess | What showed) for three orders, filled in by the learner, and the learner's spoken explanation of which block runs first and what “forever” does.
Test table columns: Order of pictures | My guess | What showed
Predict
Before each run, the learner points to the picture that will show first, then the one after it.
Debug
If the simulator shows nothing, check that each “show leds” block is snapped inside “forever”, not loose beside it.
Reflect
What would change if there were no “forever” block?
Works towards: Block programs
Session 2 · 60 min
How can one block repeat other blocks?
The “repeat” block runs the blocks inside it a set number of times, then the program goes on. In Robot Blocks, one step of a pattern is found and repeated, and a repeat goes inside a repeat. In MakeCode, a heart flashes a counted number of times.
The adult says first: “A repeat does the same blocks again. Count with me.”
Learner card
1. Find one step.
2. Put it in a repeat.
3. Guess how many flashes.
4. Run it. Count out loud.
5. Change the number. Guess again.
Key words (show each with a picture): repeat · times · pause
Timing (30 of 60 min at the screen)
1. 10 minAway from the screen: Body repeats: clap and step a pattern from picture cards, find the one step that repeats, and say how many times.
2. 15 minAt the screen: Robot Blocks level 1, one step inside a repeat; level 2, a repeat inside a repeat.
3. 10 minAway from the screen: On paper: draw the path each repeat made, and guess how many flashes a heart repeated 4 times gives.
4. 15 minAt the screen: MakeCode: the “repeat” block with the heart in “on start”. Guess, run, count out loud, change the number.
5. 10 minAway from the screen: Fill in the table; say what the number on “repeat” changes.
In the studio
- Robot Blocks (levels 1–2)
Outside the studio: MakeCode editor and its micro:bit simulator (makecode.microbit.org)
Hands-on
Nothing is powered. First the group claps and steps a pattern from picture cards and finds the one step that repeats. In Robot Blocks level 1, the learner finds one step of the stairs and puts it inside a repeat; in level 2, a repeat goes inside a repeat, and the learner points to the part of the path each one makes. Then in MakeCode's simulator: a “repeat” block (it reads “repeat 4 times”) inside “on start”, holding “show icon” (heart), “pause (ms)” 300, “clear screen” and “pause (ms)” 300. The learner predicts the number of flashes, runs it, counts out loud, then changes the number and predicts again.
Starting blocks: Built from scratch: a “repeat” block from Loops inside “on start”, holding “show icon” (heart), “pause (ms)” 300, “clear screen” and “pause (ms)” 300, like MakeCode's repeat example.
Evidence to collect
A prediction for each number, a short test table (Repeat number | My guess (flashes) | Flashes counted) for three numbers, and the learner's spoken explanation of what the number on “repeat” changes.
Test table columns: Repeat number | My guess (flashes) | Flashes counted
Predict
Before each run, the learner says how many flashes the number on “repeat” will give.
Debug
If the count seems off by one, slow it down (bigger “pause (ms)” numbers) and count again out loud with the adult.
Reflect
Where did a repeat save you blocks today, in Robot Blocks and in MakeCode?
Works towards: Block programs
Session 3 · 75 min
How does a program wait for a button?
Events: the “on button A pressed” block runs its blocks when button A is pushed and let go. First in the simulator (click its on-screen buttons), then on the real micro:bit, downloaded from MakeCode and then run from its battery pack.
The adult says first: “Now the program waits for you. A button press is an event.”
Learner card
1. Drag “show icon” into “on button A pressed”.
2. Pick a happy face.
3. Do the same for B.
4. Guess, then press.
5. Hold A for three. What happens?
Key words (show each with a picture): event · button · download
Timing (25 of 75 min at the screen)
1. 10 minAway from the screen: Act out an event: one learner waits and shows a happy-face card only when a partner taps their shoulder.
2. 15 minAt the screen: MakeCode: the Smiley Buttons tutorial; guess, then click the simulator's A and B.
3. 10 minAway from the screen: Write guesses for A, B and a long hold on A in the table.
4. 10 minAt the screen: Plug in USB and download; wait until the light on the back stops flashing.
5. 20 minAway from the screen: The real micro:bit: press A and B; then the battery pack (the adult fits it), and a long hold on A.
6. 10 minAway from the screen: Fill in the table; say what an event is.
In the studio
No studio lab or activity.
Outside the studio: MakeCode editor and its micro:bit simulator (makecode.microbit.org)
Hands-on
First, away from the screen, the group acts out an event: one learner waits, and shows a happy-face card only when a partner taps their shoulder. In the simulator next: the learner follows the Smiley Buttons tutorial, so button A shows a happy face and button B a sad face, and clicks the simulator's buttons. Then the learner plugs the real micro:bit into the computer with its USB cable and downloads the program. The learner presses the real buttons. Next the learner unplugs USB and the adult plugs in the battery pack: the program is still there. Last, the learner presses and holds A for a slow count of three, then lets go, and says what happened.
Starting blocks: MakeCode tutorial “Smiley Buttons” (makecode.microbit.org/projects/smiley-buttons): “show icon” inside “on button A pressed”.
Evidence to collect
A prediction for each button, a short test table (Button | My guess | What showed) for A, B and a long press on A, in the simulator and on the real micro:bit, and the learner's spoken explanation of what an event is.
Test table columns: Button | My guess | What showed
Predict
Before pressing, the learner says what A, B and a long hold on A will show.
Debug
If a long press shows nothing, that is the block's rule: it runs when the button is pushed and let go within 1 second.
Reflect
What is different about a program that waits for you?
