Arduino Learning Studiorobotics pathway

R10-U1 · usually age 10 · Robot Explorers

Power a Moving Machine

What makes a motor turn?

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

Build: Safe motorised spinner

A motor turns only when a battery pushes current through it; the micro:bit only tells the motor board how fast. Learners trace the power path, test a clamped, guarded card spinner at speeds they predict (never above 50 of 100), started on button A and stopped by the adult at the board's switch, and end by describing the power path and testing safe operation.

  • Act
  • Power and safety

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

Builds, and what it is the input for

In the studio today

No studio lab or activity for this unit yet.

Sessions

  1. Session 1 · 60 min

    What makes a motor turn, and what tells it to?

    Power and signal. A motor turns only when a battery pushes current through it. On our kit the battery's power goes through the robotics board to the motor; the micro:bit, powered by the board, sends only a small signal that tells the board how fast. The parts are looked at, not connected, and the simulator shows only the display.

    The adult says first: “A motor needs power to turn. The micro:bit only sends a signal.”

    Learner card

    1. Turn the motor shaft by hand.
    2. Power comes from the battery.
    3. The signal comes from the micro:bit.
    4. Sort each card: power or signal?
    5. Guess, then say why.

    Key words (show each with a picture): motor · power · signal

    Timing (10 of 60 min at the screen)

    1. 15 minAway from the screen: Look and feel: turn an unconnected motor's shaft by hand; find the board's motor terminals, switch and sockets.
    2. 15 minAway from the screen: Card sort: power path or signal path, with a guess and a reason for each card.
    3. 10 minAt the screen: MakeCode: the adult's blocks in the simulator. The number shows; A and B turn nothing.
    4. 10 minAway from the screen: Cut and mark the card disc; say what the real spinner will do on A and on B.
    5. 10 minAway from the screen: Fill in the table; say which parts carry the power and which sends the signal.

    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 picture cards, unconnected parts and the simulator only. First, away from the screen, each pair turns the shaft of an unconnected TT motor slowly by hand and feels the gearbox, then finds the robotics board's motor terminals, its on/off switch and its servo sockets, connecting nothing. The group sorts picture cards (battery, holder switch, board, motor, micro:bit, USB cable) onto a power path and a signal path, with a guess and a reason for each card. Then the adult opens MakeCode with the board's extension added and shows the adult's blocks: “on start” holding “turn off Motor 1” and “show number” 30; “on button A pressed” holding “Motor 1 on direction … speed …” set to Forward and 30; and “on button B pressed” holding “turn off Motor 1”. MakeCode's simulator has no robotics board: the board's motor and servo blocks run there but move nothing, so the simulator checks only what the display shows. The learner says what the real spinner will do when A is pressed, and when B is. Last, each pair draws round a cup on thin card, cuts out a disc at most 10 cm across with safety scissors, rounds its edge and draws a mark near the edge.

    Starting blocks: Built from scratch: the adult builds “on start” holding “turn off Motor 1” and “show number” 30, “on button A pressed” holding “Motor 1 on direction … speed …” set to Forward and 30, and “on button B pressed” holding “turn off Motor 1”; the learner changes only the numbers and the direction in this unit.

    Evidence to collect

    A prediction for each card, a short test table (Card | My guess | Why) for six cards, filled in by the learner, and the learner's spoken explanation of which parts carry the power and which part sends the signal.

    Test table columns: Card | My guess | Why

    Predict
    Before the simulator runs, the learner says what it will show, and whether anything will turn when A is pressed.
    Debug
    If a card fits neither path, ask: does it carry the battery's push, or only a message about what to do?
    Reflect
    Why can the micro:bit tell the motor what to do but not make it turn?

    Works towards: Power vs signal

  2. Session 2 · 75 min

    Where does the motor's power go?

    The power path, tested: battery, the holder's switch, the board's terminal block and on/off switch, the board's motor driver, Motor 1's terminals, the motor, and back through the ground that every part shares. The micro:bit, powered by the board, sends the signal. Break the path and the motor cannot turn, even when the signal is sent.

    The adult says first: “Today we follow the power. Battery, board, motor. The micro:bit only sends the signal.”

