Build a growbox

A foam box with a camera in the lid. A Raspberry Pi Zero 2 W takes a photo of the plant every few minutes, the coloured lights help it grow, and three sensors measure the temperature, the humidity and the light. Students build it on breadboards. The only soldering is the pins on two sensors, which a teacher does once.

Drag to turn · scroll to zoom

Pull apart

Tap a part to pick it out in the 3D model. Everything else fades back.

How it works

Everything electrical lives on the lid. The door at the front lifts out, so students can get to the plants without touching the wiring.

On the lid

The Pi Zero 2 W and the big breadboard. A T-shaped Raspberry Pi breakout board (often called a T-Cobbler) brings all 40 Pi pins onto the breadboard. The camera points down through a square hole in the middle.

Under the lid

A sturdy printed rack hangs on four posts and holds a strip of 20 RGB LEDs about 50 mm above the plant, angled 20° in towards it, so they grow it well at gentle power. The rack also guides the sensor ribbon and the heater cable, so nothing tangles. They shine red and blue (purple light), which is the light plants use most. We never use white: it draws the most current.

Inside the box

The plant tray on the floor. A small breadboard of sensors on the back wall, with the two light sensors sticking out facing up. A 60 °C heater on the left wall by the door, well away from the sensors. One 10-wire ribbon joins the sensors to the lid.

The foam pieces

One growbox is seven pieces of 20 mm foam. Your teacher cuts them out. Tabs on the walls push into slots in the floor and the lid, so there's no glue. All sizes are in millimetres.

Printed parts

PLA, 0.2 mm layers, 15% infill, no supports. Print the camera sleeve first: test it in the lid hole before you print the rest.

Part	What it does	Print time	Download
Light rack	A 12 mm ring on four 10 mm posts. The LED strip sticks on its underside, which slopes 20° so the lights point at the dish. Built in: a short guide for the rainbow ribbon, and two pairs of small wire loops, one for the LED lead and one for the heater cable. Four pegs push up into the lid.	~2 h 30 m	.stl
Camera sleeve	Pushes up into the lid's square hole from below and holds the camera, lens down.	~20 m	.stl
Plant tray	Holds a 90 mm petri dish in the same place every time, so photos line up. Catches spills. Slides out through the door.	~1 h 40 m	.stl
Heater cradle	Pegs into the left wall, near the door. The heater slides in from the top and sits 8 mm off the foam.	~35 m	.stl
Door handle	Two pegs push into the door face.	~25 m	.stl

Build it

Ten steps over about three lessons, then plan your experiment. Steps 1–3 can happen while the parts print.