⚠ Adult checks before power-on: Nothing metal touches the micro:bit or its gold pins along the bottom edge (no coins, keys, foil, metal clips or jewellery): metal across the pins can short the power. Hands holding the board are fine. The learner plugs in the USB cable, gripping the plug, while the adult watches; only the adult fits or unplugs the battery pack.
Works towards: Block programs
Session 4 · 75 min
Can my badge play animations when I ask?
The prototype, an animated wearable badge: “on start” shows a still picture; button A plays one animation and button B another, each a “repeat” holding “show leds” pictures with “pause (ms)” between them. Designed in the simulator, then downloaded and worn.
The adult says first: “Today you design a badge. Loops make it move. Buttons choose what plays.”
Learner card
1. Make two animations.
2. Put each in a repeat.
3. Button A plays one.
4. Button B plays the other.
5. Test in the simulator first.
Key words (show each with a picture): animation · repeat · event
Timing (25 of 75 min at the screen)
1. 10 minAway from the screen: Sketch two animations and a still picture on paper 5 × 5 grids.
2. 15 minAt the screen: Build them in the simulator: each a “repeat” of “show leds” pictures with “pause (ms)”; try A and B.
3. 10 minAway from the screen: Make the card badge: a plastic clip or a safety pin through the card only (the adult fits it).
4. 10 minAt the screen: Plug in USB and download; wait until the light on the back stops flashing.
5. 20 minAway from the screen: The adult fits the battery pack; tape the board to the badge, gold pins covered; wear it and test A and B.
6. 10 minAway from the screen: Fill in the table; say which part repeats and which part waits.
In the studio
No studio lab or activity.
Outside the studio: MakeCode editor and its micro:bit simulator (makecode.microbit.org)
Hands-on
The learner sketches two animations on paper, then builds them in the simulator first: each a “repeat” of two or three “show leds” pictures with “pause (ms)” between them, on A and B, and a still picture in “on start”. The learner downloads it; the adult fits the battery pack and tapes its cover shut. The micro:bit and pack are taped to a card badge, held by a plastic clip or a safety pin through the card only, with tape over the gold pins.
Starting blocks: The learner's own blocks from sessions 2 and 3: the “repeat” from session 2 and the “on button A pressed” event from session 3.
Evidence to collect
A prediction for each button, a short test table (Button | My guess | What it did) in the simulator and on the worn badge, and the learner's spoken explanation of which part repeats and which part waits for a button.
Test table columns: Button | My guess | What it did
Predict
Before each press, the learner says which animation will play and how many times.
Debug
If a press seems to do nothing, check the letter on the event block (A or B) and that the animation sits inside it.
Reflect
Which part of your badge repeats, and which part waits for you?
⚠ Adult checks before power-on: Nothing metal touches the micro:bit or its gold pins along the bottom edge (no coins, keys, foil, metal clips or jewellery): metal across the pins can short the power. Hands holding the board are fine. The learner plugs in the USB cable, gripping the plug, while the adult watches; only the adult fits or unplugs the battery pack. Badge: nothing metal touches the micro:bit or its pins. Hold the badge with a plastic clip, or a safety pin through the card only, well away from the board, and tape over the gold pins along the bottom edge. The badge is worn on the outside of clothing, never on a cord around the neck; the pack's cover is closed and taped.
Works towards: Block programs
Session 5 · 60 min
Can I change my badge on purpose and explain it?
Changing a block program on purpose: one change at a time to a loop (its number, or the “pause (ms)” inside it), predicted first, tried in the simulator, then on the real badge.
The adult says first: “Change one thing. Guess first. Then test.”
Learner card
1. Pick one loop.
2. Change one number.
3. Guess what will change.
4. Test in the simulator.
5. Test on your badge.
6. Tell why it changed.
Key words (show each with a picture): change · loop · guess
Timing (20 of 60 min at the screen)
1. 10 minAway from the screen: Choose one change to a loop and write the guess.
2. 10 minAt the screen: Try it in the simulator, then plug in USB and download it.
3. 15 minAway from the screen: Test the real badge; fill in the table.
4. 10 minAt the screen: A second change: the simulator, then download.
5. 15 minAway from the screen: Test it, then show the badge to the adult and explain both changes.
In the studio
No studio lab or activity.
Outside the studio: MakeCode editor and its micro:bit simulator (makecode.microbit.org)
Hands-on
The learner chooses one change to a loop in the badge, for example the number on “repeat” or a “pause (ms)” value, and says what will look different. They try it in the simulator first; then they plug the badge's micro:bit into USB, download it and unplug USB; the adult fits the battery pack if it is off, and the learner tests the real badge. They make a second change, predicted and tested the same way. Finally they show the badge to the adult and explain both changes.
Starting blocks: The learner's own badge blocks from session 4.
Evidence to collect
The unit's evidence: the learner uses a loop in the badge program and explains a changed behaviour: a prediction for each of two changes to a loop, a short test table (My change | My guess | What changed), and the learner's spoken or written explanation of why the behaviour changed.
Test table columns: My change | My guess | What changed
Predict
Before downloading a change, the learner says exactly what will look different.
Debug
If the change does not show on the badge, check that the new version was downloaded after the last change.
Reflect
Which change was easiest to predict, and why?
⚠ Adult checks before power-on: Nothing metal touches the micro:bit or its gold pins along the bottom edge (no coins, keys, foil, metal clips or jewellery): metal across the pins can short the power. Hands holding the board are fine. The learner plugs in the USB cable, gripping the plug, while the adult watches; only the adult fits or unplugs the battery pack.
Works towards: Block programs