    Learner card

    1. Stay outside the taped zone.
    2. Call “Stop!” if anything looks wrong.
    3. Guess: will the disc turn?
    4. Trace the path with your finger.
    5. Battery, board, motor, back.

    Key words (show each with a picture): power path · switch · ground

    Timing (10 of 75 min at the screen)

    1. 15 minAway from the screen: The rig with the board off and outside the zone: trace the power path with a finger.
    2. 10 minAt the screen: The adult's blocks in the simulator (A and B turn nothing there); download to your own micro:bit.
    3. 10 minAway from the screen: The stop drill: who calls “Stop!”, who switches off, and where everyone stands.
    4. 25 minAway from the screen: Three runs on the one rig for the whole group, each predicted: the whole path; the holder switched off; both motor leads out, capped and taped down (board off first).
    5. 15 minAway from the screen: Fill in the table; trace the power path aloud.

    In the studio

    No studio lab or activity.

    Outside the studio: MakeCode editor and its micro:bit simulator (makecode.microbit.org)

    Hands-on

    Before the session, with the board and the holder switched off, the adult builds the spinner rig: the motor fixed in its mount on a wooden base with its shaft pointing up, a wheel hub on the shaft with the card disc taped flat on it, a card guard wall round the disc, and the base clamped to the table in the middle of the safe zone, taped 40 cm across; the board and the holder sit outside the zone on the adult's side, and the motor's leads, long enough to reach, go into the Motor 1 terminals while everything is switched off. In the simulator first, each pair checks that the adult's blocks show 30 and that A and B turn nothing there; then each pair downloads them (the board switched off, the micro:bit out of the board, USB in; USB out once the light on the back stops flashing, the micro:bit back in). The adult runs three runs on the rig for the whole group, with one pair's micro:bit, and the learners predict each one from outside the zone. Run 1: the stop drill; the adult switches on, the number slides across, the adult presses A and the disc turns; B stops it; then someone calls “Stop!”, and the adult switches the board off. Run 2: the holder is switched off at its own switch; the stop drill; the adult switches the board on: everything stays dark, the micro:bit too, and A does nothing. Run 3: with the board and the holder switched off, the adult takes both motor leads out of the Motor 1 terminals, caps each bare end with tape and tapes both down to the base, away from the board; the stop drill; the adult switches on and presses A: the number shows, the disc stays still; then the board is switched off and both leads go back in.

    Starting blocks: Built from scratch: the adult's blocks from session 1 (“on start” holding “turn off Motor 1” and “show number” 30, “on button A pressed” holding “Motor 1 on direction … speed …” set to Forward and 30, and “on button B pressed” holding “turn off Motor 1”).

    Evidence to collect

    A prediction for each run, a short test table (Test | My guess | What happened) for the three runs, and the learner's spoken explanation of the power path, from the battery through the board to the motor and back, and of what the signal does.

    Test table columns: Test | My guess | What happened

    Predict
    Before each run, the learner says whether the disc will turn and whether the display will light.
    Debug
    If nothing lights at all, check the holder's switch and the board's switch first: the battery powers the micro:bit too.
    Reflect
    Which part of the path does the signal never touch?

    ⚠ Adult checks before power-on: Nothing metal touches the micro:bit, its gold pins or the board, and nothing metal lies under it. Before the adult switches on: the micro:bit is firmly in the board, display facing the Link header, its own battery pack and USB unplugged; both switches were off while anything was plugged in or moved. The board's battery is the motor battery: it reaches the motor only through the holder's switch, the board's on/off switch (the power-off switch) and its Motor 1 terminals. Clamp first: the motor is screwed into its mount and the base clamped or taped to the table before the board is switched on. The motor starts only on button A, but a wrong download could start it at once. The spinner is a disc of thin card at most 10 cm across, edges rounded, nothing sharp or loose on it, spinning flat (shaft up) below the top of a card guard wall 2 cm out from it, in a safe zone taped 40 cm across. The safe zone reaches more than 10 cm beyond the guard wall. The board and the holder sit outside it on the adult's side, with motor leads long enough to reach. Fingers, hair, sleeves and cords stay outside the safe zone while the board is on; long hair is tied back. Nobody leans over the zone: watch from outside it, looking down, eyes never level with the disc. Speed limit: the spinner's speed number is never above 50 (of 100). Before each switch-on, the stop drill: someone calls “Stop!” and the adult at the board's switch shows it going off. In a run, on “Stop!” the adult switches off at once; learners never reach into the zone. Rewire only when unpowered: the board and the holder are switched off before any wire, motor, servo or sensor is plugged in, moved or taken out.