Cut the box
Cut the seven foam pieces and the plywood deck from the DXF files. Sand any rough edges lightly with fine sandpaper.
Teacher, or students with supervision · 20 min per box
Push the walls into the floor
- Stand the left and right walls in the floor's side slots. The long edge goes front to back.
- Drop the back wall in between them, into the two back slots.
- Press down until the tabs are flush with the bottom of the floor.
No glue. The walls only stay square once the lid is on, so don't worry if they wobble now.
Make the door
Glue the door plug (120 × 120) to the middle of the door face (160 × 120) with PVA, with the bottom edges level. Push the printed handle's pegs into the face. Let the glue dry overnight.
Foam-safe glue only. PVA or low-temperature hot glue. Spray glue and superglue melt polystyrene.
Glue the deck to the lid
Line up the holes in the plywood deck with the holes in the foam lid and glue them together with PVA. The engraved rectangles show where the breadboard and the Pi go.
Fit the lights and the camera
- Push the camera sleeve up into the lid's square hole from underneath. Drop the camera in from the top, lens down, with its flat cable coming up out of the sleeve. You'll plug that cable into the Pi in the next step.
- Cut a 20-LED length from the RGB LED strip (cut only across the copper pads). Keep the end with the plug.
- Stick the strip round the sloping underside of the light rack, 5 LEDs to a side, starting at the front-right corner. Fold it at each corner: fold back over itself, then fold again at 45°.
- Thread the strip's lead up through the two loops on the front-right post. On the lid it comes out of its hole just behind the LED terminal (J1).
- Push the rack up under the lid so its four pegs go into the peg holes.
Mount the Pi and the breadboard
Screw the Pi Zero 2 W onto the deck's back-left corner with nylon standoffs, ports facing the back. Before you peel anything, turn the big breadboard the right way round: column 1 at the left end (by the Pi's corner) and row a along the front, nearest the door, with row j at the back. Facing the door, the numbers 1, 5, 10… should read left to right along the board. Stuck on backwards, every hole in the wiring steps is in the wrong place, so check with a partner first. Then peel the backing off and stick it on its rectangle. Plug the T-shaped Pi breakout board in at the left end. Join it to the Pi with the 40-wire ribbon: run it straight forward from the Pi, fold it once at 45° over the breakout board, and push it down into the socket. The stripe on the ribbon is pin 1.
Then plug in the camera: gently lift the little black latch on the Pi Zero's camera socket (the narrow one at the right-hand end), slide the camera's flat cable in with its shiny contacts facing the board, and press the latch back down.
Wire the big breadboard
Work through the Breadboard assembly page. Its steps 1–12 wire this big breadboard; steps 13–17 build the sensor board in the next step. Each one adds a few pieces, explains why they're there, and shows exactly where they go in 3D.
Never join the Pi's 5 V pins to the breadboard. The breadboard power module powers the lights and the heater. The Pi has its own supply. Only the grounds (black) are joined.
Build the sensor board
- Teacher: solder right-angle pins onto the BH1750 and the TCS34725, so they stick out of the board facing up. The 3D reference below shows what they should look like: the long ends of the pins point straight out from the edge, level with the board.
- The DHT11 (temperature and humidity) comes with its straight pins already fitted, so it needs no soldering. It plugs into row f and hangs down over the middle gap.
- Wire the small breadboard: Breadboard assembly, steps 13–17.
- Stick it on the inside of the back wall, centred, with its bottom edge 2 mm above the floor. Seen from the door: column 1 on the left, row a at the bottom (where the sensors are) and row j at the top, nearest the lid.
- Push the heater into its cradle and the cradle's pegs into the left wall, near the door, below the rack's heater loops.
Reference · drag to turn
Join the lid to the box
- If the ribbon's top end is still plugged into the big breadboard from the assembly steps, unplug it. Feed the 10-wire ribbon up through the rack's short guide and the lid's slot, and thread the heater wires up through the two loops on the rack's front-left post and out of the lid's heater hole.
- Lower the lid so the six wall tabs go into its slots. Press it down evenly.
- Plug the ribbon back into the big breadboard: row c, columns 25–34, brown wire in column 25.
- Screw the heater's two wires into J2 (row h, columns 31–32). It doesn't mind which way round. Tighten the screws and give each wire a gentle tug.
Reference · drag to turn
Check, then power up
- A partner checks every wire against the Breadboard assembly steps before anything is plugged in.
- Power module: the back jumper is on 5 V, and nothing is plugged into the front red + rail.
- Plug in the Pi's supply first, then the breadboard supply.
- Slide the tray in with your plants in their petri dish. Push the door in.
Software comes later. The Pi will run a small web page on the school network. This build book covers the hardware only.
Plan your experiment
With your class, plan a controlled experiment on the Experimental design page: choose the one variable to change across the four growboxes, and which growbox is yours. Then set your growbox in Your settings.

Safety rules for the class

Unplug before you change a wire. Both supplies, every time.

The heater gets to 60 °C. That's hot enough to sting. Touch only its wires. It sits in its cradle so it never touches the foam.

Don't look straight into the LEDs at full brightness. The software will keep them at about half.

Water stays in the tray. Fill the petri dish outside the box and carry the tray in level.

Breadboard assembly, step by step

Build both breadboards one step at a time. Each step shows the pieces you need, what they're for, and exactly where they go. Turn the 3D board to see each wire. New pieces drop in, then the circuit lights up to show where the electricity flows.

What you'll learn, in order

Each step adds one big idea. Click a step to jump to it, or use the arrow keys.

Drag to turn · scroll to zoom

Experimental design

Plan your class's controlled experiment, then set your growbox.

Under development

The planning activities for this page are still being written. For now, make your class plan here, then go to Your settings.

Your class plan

Your class changes one variable: each growbox gets a different value of it. Everything else stays the same in every growbox: those are the controlled variables.

How many growboxes is your class running?

What will your class change?

Controlled variables: the same in every growbox

Which growbox is your group's?

Your settings

Your growbox's day: the settings it will keep for your experiment. Check them, then copy them to apply to your growbox when it's connected.

Your growbox's day

Plan one day. Your growbox repeats it every day of your experiment. Change only your class's variable; the rest are controlled variables, the same as the other groups.

TemperatureThe heater warms the box to this, all day and all night. It can't cool the box below the room.

25 °C

20 °C30 °C40 °C

Day lengthHow many hours of light your plants get in every 24 hours. The rest of the day is dark.