Materials

Per pair: a BBC micro:bit and its USB cable (USB micro-B at the micro:bit end)
A computer with a web browser for MakeCode (makecode.microbit.org); no installs needed
Kept by the adult: the micro:bit battery pack with 2 × AAA zinc or alkaline cells; no rechargeable cells, Li-ion, LiPo, RC or coin-cell packs
Pencils and paper for the test tables
Card, sticky tape and a plastic clip or a safety pin for the badge holder (the adult fits the pin, through the card only)

⚠ Safety before any session

Batteries: only the micro:bit's 2 × AAA pack with zinc or alkaline cells, or USB from a computer; no rechargeable cells, power banks, Li-ion, LiPo, RC packs or coin cells.
Cells: the adult fits two new cells of the same type, the right way round, never mixes new and used cells, and takes spent cells out of the pack.
The official pack has no on/off switch: to switch off, the adult unplugs it, gripping the connector's base and wiggling it gently, never forcing it.
Nothing is connected to the micro:bit's pins in this unit. Never connect a 5 V signal or supply to a micro:bit's pins or battery socket: it runs at 3.6 V at most.
Badge: nothing metal touches the micro:bit or its pins. Hold the badge with a plastic clip, or a safety pin through the card only, well away from the board, and tape over the gold pins along the bottom edge.
The badge is worn on the outside of clothing, never on a cord around the neck, and only during the session.
If the micro:bit or its pack gets warm: don't touch it; tell the adult, who unplugs it.