    Works towards: Power vs signal

  3. Session 3 · 75 min

    How does the number change the speed?

    The board's motor block takes a speed from 0 to 100: a bigger number turns the motor faster. Speeds 25 and 50 are tested by counting the disc's turns for 10 seconds; 50 is the spinner's limit. Is double the number double the speed?

    The adult says first: “The number sets the speed. Guess first. Then count the turns.”

    Learner card

    1. Guess the turns for 25.
    2. Count turns for 10 seconds.
    3. Call “Stop!” from outside the zone.
    4. Now try 50.
    5. Never go above 50.

    Key words (show each with a picture): speed · number · turns

    Timing (15 of 75 min at the screen)

    1. 10 minAway from the screen: Guess the turns in 10 seconds for 25 and for 50.
    2. 10 minAt the screen: Change both numbers to 25; the simulator, then download.
    3. 20 minAway from the screen: Turns at the rig, one pair at a time (about 5 minutes each with the swap): count for 10 seconds; waiting pairs watch from outside the zone.
    4. 5 minAt the screen: Change to 50; the simulator, then download.
    5. 20 minAway from the screen: Turns at 50, the same way; waiting pairs check their guesses.
    6. 10 minAway from the screen: Fill in the table; times 6 for a minute; is double the number double the turns?

    In the studio

    No studio lab or activity.

    Outside the studio: MakeCode editor and its micro:bit simulator (makecode.microbit.org)

    Hands-on

    In the simulator first, the learner changes the number in “show number” and in the motor block to 25 and checks that 25 shows; then the learner downloads it (the board switched off, the micro:bit out of the board, USB in; USB out once the light on the back stops flashing, the micro:bit back in). Pairs take turns at the rig: at each turn the adult, with the board switched off, puts the pair's micro:bit in; the stop drill; the adult switches on and presses A. From outside the safe zone, the learner counts the mark's turns for 10 seconds on the adult's stopwatch; then the learner calls “Stop!”, the adult presses B, and the adult switches the board off. At the pair's next turn, the same for 50, tried in the simulator and downloaded the same way. Never above 50. If the disc hums but does not turn, the adult switches off within a few seconds, and the learner writes it down: it is a result. Last, the learner multiplies each count by 6 for the turns in a minute, and compares 25 with 50.

    Starting blocks: The learner's session 2 blocks (the adult's blocks), with the number changed in “show number” and in “Motor 1 on direction … speed …”.

    Evidence to collect

    A prediction for each speed, a short test table (Speed number | My guess (turns) | Turns (10 s)) for 25 and 50, and the learner's spoken or written explanation of how the number changed the speed, and whether double the number gave double the turns.

    Test table columns: Speed number | My guess (turns) | Turns (10 s)

    Predict
    Before each run, the learner guesses the turns in 10 seconds, and says whether double the number will give double the turns.
    Debug
    If the disc hums but does not turn, the adult switches off within a few seconds: a motor that cannot turn draws its most current (Kitronik gives a stall current of about 1.25 A). Write it down, and never fix it by going above 50.
    Reflect
    Did double the number give double the turns? What does that tell you?