16 hours

midnight6 ammidday6 pmmidnight

When the lights come onYour day length starts at this time each day. The strip above shows it.

Lights come on at

BrightnessHow bright the lights shine on your plants, in lux. A classroom is about 400 lux; a sunny windowsill can be over 1000.

600 lux

0 (off)7501500 lux

Light colourThe LEDs only make red, green and blue light. Mixing them makes every other colour. Plants use red and blue light most, and bounce green light away: that's why leaves look green.

Or mix your own:

Red100%

Green0%

Blue100%

Your light: Purple

Back to the class plan

For teachers

Everything a teacher needs to run the student growbox with a Year 7–8 class. Start with the risk assessment and the costs, so you can get approval and order the parts. Then work through the five jobs in Before class (cutting, soldering, setting up the microSD cards and checking the Wi-Fi) before your students start building.

Risk assessment

For a Year 7–8 class building and running the student growbox. Check it against your school's own policies and templates, and add anything particular to your room.

Activity: building and running a student growboxStudents: Year 7–8, in groupsSupervision: classroom teacherLow Medium High rating from likelihood × consequence

Hazard	What could happen	Before	Controls	After
Soldering ironTeacher only, before class	Burns from the 350 °C tip; a dropped iron starting a fire.	Medium	Teacher solders, away from students Iron always back in its stand, on a heat-proof mat Switched off and unplugged when finished	Low
Solder fumesTeacher only	Breathing in flux fumes.	Medium	Lead-free solder Fume extractor or a well-ventilated room Wash hands afterwards	Low
Cutting the foam and the plyTeacher or technician	Fumes from hot-wire or laser cutting; cuts.	Medium	Done before class, on the school's CNC or laser cutter Machine's own extraction and procedures Students receive finished pieces	Low
Hand toolsStudents	Cuts or pinches from side cutters and wire strippers; flying wire offcuts.	Medium	Demonstrate first Cut away from the body and point offcuts down Safety glasses when trimming wire	Low
Electrical: wiring mistakesStudents	A short circuit makes a part or wire hot.	Medium	Power unplugged while wiring Teacher checks the board before the first switch-on Warm part or burning smell: unplug and tell the teacher	Low
Electrical: mainsEveryone	Shock from a damaged charger or lead.	Medium	The growbox runs on 5 V; mains only reaches the charger plug Approved chargers, tested and tagged under school policy Check leads before use; no power boards near water	Low
HeaterStudents	Touching the heater while it's on.	Low	The PTC heater limits itself to 60 °C Held in its cradle, away from the door Unplug before reaching inside	Low
Water near electronicsStudents	Spills reaching the boards or the charger.	Medium	Fill the plant tray outside the box The breadboards and Pi sit on the lid, above the water Unplug before moving the box; wipe up spills	Low
Plants and pond waterStudents	Germs from pond water or duckweed.	Low	Plants from a supplier, not a wild pond Wash hands after handling	Low
Bright lightsStudents	Eye discomfort from looking into the LEDs.	Low	Don't look straight into the lights Door closed while it's running	Low
CablesEveryone	Tripping over power leads.	Low	Growboxes against a wall, near the power point Leads kept off the floor and walkways	Low
Wi-Fi passwordSchool network	The network password shared further than it should be.	Low	The teacher types it into Device connection It goes to the growbox over Bluetooth and isn't saved on this page	Low

Costs and parts

Prices in Australian dollars including GST, checked on 4 October 2026. The Pi and the camera are Core Electronics prices. The rest are typical Australian retail prices. Check before you order.

—One kit, bought on its own

—Class set of four kits

—Each kit in a class set

—Saved per kit by buying four

Already got some of it? Tick anything your school already has (USB chargers, resistors, glue, PLA) and the totals update. A class set is cheaper per kit because one LED strip, one ribbon and one foam sheet are shared between kits.

Have	Item	What it's for	Buy from	Each	1 kit	Class set (4)

Tools you'll need (not in the price)

A 3D printer, a way to cut foam (CNC hot wire, CNC router or laser), a laser cutter for the ply deck, a small Phillips screwdriver for the screw terminals, side cutters and a wire stripper.

Ways to spend less

The camera is the most expensive part. A generic 5 MP OV5647 camera for the Pi Zero costs about A$15 (it saves A$33), but you have to twist the lens by hand to focus at 11 cm. AliExpress prices for the sensors, cobbler and power module are about half, with two to four weeks of shipping.

