A JSS1 BUILD-AND-CODE ADVENTURE

Can we build a house that detects visitors?

A smart house that sees an approaching object, lights up, and sounds an alert.

APPROACH→MEASURE→DECIDE→ALERT

First, meet the finished design. Then we build this exact house together.

Generating concept image…

MISSION SIMULATION

Watch the smart house in action

This is a visual simulation, not a live hardware connection.

DISTANCE100 cm

VISITOR DETECTED!

THE LOGIC LOOP

01APPROACHVisitor moves toward the door.

02MEASUREUltrasonic echo returns a distance.

03DECIDEThe program checks the 50 cm rule.

04ALERTLED stays on; one short beep marks a new approach.

THE BUILD KIT

Meet the components

Every part has one clear job in our smart house.

UNO

Arduino Uno

The brain: it reads the sensor and controls the alert.

HC-SR04 sensor

Sends a sound pulse and measures the returning echo.

LED

A visual alert that glows near the door.

Buzzer

Makes one short sound for each new approach.

Breadboard

A reusable platform for tidy connections.

Jumper wires

Electrical pathways between the parts.

Ω

220–330 Ω resistor

Protects the LED by limiting current.

Cardboard or foam board

The affordable house body and stable base.

PLAN BEFORE YOU CUT

Design the house blueprint

The sensor must face outward and stay clear of the cardboard.

SENSOR
faces outward

LED

ELECTRONICS
access compartment

WALLS

ROOF

FRONT DOOR

STABLE BASE

01Leave a doorway for the visitor.

02Mount the HC-SR04 above or beside the entrance.

03Keep Arduino and wiring accessible, not sealed inside.

BLUEPRINT → BUILD

CONSTRUCTION BAY

Build the cardboard house

Build the same simple, sturdy design shown in the reveal.

01
Measure and mark
Mark walls, a door opening, and a roof on cardboard.
✓
02
Cut the panels
Cut carefully, leaving clean edges for joining.
✓
03
Join the walls
Make a square body and attach the front panel.
✓
04
Attach roof and base
Fix the roof to a stable base; leave the electronics accessible.
✓

!Safety first:use cutting tools carefully and under adult supervision.

WIRING 01 / INPUT

Connect the ultrasonic sensor

One wire at a time. Match every label to the correct Arduino pin.

ARDUINO
UNO5VGNDD9D10

HC-SR04VCCGNDTRIGECHO

Sensor pin map
Sensor pin	Arduino Uno
VCC	5V
GND	GND
TRIG	D9
ECHO	D10

)))

Echo idea
The sensor sends a sound pulse and measures how long the returning echo takes.

WIRING 02 / LIGHT

Connect the LED

The LED sits beside the door so a visitor can see the alert.

LED near door

D13

220–330 Ω

GND

D13 → resistor → LED long leg → LED short leg → GND

The resistor must remain in the circuit to limit current and protect the LED.

WIRING 03 / SOUND

Connect the buzzer

A short beep announces a new approach, not every sensor reading.

+−

Buzzer inside / beside entrance

+Buzzer positive (+)D8

−Buzzer negative (−)GND

One approach = one short beep

The memory variable stops repeated beeps while someone remains close.

PRE-FLIGHT CHECK

Check the complete circuit

Trace the full path before connecting USB power.

UNO

✓Sensor power checked

✓Sensor pins checked

✓LED polarity checked

✓LED resistor present

✓Buzzer polarity checked

✓All grounds connected

POWER OFF WHILE WIRINGDisconnect USB power before changing a connection.

THE SOFTWARE LAB

Enter the PictoBlox lab

Visual blocks first: students build the logic without typing the program.

PictoBlox • Stage Mode

BLOCKS

STAGE MODE

when green flag clicked

forever

read distance

01Open PictoBlox.
02Select Block Coding and Arduino Uno.
03Connect the correct COM port.
04Select Stage Mode.
05Upload the required firmware if prompted.
06Keep Arduino connected while Stage Mode runs.

Interface shown as an illustration. PictoBlox block names can vary by version and extension.