    ⚠ Adult checks before power-on: Nothing metal touches the micro:bit, its gold pins or the board, and nothing metal lies under it. Before the adult switches on: the micro:bit is firmly in the board, display facing the Link header, its own battery pack and USB unplugged; both switches were off while anything was plugged in or moved. The board's battery is the motor battery: it reaches the motor only through the holder's switch, the board's on/off switch (the power-off switch) and its Motor 1 terminals. Clamp first: the motor is screwed into its mount and the base clamped or taped to the table before the board is switched on. The motor starts only on button A, but a wrong download could start it at once. The spinner is a disc of thin card at most 10 cm across, edges rounded, nothing sharp or loose on it, spinning flat (shaft up) below the top of a card guard wall 2 cm out from it, in a safe zone taped 40 cm across. The safe zone reaches more than 10 cm beyond the guard wall. The board and the holder sit outside it on the adult's side, with motor leads long enough to reach. Fingers, hair, sleeves and cords stay outside the safe zone while the board is on; long hair is tied back. Nobody leans over the zone: watch from outside it, looking down, eyes never level with the disc. Speed limit: the spinner's speed number is never above 50 (of 100). Before each switch-on, the stop drill: someone calls “Stop!” and the adult at the board's switch shows it going off. In a run, on “Stop!” the adult switches off at once; learners never reach into the zone. Rewire only when unpowered: the board and the holder are switched off before any wire, motor, servo or sensor is plugged in, moved or taken out.

    Works towards: Motor speed

  4. Session 4 · 75 min

    Which way does it turn, and how slowly can it start?

    Direction and the slowest start: the same block sets Forward or Reverse, so the direction changes in the blocks, never by swapping leads. A still motor and its gearbox can need a bigger number to start than to keep turning: each pair tries one number in Reverse, and the group finds the smallest number that starts the disc.

    The adult says first: “The block also sets the direction. Then we find the slowest start together.”

    Learner card

    1. Guess the way it turns.
    2. Draw the arrow.
    3. Did your number start it?
    4. Call “Stop!” if it hums.
    5. Change the block, not the leads.

    Key words (show each with a picture): direction · Reverse · start

    Timing (10 of 75 min at the screen)

    1. 10 minAway from the screen: Guess: which way will Reverse turn? Which numbers are too small to start?
    2. 10 minAt the screen: Reverse and your pair's number: the simulator, then download.
    3. 25 minAway from the screen: Turns at the rig, one pair at a time (about 5 minutes each): draw the arrow; did it start? Waiting pairs watch from outside the zone.
    4. 15 minAway from the screen: Put the four results in one table; find the smallest number that started it.
    5. 15 minAway from the screen: Say what changed the direction, and why the leads stay as they are.

    In the studio

    No studio lab or activity.

    Outside the studio: MakeCode editor and its micro:bit simulator (makecode.microbit.org)

    Hands-on

    In the simulator first, the learner sets the motor block to Reverse and the pair's own number (the four pairs take 10, 15, 20 and 25) and checks the display; then the learner downloads it (the board switched off, the micro:bit out of the board, USB in; USB out once the light on the back stops flashing, the micro:bit back in). Pairs take turns at the rig: at each turn the adult, with the board switched off, puts the pair's micro:bit in; the stop drill; the adult switches on and presses A. The learner predicts which way the mark will go and whether it will start from still, watches from outside the safe zone, and draws the arrow; then the learner calls “Stop!”, the adult presses B, and the adult switches the board off. If the disc hums but does not turn, the adult switches off within a few seconds. Last, the group puts the four results in one table, finds the smallest number that started the disc, and says what changed the direction since session 3's Forward: the block, not the leads.

    Starting blocks: The learner's session 3 blocks (the adult's blocks), with Reverse and the pair's own number set in “Motor 1 on direction … speed …” and in “show number”.

    Evidence to collect

    A prediction for each number, a short test table (Number (Reverse) | My guess | What it did) for the four pairs' numbers (10, 15, 20 and 25, all in Reverse), and the learner's spoken explanation of what changed the direction and which number started the disc.

    Test table columns: Number (Reverse) | My guess | What it did

    Predict
    Before the pair's turn, the learner draws the arrow they expect and guesses whether the disc will start.
    Debug
    If Reverse turns the same way as session 3's Forward, check that the block was changed and downloaded again; the leads stay as they are.
    Reflect
    Why is it safer to change the direction in the blocks than by swapping leads?