Before class

Cut the foam

Teacher or technician · on a CNC hot-wire cutter, CNC router or laser cutter

Two boxes fit on one 1200 × 600 × 20 mm sheet of expanded polystyrene (EPS). All sizes are in millimetres. Slots are cut the same size as the tabs: foam squashes, so they push in tight.

Sheet, two boxes (.dxf) One box (.dxf)

Safety. Laser cutting polystyrene melts it, gives off styrene fumes and can catch fire. Many schools don't allow it. A CNC hot-wire cutter or a CNC router with a sharp bit is safer. If you do laser cut, use full extraction, low power and many passes, and never leave the laser.

Teacher tip. Cut one test tab and slot first. If the tab is loose, make the slots 0.5 mm smaller in your CAM program. If it's too tight to push in, make them 0.5 mm bigger. The DXF uses one layer called CUT for every cut line.
Laser-cut the lid deck

Teacher or technician · laser cutter · about 10 minutes a deck

A 200 × 200 mm square of 3 mm plywood, glued on top of the foam lid. The Pi and the big breadboard sit on it, and the laser engraves the made-this, FarLabs and Plants for Space marks on its open corner.
- Red lines: cut right through. The camera hole, the LED and heater lead holes, the ribbon slot, the four Pi screw holes and the outside edge.
- Blue lines: a light line engrave, marking where the breadboard and the Pi go.
- Black shapes: fill-engrave. The three marks.
Lid deck with engraving (.svg) Lid deck with engraving (.dxf) Plain lid deck (.dxf)

Teacher tip. In the DXF, set the ENGRAVE layer to fill-engrave and the CUT layer to cut. Engrave first, then cut, so the deck doesn't move. Glue it to the lid with PVA, lined up with the camera hole.
Solder the light sensors' pins

Teacher · about 15 minutes a kit · 12 joints

Two of the three sensors come without pins. Solder right-angle pins onto them once, and students can push them into the breadboard like everything else. Students don't solder in this build.

BH1750 light sensor (GY-302) + 5 pinsTCS34725 colour sensor + 7 pinsRight-angle header strip, 40 pinsDHT11: pins already fitted

Back: as they come · Front: soldered · drag to turn
1. Snap a 5-pin and a 7-pin piece off the header strip.
2. Push the short ends down through the holes from the top of the board, the side with the chip. The long ends point straight out past the edge, level with the board. A blob of Blu Tack holds them while you turn it over.
3. Solder one end pin, check the strip is square, then solder the rest. A good joint is a small shiny cone with no solder bridging to the next pin.
4. Plug both into a spare breadboard to check they fit.
Use lead-free solder, a fume extractor or an open window, and the iron's stand. Wash your hands afterwards.
Put growbox OS on the microSD card

Teacher · about 10 minutes a card · once per kit

growbox OS is the software for the Pi: it runs the lights, the heater, the sensors and the camera, and serves the growbox dashboard.

Download growbox OSComing soon
1. Install Raspberry Pi Imager on a computer (Windows, Mac or Linux).
2. Put the 32 GB microSD card into the computer, using an SD adapter or a USB card reader.
3. In Imager, choose Raspberry Pi Zero 2 W as the device.
4. For the operating system, scroll down to Use custom and pick the growbox OS file you downloaded. You don't need to unzip it.
5. For storage, pick the microSD card. Check the size is right: everything on the card is erased.
6. When Imager asks about OS customisation, choose No. The growbox gets its Wi-Fi from Device connection on this page.
7. Wait for it to write and verify, then eject the card. Label the card and its Pi with the same number (Growbox 1, 2, 3, 4).
8. Push the card into the Pi Zero, label side out. The first start takes about a minute.
Check the Wi-Fi

Teacher, with your school's IT team · do this a week before

Students connect each growbox to Wi-Fi from Device connection, then open its dashboard from a laptop or tablet. That only works if the network does all four of these:

It MUST have 2.4 GHz
The Pi Zero 2 W only has 2.4 GHz Wi-Fi. It can't see a 5 GHz-only network at all. A network that offers both bands under one name is fine, as long as 2.4 GHz is switched on.

Devices MUST be able to reach each other
The dashboard comes straight from the growbox, so a student's laptop has to be able to reach it on the network. Networks with "client isolation" or "AP isolation", which most guest networks have, block this.

A name and a password
WPA2-Personal: one shared password. Networks where everyone logs in with their own username (WPA2-Enterprise) or a sign-in web page won't work.

Everyone on the same network
The growboxes and the students' laptops or tablets have to be on the same Wi-Fi network.