BLOCK TOOLBOX

Find the required PictoBlox blocks

Look for the function, then match the closest supported label in your version.

EVENTS

when green flag clicked

CONTROL

forever

if then

if then else

wait

OPERATORS

< less than

= equals

VARIABLES

create someoneNear

set someoneNear to 0

ARDUINO / EXTENSION

ultrasonic distance in cm

digital pin HIGH / LOW

play tone, if available

THE MEMORY SWITCH

Create the someoneNear variable

This tiny memory switch makes the alert feel intelligent.

someoneNear0

READY FOR A NEW APPROACH

0No current approach has beeped. A new visitor may trigger the buzzer.

1This approach already beeped. Keep LED on, but stay quiet.

0→1→0visitor arrives → visitor stays → visitor leaves

BLOCK PROGRAM / PRIMARY METHOD

Build the PictoBlox program

Arrange the visual logic in this order. These are intended functions; exact labels can vary.

when green flag clicked

set someoneNear to 0

set digital pin 13 output to LOW

forever

read ultrasonic distance: TRIG 9 / ECHO 10

if distance < 50 then

set digital pin 13 output to HIGH

if someoneNear = 0 then

set someoneNear to 1

play tone on pin 8: 1000 Hz / 0.3 s

else

set digital pin 13 output to LOW

set someoneNear to 0

wait 0.1 seconds

UNDER 50 CMLED stays ON.

FIRST DETECTIONOne short beep, then someoneNear becomes 1.

MOVES AWAYLED OFF; reset to 0 for the next approach.

ROBUSTNESS TIPTreat an invalid or missing reading as no detection when your blocks expose that condition.

THINK LIKE A PROGRAMMER

Understand the program logic

Follow the glowing path: the loop never stops checking.

START

↓

READ DISTANCE

↓

Is distance less than 50 cm?

YES

TURN LED ON

↓

Already beeped?

NOBEEP ONCE SET 1

YESSTAY QUIET

NO

LED OFF SET 0

↻ REPEAT FOREVER

MISSION TEST

Upload and test in PictoBlox

The animation shows expected results; it does not read a real Arduino.

SIMULATION MONITOR

> distance = 72 cmLED OFF • SILENT

> distance = 38 cmLED ON • ONE BEEP

> distance = 91 cmLED OFF • RESET

01Confirm the Arduino board.
02Confirm the COM port and firmware.
03Check sensor and actuator connections.
04Start the PictoBlox program.
05Test with a hand or object at different distances.

EXPECTED RESULTSFarther than 50 cm: off and silent. Within 50 cm: LED on and one beep. Move away: off and ready again.

BACKUP WORKFLOW

Blocks missing? No problem.

This Arduino C++ sketch is a backup for a compatible Arduino programming workflow — not PictoBlox visual blocks.

MATCHED PINSTRIG 9, ECHO 10, LED 13, buzzer 8.

DISTANCE MATHpulseIn reads echo time; the formula converts it to centimetres.

MEMORYsomeoneNear prevents repeated beeps while an object stays close.

HOW TO USESwitch to a compatible workflow such as Arduino IDE, upload the sketch, then test.

ENGINEER'S DEBUG BAY

Troubleshooting engineers

Find the symptom, check the simplest cause, and test again.

?

Sensor block missing

Confirm Arduino Uno and the correct extension. Check support in your PictoBlox version; use the backup when needed.

?

Buzzer block missing

Check tone or actuator blocks. Digital HIGH/LOW is not automatically a proper tone.

!

LED stays off

Check polarity, resistor, D13, and GND.

!

Buzzer does not beep

Check polarity, D8, GND, and the selected programming method.

↺

Distance is unreliable

Check TRIG, ECHO, sensor direction, power, and loose connections.

↺

Program will not start

Check board selection, COM port, USB cable, and Stage Mode firmware.

MISSION COMPLETE

You designed it. You built it. You programmed it.

Now explain how your smart house detects an approaching visitor.

APPROACH→MEASURE→DECIDE→ALERT

✓House constructed

✓Sensor installed

✓LED and buzzer connected

✓Blocks arranged and tested

✓Backup code available