🛠 DIY Mini Model Guide

Build SmartFlow
for under R 150

A complete cardboard-and-wire miniature model you can build at home using stuff from the kitchen drawer, the stationery shop and a quick trip to Communica.

R 120–150 total materials · Grade 5 friendly

What you need

Cheap Materials List

📦

Cardboard Boxes

Cereal boxes, shoe boxes, tissue boxes — any sturdy cardboard for the base, housing and pole.

Repurpose what's at home

✅ Free — kitchen recycling

🧻

Cardboard Tubes

Toilet paper rolls and paper towel tubes make perfect traffic light poles and wind turbine towers.

Save 2–3 rolls

✅ Free — bathroom cabinet

📰

Old Newspaper / Magazines

Roll tightly for extra structural poles. Scrunch for turbine blade padding.

Any old paper works

✅ Free — recycle pile

🖊️

Markers & Koki Pens

Red, amber/orange, green, black and yellow for colouring all components accurately.

Pack of 6 basics

🏪 Stationery shop / PnP

🎨

Poster Paint or Tempera

Black for the traffic light housing, grey for the base road, yellow for road markings.

Small pots · 4 colours

🏪 Stationery shop

🔵

Coloured Cellophane / Acetate

Cut circles for the traffic light lenses — red, orange/amber and green. Stationery shops sell small sheets.

3 colours · A5 sheet each

🏪 Stationery / Checkers

💡

3× LED Pack (Red+Amber+Green)

Optional but amazing: real LEDs make the lights actually glow. 5mm · comes in mixed packs of 30.

5mm diffused LEDs

🔌 Communica / Takealot

🔋

4× AA Battery Holder + Batteries

Powers the LEDs at 6V. Simple and safe. No soldering needed with a holder and crocodile clips.

6V · on/off switch

🔌 Communica / Game Stores

🐊

Crocodile Clip Wire Set

Connect LED legs to battery holder without soldering. Colour-coded for easy wiring.

10 clips · mixed colours

🔌 Communica / Mantech

🌀

Plastic Bottle Caps (5×)

Milk bottle caps become wind turbine blades. Cut, angle slightly and attach to a cork centre.

Collect from the fridge!

✅ Free — recycling bin

🍶

Cork / Foam Block

Wine cork or craft foam — hub of the wind turbine. Push blade sticks into it at angles.

1 cork or foam cube

🏪 Craft shop / Woolworths

🪡

Craft Sticks / Lolly Sticks

Structural supports, solar panel frame, turbine blade arms, road barriers. Incredibly versatile.

Pack of 50

🏪 Craft/stationery shop

📎

Foil / Aluminium Wrap

Kitchen foil cut into rectangles represents the solar panel cells perfectly. Looks very realistic.

30cm strip of kitchen foil

✅ Free — kitchen drawer

🟦

Blue Sticky Tack / Prestik

Holds everything together temporarily during building. Also positions sensors and components.

1 pack

🏪 Any stationery store

🔫

Hot Glue Gun + 3 Sticks

Strong permanent joins. Adult supervision needed. Bonds cardboard, cork, wood sticks and foil.

Low-temp mini gun preferred

🏪 Craft shop / Builders

✂️

Scissors + Craft Knife

Scissors for cardboard, craft knife for clean slots and holes. Adult supervision for craft knife.

Standard school scissors

✅ Already at home

Total cost to build the mini model

R 120 – R 150

Most items are free recycled materials.
Only LEDs, clips and glue need buying.

What it looks like

The Finished Mini Model

SmartFlow — top-down view of completed model

How to build it

Step-by-Step Build Instructions

🗺️ Make the Base Board

Cut a large piece of cardboard (about 50×50cm — a flattened cereal box works fine). This is your intersection. Paint or draw it to look like roads and grass.

✓

Do: Use a ruler and pencil to draw the roads first, then paint grey inside the lines.

📝

Tip: Paint the grass areas green first and let dry, then paint the roads dark grey over the top.

✓

Road lines: Use white chalk or correction fluid to draw dashed centre lines.

📦 Flat cardboard (50×50cm) 🎨 Grey + green paint 🖊️ White koki / chalk

🚦 Build the Traffic Light Poles

Make 2 traffic lights using toilet paper tubes as poles and small matchbox-sized cardboard pieces as the light housings. Paint them black.

✓

Housing: Cut a 5×3cm strip of thick cardboard. Fold into a rectangular tube and glue. Paint black.

✓

Holes: Use a hole punch or pencil point to make 3 circles vertically. Glue coloured cellophane behind each hole.

💡

With LEDs: Push one LED through each hole from behind. No need for cellophane — the LED colour shows through.

⚠️

Adult help: Ask an adult to help with the craft knife when making holes.