Safety for every band

Low voltage only: battery packs or USB. Never mains electricity.
Never connect a motor straight to a controller pin: use a driver and a separate supply.
Every moving robot has a power-off switch within reach that cuts the motor battery (or all power). A software stop button is extra, never a replacement.
No coin or button cells and no loose small magnets; battery compartments screwed shut.
Guard wheels and moving parts against pinched fingers; keep robots slow and indoors.
No exposed lithium cells, improvised chargers or lasers.
No Li-ion, LiPo or RC packs: AA alkaline or NiMH cells in a closed holder with a switch, or USB.
Check polarity and voltage before power-on; a 3.3 V board must not receive 5 V signals.

Notes for the adult

Read each step aloud first: your words come before the learner's card. The card uses short sentences; show each key word with a picture.
These plans assume one adult for up to four pairs. Learners plug the USB cable into their own computer, gripping the plug, while the adult watches; only the adult handles cells and battery packs. With more pairs, add an adult or bring fewer pairs to the real board at once.
Each session's timing keeps screen time to short bursts (15 minutes at most), with building, acting or testing away from the screen between them.
Before the first session on the real board, set up each computer and test a download: either pair each micro:bit once with WebUSB (then MakeCode's Download button sends the program straight to it), or download the .hex file and drag it onto the MICROBIT drive. The light on the back flashes while the program copies: unplug only after it stops.
The MakeCode simulator and Robot Blocks prepare the work. Only the real micro:bit, seen working by the adult, counts as evidence: a simulator run is never physical success.
Hand out each session's test table with its columns ready: the learner fills it in, and the adult writes only for a learner who needs it. Making their own tables is taught in R09-U3.
The studio's Arduino labs are written for ages 12 and up and are not used in this unit. Robot Blocks also shows each program as Arduino-style code: point to the blocks, not the code.
Readiness decides, not age: a learner who already builds and changes block programs with loops and events can move on to R09-U2.
The badge shows patterns and pictures, not the learner's name.

Planned studio features

Not built yet. The unit runs without them.

A micro:bit-style blocks simulator in the studio (today the unit uses MakeCode's own simulator and Robot Blocks).
Printable picture cards for each session's key words, and printable learner cards.
A printable test-table sheet for each session, with its columns.

Sources

The facts this plan relies on, in each source's own words.