    ⚠ Adult checks before power-on: Nothing metal touches the micro:bit, its gold pins or the board, and nothing metal lies under it. Before the adult switches on: the micro:bit is firmly in the board, display facing the Link header, its own battery pack and USB unplugged; both switches were off while anything was plugged in or moved. The board's battery is the motor battery: it reaches the motor only through the holder's switch, the board's on/off switch (the power-off switch) and its Motor 1 terminals. Clamp first: the motor is screwed into its mount and the base clamped or taped to the table before the board is switched on. The motor starts only on button A, but a wrong download could start it at once. The spinner is a disc of thin card at most 10 cm across, edges rounded, nothing sharp or loose on it, spinning flat (shaft up) below the top of a card guard wall 2 cm out from it, in a safe zone taped 40 cm across. The safe zone reaches more than 10 cm beyond the guard wall. The board and the holder sit outside it on the adult's side, with motor leads long enough to reach. Fingers, hair, sleeves and cords stay outside the safe zone while the board is on; long hair is tied back. Nobody leans over the zone: watch from outside it, looking down, eyes never level with the disc. Speed limit: the spinner's speed number is never above 50 (of 100). Before each switch-on, the stop drill: someone calls “Stop!” and the adult at the board's switch shows it going off. In a run, on “Stop!” the adult switches off at once; learners never reach into the zone. Rewire only when unpowered: the board and the holder are switched off before any wire, motor, servo or sensor is plugged in, moved or taken out.

    Works towards: Motor speed

  5. Session 5 · 75 min

    Can I describe the power path and show the spinner is safe?

    The prototype, a safe motorised spinner: the learner describes its power path from the battery to the motor and back, says what the signal does, and tests its safe operation with a checklist: clamped, guarded, the speed at most 50, the stop drill works, everyone outside the safe zone, and leads changed only with the power off.

    The adult says first: “Show us your spinner. Tell us the power path. Then test it safely.”

    Learner card

    1. Draw the power path.
    2. Pick a speed up to 50.
    3. Check each rule first.
    4. Call “Stop!” to end the run.
    5. Explain your drawing.

    Key words (show each with a picture): power path · safe · check

    Timing (10 of 75 min at the screen)

    1. 15 minAway from the screen: Draw the power path and the signal on a card, in two colours.
    2. 10 minAt the screen: Choose a speed (20 to 50) and a direction; the simulator, then download.
    3. 15 minAway from the screen: The safety checks, one at a time, each guessed first.
    4. 20 minAway from the screen: Turns at the rig, one pair at a time (about 5 minutes each): A, then “Stop!”; waiting pairs check their drawings.
    5. 15 minAway from the screen: Explain the drawing and the checks to the adult.

    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 learner draws the power path on a card with arrows (battery, holder switch, board and its switch, Motor 1 terminals, motor, and back through the shared ground), and the signal from the micro:bit to the board in another colour. The learner chooses a speed from 20 to 50 and a direction, tries it in the simulator (the display shows the number), and downloads it (the board switched off, the micro:bit out of the board, USB in; USB out once the light on the back stops flashing, the micro:bit back in). Then the safety checks, one at a time, each predicted: the base is clamped; the guard wall and the safe zone are in place; the number is at most 50; everyone is outside the zone; the stop drill works. At the pair's turn at the rig, the adult, with the board switched off, puts the pair's micro:bit in; the stop drill; the adult switches on and presses A; the learner watches the spinner and calls “Stop!”, and the adult switches the board off at once. Last, the learner explains the drawing and the checks to the adult.

    Starting blocks: The learner's own blocks from session 4 (the adult's blocks), with the chosen speed and direction.

    Evidence to collect

    The unit's evidence: the learner describes the power path and tests safe operation: a prediction for each check, a short test table (Check | My guess | What happened | Safe?) for five checks and the run, and the learner's spoken or written description of the power path from the battery through the board to the motor, and of what the signal does.

    Test table columns: Check | My guess | What happened | Safe?

    Predict
    Before each check, the learner says whether it will pass, and why it matters.
    Debug
    If a check fails, the board stays off until it is fixed with the power off; then the whole checklist runs again.
    Reflect
    Which safety check would you teach a younger child first, and why?