What to ask IT: "We have four Raspberry Pi Zero 2 W devices for a science project. Can we have a WPA2-Personal network with 2.4 GHz on, where student devices can reach the Pis directly (no client isolation) on port 7979?" If the school network can't, a small travel router in the classroom works: connect the growboxes and the students' devices to it.

The Connect button uses Bluetooth, which works in Chrome or Edge on a laptop, Chromebook or Android tablet. iPads can't do the Bluetooth step, but they can open a growbox's dashboard once someone else has connected it. Type the Wi-Fi password yourself rather than giving it to students.

Extra information

Power

Power budget. The breadboard power module gets 5 V from a 3 A USB-C supply. The 20-LED strip on two colours at full uses about 0.8 A, and the heater up to 1 A when cold. Breadboard contacts are good for about 1 A each, so the software will run the LEDs at about half and pulse the heater. If the first LED flickers, the fix is a 74AHCT125 chip (about A$2) between GPIO 18 and R1 to lift the signal to 5 V. Most builds never need it.

Chip design: check your wiring

Finished the breadboard assembly? Check your work here before you plug anything in. Compare your two boards with these diagrams, one wire at a time.

Check the big breadboard, on the lid

Hover over a wire to light it up, then find the same wire on your board. Check both ends: the right row letter and the right column number. Short wires lie flat on the board; tall wires arch over from the Pi breakout board.

Check the sensor breadboard, on the back wall

Check the ribbon is in row h with brown in column 2, the two light sensors are along row a, and the DHT11 is in row f, hanging over the middle gap. Then check every short wire, both ends.

Check it in 3D

Turn this model to match your board, then compare. Switch off the tall wires to check the flat ones underneath, or switch off the parts to see every wire's ends.

Drag to turn · scroll to zoom

Check the Pi's pins

Each job uses one GPIO pin. Check each tall wire starts at the right label on the breakout board.

Job	GPIO

Check your sensors' labels. Different makers put the DHT11, BH1750 and TCS34725 pins in different orders. Match the letters printed on your sensor, not just the positions in the diagram.

All checked? Do the final checks with a partner in Breadboard assembly, step 17, then plug in.

What is a growbox?

A growbox is a small box where you control everything a plant feels: how bright the light is, what colour it is, how many hours a day it's on, and how warm it is. You'll build one, then use it to find out what makes plants grow.

A controlled experiment in a box

Outside, the weather, the season and the shade all change at once, so you can't tell which one made a plant grow. In a controlled experiment you change just one variable and hold the others steady. A growbox lets you do that.

1

The variable you change

The light's colour, how many hours a day it's on, or how warm the box is: one of them, different in each growbox.

2

Controlled variables

The plants, the water, the box, and every setting you aren't testing stay the same in every growbox.

3

What you measure

The camera takes a photo every few minutes, and the sensors record the temperature, the humidity and the light, day and night.

Your class can run four growboxes, each testing something different, and compare what happens.

What the camera sees

Two weeks of duckweed, squeezed into 30 seconds. Each little leaf buds off new ones, so you can count them and see how fast your plants grow.

What you'll do

1

Build

Put the box together and wire up the lights, sensors and camera on breadboards.

Build book → 2

Plan

Choose the one variable your class will change, and which growbox is yours.

Experimental design → 3

Grow

Connect your growbox, set the lights and the heater, and watch your plants on the dashboard.

Device connection →

4

Share

Look at your photos and graphs, compare with the other groups, and tell the class what you found.

What you'll learn

How to build circuits

Use breadboards, wires and resistors to connect lights, a heater and three sensors to a Raspberry Pi, a small computer about the size of a stick of chewing gum.

How to read real data

Turn time-lapse photos and graphs of temperature, humidity and light into evidence about how your plants grew.

The build in 40 seconds

Here's everything you'll build, start to finish. Pause it on any step and drag to turn it around.

Cut the foam

0:00

Walkthrough video (.mp4)

Build a growbox

On the lid

Under the lid

Inside the box

Cut the box

Push the walls into the floor

Make the door

Glue the deck to the lid

Fit the lights and the camera

Mount the Pi and the breadboard

Wire the big breadboard

Build the sensor board

Join the lid to the box

Check, then power up

Plan your experiment

Under development

Your class plan

Risk assessment

Costs and parts

Tools you'll need (not in the price)

Ways to spend less

Before class

Cut the foam

Laser-cut the lid deck

Solder the light sensors' pins

Put growbox OS on the microSD card

Check the Wi-Fi

Extra information

Power

A controlled experiment in a box

The variable you change

Controlled variables

What you measure

What you'll do

Build

Plan

Grow

Share

What you'll learn

How to build circuits

How to read real data