Microsoft MakeCode for micro:bit: Simulator
“The JavaScript simulator allows you to test and execute most BBC micro:bit programs in the browser. It allows you to emulate sensor data or user interactions.”
Microsoft MakeCode for micro:bit: Transferring programs (USB)
“Most of the time you'll be writing and testing your programs in the simulator. … Click Download to download the .hex file.”
Microsoft MakeCode for micro:bit: WebUSB (pairing for one-click downloads)
“The first time you pair your micro:bit with your computer you’ll need to go through a few easy steps to get setup. … Once your micro:bit is paired, MakeCode will use WebUSB to transfer the code directly and you won’t have to drag and drop .hex files from a folder.”
Microsoft MakeCode for micro:bit: Transferring with Chrome on Windows (the .hex file)
“In File Explorer, drag and drop the .hex file from the download folder onto the MICROBIT drive. … The LED on the back of your micro:bit flashes during the transfer (which should only take a few seconds). … To rerun your program, press the reset button on the back of your micro:bit.”
Microsoft MakeCode for micro:bit tutorial: Flashing Heart
“Code the lights on the micro:bit into a flashing heart animation! … Drag the show leds block into the forever block. Then in the show leds block, click on the squares to draw a heart design.”
Microsoft MakeCode for micro:bit tutorial: Smiley Buttons
“Click on the Basic category in the Toolbox. Drag a show icon block into the on button A pressed block.”
Microsoft MakeCode for micro:bit reference: forever
“Keep running part of a program in the background.”
Microsoft MakeCode for micro:bit reference: Repeat
“Run part of the program the number of times you say. … Flash the heart icon on the screen 4 times.”
Microsoft MakeCode for micro:bit tutorial: Blow Away (the repeat block)
“From the Loops category, find the repeat [4] times loop and snap it into your empty forever container.”
Microsoft MakeCode for micro:bit reference: On Start
“The on start is a special event that runs when the program starts, before any other event.”
Microsoft MakeCode for micro:bit reference: On Button Pressed
“Start an event handler (part of the program that will run when something happens, like when a button is pressed). … For button A or B: This handler works when the button is pushed down and released within 1 second.”
Microsoft MakeCode for micro:bit reference: Show Icon
“This program shows a happy face and then a sad face with the show icon function, with a one second pause in between. … interval (optional), the time to display in milliseconds. default is 600.”
Microsoft MakeCode for micro:bit reference: Pause
“Pause the program for a duration of the number milliseconds you say. … To convert from seconds: 100 milliseconds = 1/10 second and 1000 milliseconds = 1 second.”
Microsoft MakeCode for micro:bit source code: libs/core/basic.cpp (block names)
“block="show leds" … block="clear screen" … block="forever" … block="pause (ms) %pause"”
Microsoft MakeCode for micro:bit source code: libs/core/input.cpp (block names)
“block="on button|%NAME|pressed" … block="button|%NAME|is pressed" … block="acceleration (mg)|%NAME" … block="light level" … block="temperature (°C)"”
Microsoft MakeCode for micro:bit source code: libs/core/icons.ts (icon and block names)
“block="heart" … block="no" … block="stick figure" … block="show icon %i"”
micro:bit Foundation support: Connecting a power supply to the micro:bit
“Usually, you will need a USB type-A plug at one end, and a USB micro-B plug for the other end, to be plugged into the micro:bit. … In addition to USB powering, the BBC micro:bit can also be powered using a battery pack containing 2 x zinc or alkaline AAA batteries. … To insert the battery connector, grip the base of the connector between your thumb and forefinger and push the connector into the JST socket on the board. To remove the battery connector you may need to wiggle the connector to release. … also has a power saving mode that helps you conserve battery power, meaning that you may not have to disconnect the battery pack between uses. Hold down the power/reset button to enter/exit this mode. … Please do not mix different types of batteries or mix new and used batteries … Please insert the batteries the correct way round (with the correct polarity) … Please remove spent batteries form the battery holder … Do not short-circuit the battery supply terminals, for example by placing a metal object across the terminals … Only use Zinc or Alkaline batteries with your BBC micro:bit … If you find it difficult to remove the battery pack, please do not force it. … Please do not plug your micro:bit directly into the mains or into a portable charger. They supply a voltage stronger than the micro:bit can safely handle.”
micro:bit Foundation: micro:bit battery pack (the maker's product notes)
“Official brand micro:bit battery pack. This option does not include an on/off switch. … 2x AAA Battery enclosure”
micro:bit Foundation technical docs: Power supply
“This table implies an operating voltage range of the micro:bit device as a whole as being 1.7V min and 3.6V max. … It is advised that you do not power the micro:bit from USB battery packs.”
micro:bit Foundation technical docs: Edge connector (nRF52 GPIO table)
“KEY | Description | section | Min | Max … VIO≤3.6 | Tolerable pin voltages for IO pin with VDD ≤3.6 | 9 | -0.3V | VDD+0.3”
Microsoft MakeCode for micro:bit: micro:bit pins (the power pins)
“Watch out! The pins labelled 3V and GND relate to the power supply of the board, and they should NEVER be connected together.”

Programs and Patterns

Who it is for

Starts from

Builds, and what it is the input for

In the studio today

Sessions

In what order do blocks run?

How can one block repeat other blocks?

How does a program wait for a button?

Can my badge play animations when I ask?

Can I change my badge on purpose and explain it?

Materials

⚠ Safety before any session

Notes for the adult

Planned studio features

Sources