    ⚠ Adult checks before power-on: Nothing metal touches the micro:bit, its gold pins or the board, and nothing metal lies under it. Before the adult switches on: the micro:bit is firmly in the board, display facing the Link header, its own battery pack and USB unplugged; both switches were off while anything was plugged in or moved. The board's battery is the motor battery: it reaches the motor only through the holder's switch, the board's on/off switch (the power-off switch) and its Motor 1 terminals. Clamp first: the motor is screwed into its mount and the base clamped or taped to the table before the board is switched on. The motor starts only on button A, but a wrong download could start it at once. The spinner is a disc of thin card at most 10 cm across, edges rounded, nothing sharp or loose on it, spinning flat (shaft up) below the top of a card guard wall 2 cm out from it, in a safe zone taped 40 cm across. The safe zone reaches more than 10 cm beyond the guard wall. The board and the holder sit outside it on the adult's side, with motor leads long enough to reach. Fingers, hair, sleeves and cords stay outside the safe zone while the board is on; long hair is tied back. Nobody leans over the zone: watch from outside it, looking down, eyes never level with the disc. Speed limit: the spinner's speed number is never above 50 (of 100). Before each switch-on, the stop drill: someone calls “Stop!” and the adult at the board's switch shows it going off. In a run, on “Stop!” the adult switches off at once; learners never reach into the zone. Rewire only when unpowered: the board and the holder are switched off before any wire, motor, servo or sensor is plugged in, moved or taken out.

    Works towards: Power vs signal, Motor speed

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
  • Per pair: a Kitronik Compact All-In-One Robotics Board for BBC micro:bit (stock code 5693), its Link header fitted with a 2.54 mm pin header by the adult (soldering is adult-only)
  • Kept by the adult: 4 × AA alkaline cells (1.5 V each, 6 V nominal) in a holder with a screwed-shut cover and its own on/off switch, wired by the adult to the board's power terminal block; no rechargeable cells, Li-ion, LiPo, RC or coin-cell packs
  • Pencils and paper for the test tables
  • One spinner rig per adult, which the pairs take turns at: a Kitronik In-Line Geared TT Hobby Motor (stock code 2547) with leads soldered on by the adult, long enough for the board to sit outside the safe zone, a plastic motor mount, a matching wheel hub, a wooden base and a G-clamp or strong tape
  • Thin card, a cup to draw round, safety scissors, sticky tape and coloured pens for the disc, its mark and the guard wall
  • Masking tape for the safe zone, tape to cap the motor leads, and a stopwatch or a clock with a seconds hand, used by the adult
  • Picture cards: battery, holder switch, board, motor, micro:bit, USB cable