🧻 Toilet roll × 2 📦 Small cardboard strips 🎨 Black paint 🔵 Cellophane circles × 6 💡 Optional: 6× LEDs

🌀 Build the Wind Turbine

Use a paper towel tube as the tower. Push 5 angled plastic bottle caps into a wine cork hub to make the spinning blades. Mount on the base board.

✓

Blades: Push a pencil tip into the cork to make 5 holes evenly spaced around it. Push craft sticks into holes, then hot-glue a bottle cap to each stick at an angle.

💡

Angle matters: Tilt the blade about 20° so it looks like it would catch wind. Blow on it — it should spin!

✓

Tower: Hot-glue the paper towel tube upright to the base board, then push the cork hub onto the top.

✓

Colour: Paint the blades light blue or teal. Write "WIND TURBINE" on a small label and glue to the tower.

🧻 Paper towel tube 🍶 Wine cork 🌀 5× bottle caps 🪡 Craft sticks × 5 🔫 Hot glue

☀️ Make the Solar Panel

Cut a 10×7cm rectangle of thick cardboard. Cover with kitchen foil squares (the cells). Add a craft stick frame and mount at an angle like a real solar panel tilted towards the sun.

✓

Cells: Cut 12 equal squares of kitchen foil. Glue them in a 4×3 grid on the cardboard. Use a koki to draw thin black lines between cells.

✓

Frame: Glue craft sticks around all 4 edges as the frame border.

💡

Mount: Hot-glue a short craft stick as the support strut underneath, angled at 30°. Glue the base of the strut to the cardboard base.

📦 Thick cardboard (10×7cm) 📎 Kitchen foil squares 🪡 Craft sticks (frame) 🔫 Hot glue 🖊️ Black koki (grid lines)

🔋 Make the Battery Box & Controller

A small matchbox is perfect for both the battery and the controller box. Label them clearly and connect with coloured yarn or wire to show the energy flow.

✓

Battery box: Take a matchbox drawer. Paint green. Write "BATTERY 12V" on a small paper label and glue on. Add two small dots of red and black koki for terminals.

✓

Arduino: Same sized box, paint purple/dark. Write "ARDUINO CONTROLLER" on it. Poke small holes in the sides for "wire ports".

✓

Sensors: Cut 4 small 2×1cm cardboard squares. Label them: SENSOR A, B, C, D with road direction. Glue near each road entry.

🧲 2× matchboxes 📦 4× small cardboard squares 🎨 Green + purple paint 🖊️ Marker pen

🔌 Add Wires & Connect Everything

Use coloured wool/yarn or twist ties to show how energy flows through the system. Each colour represents a different type of connection — just like a real circuit diagram.

🎨 Colour Code for Model Wires

Orange/Yellow yarn — Solar panel → MPPT controller

Light blue yarn — Wind turbine → MPPT controller

Green yarn — MPPT controller → Battery

Green yarn — Battery → Arduino controller

Purple yarn — Arduino → Traffic lights (control)

Blue yarn — Sensors → Arduino (data feed)

Red yarn — Battery → Traffic lights (power)

✓

Route wires: Hot-glue small loops of yarn along the base to show the wire paths. Keep them neat and cable-tied.

💡

Real LEDs option: If using LEDs + battery holder, run actual wire from the battery holder through the Arduino matchbox and out to each LED. Twist wires together and tape with coloured tape.

✓

Labels: Cut tiny paper flags and tape to each wire with the name of what it connects.

🪡 Coloured wool/yarn 🐊 Crocodile clip wires 🔋 4×AA battery holder 💡 6× LEDs 🟦 Prestik to route cables

🏷️ Label Everything & Add Finishing Touches

A great model is also a great display. Add neat labels, a title card, a legend and little cardboard cars to bring the intersection to life!

✓

Title card: Cut a 10×5cm card. Write "SmartFlow — Solar & Wind Adaptive Traffic Light" in large letters. Add your name, grade and school. Glue to one corner of the base.

✓

Numbered labels: Cut 6 small numbered circles (1–6). Place them on each component with a matching key on the side explaining what each one is.

✓

Mini cars: Fold small rectangles of cardboard into tiny car shapes. Place 3 on one road and 1 on the other to show the scenario where SmartFlow decides who gets the longer green light.

💡

Sun: Cut a yellow circle and stick it to a craft stick sticking up at the corner — "showing where the solar power comes from."

✓

Legend box: Glue a small piece of cardboard in one corner. Write the wire colour meanings as a legend.

📦 Small label cards 🖊️ Markers (neat writing) 🚗 Folded cardboard cars ⭐ Yellow circle (sun)

🎮

SmartFlow Game

Interactive diagram + quiz + simulator

📋

Full Specs & Real BOM

Architecture · Buy list · Wiring guide