⚠ Safety before any session

  • Batteries: only AA alkaline cells in the board's closed holder, and USB from a computer for downloads; no rechargeable cells, power banks, Li-ion, LiPo, RC packs or coin cells.
  • Cells: the adult fits four new alkaline cells of one type, the right way round, never mixes new and used cells, takes spent cells out and screws the cover shut.
  • The battery holder stays with the adult, beside the board on the adult's side; learners never handle the cells or the holder.
  • The power-off switch is the board's on/off switch: it cuts the battery to the board, the micro:bit and every motor and servo. Anyone may switch it off at any time; only the adult switches it on.
  • The board's battery is the motor battery: it reaches the motor only through the holder's switch, the board's on/off switch (the power-off switch) and its Motor 1 terminals.
  • A motor never runs from a micro:bit pin: it runs only from the board's motor terminals, powered by the board's battery.
  • Clamp first: the motor is screwed into its mount and the base clamped or taped to the table before the board is switched on. The motor starts only on button A, but a wrong download could start it at once.
  • The spinner is a disc of thin card at most 10 cm across, edges rounded, nothing sharp or loose on it, spinning flat (shaft up) below the top of a card guard wall 2 cm out from it, in a safe zone taped 40 cm across.
  • The safe zone reaches more than 10 cm beyond the guard wall. The board and the holder sit outside it on the adult's side, with motor leads long enough to reach.
  • Fingers, hair, sleeves and cords stay outside the safe zone while the board is on; long hair is tied back. Nobody leans over the zone: watch from outside it, looking down, eyes never level with the disc.
  • Before each switch-on, the stop drill: someone calls “Stop!” and the adult at the board's switch shows it going off. In a run, on “Stop!” the adult switches off at once; learners never reach into the zone.
  • Speed limit: the spinner's speed number is never above 50 (of 100).
  • Rewire only when unpowered: the board and the holder are switched off before any wire, motor, servo or sensor is plugged in, moved or taken out.
  • Only the parts the plan names connect to the micro:bit, through the board's Link header. 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.
  • If the board, a motor, the holder or a wire gets warm: switch the board off, don't touch it, tell the adult.
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.
  • Kitronik labels the board Age 11+ and tags it Designed for_Engineers. These plans are adult-led for that reason: the adult builds, wires, powers and switches every rig and keeps the battery holder; the learner changes numbers in blocks, presses the micro:bit's buttons when the adult says, and watches from outside the safe zone or the gate's path.
  • Only one spinner or gate runs at a time near each adult. Its board sits outside the safe zone on the adult's side, with leads long enough to reach, and the adult stands at its switch as the stopper.
  • One powered rig per adult: pairs take turns at it, one pair at a time. Each pair downloads to its own micro:bit, and at the pair's turn the adult, with the board switched off, swaps it into the rig. While they wait, the other pairs predict, fill in their tables or work in the simulator, watching from outside the zone. Each session's timing counts the turns and the waiting.
  • 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.
  • To download, the board is switched off and the adult takes the micro:bit out of it (or the learner does, with the adult watching), holding it by its edges and pulling it straight out; the learner plugs in USB, downloads and unplugs USB once the light on the back stops flashing; the micro:bit goes back in the same way, straight and firmly, display facing the Link header, before the adult switches on. Every swap wears the edge connector a little: swap only to download or at a pair's turn, and never rock the micro:bit out.
  • Before the first session, add the extensions on each computer: in MakeCode's Extensions, search for Kitronik and pick the Kitronik robotics Board; for the distance sensor, search for sonar.
  • The MakeCode simulator prepares the work. Only the real board, 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, not even its motor, servo or distance labs: they wire a 5 V Uno, never a micro:bit.
  • The pack is 6 V nominal (4 × 1.5 V), at the edge of all three ranges: the bottom of Kitronik's recommended 6.0–10.8 V for the board, and the top of the TT motor's 3–6 V and the servo's 4.8–6 V. Expect it to vary: new cells can read above 1.5 V each with nothing running (Energizer's handbook works an example with an open circuit voltage of 1.6 V), and the pack sags under load, because each fresh cell has 150 to 300 milliohms of internal resistance (Energizer E91). Kitronik's board page lists under Requires a Power Supply that links to its 3 × AA holder; these plans use 4 × AA instead, because 3 × AA is 4.5 V nominal, below the board's recommended 6.0 V and the servo's 4.8 V.
  • This unit assumes safe circuits and outputs, not block programming: the adult builds the blocks, and the learner changes only the numbers and the direction, predicts and tests.
  • The adult's blocks start the motor only when button A is pressed and stop it on button B, as Kitronik's guide advises (motors coded off at the start, so they are not running straight away). B is the program's stop; the board's switch is the power-off switch, used on “Stop!” and at the end of every run.
  • The board's battery feeds the motor directly and the micro:bit through the board's 3.3 V regulator; the micro:bit's own battery pack is never plugged in while it sits in the board.
  • Before session 2, the adult solders leads onto the motor (soldering is adult-only), long enough for the board to sit outside the safe zone, builds the spinner rig and checks that the disc cannot touch the guard wall.
  • Readiness decides, not age: a learner who already traces a power path, keeps a motor's speed within a limit and stops it safely can move on to R11-U1.

Planned studio features

Not built yet. The unit runs without them.

  • A micro:bit motor and servo simulator in the studio, with the robotics board's power path drawn and every control labelled as a code setting or a simulated input.
  • Printable picture cards for each session's key words and the power-path cards, and printable learner cards.
  • A printable safety checklist for the spinner, with the columns of its test table.

Sources

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