A box that sends voice messages to our family. No screen!
Chief Engineer:
Assistant (Abba):
Build started:
2 builders
2 phases
0 screens
∞ messages
Message Box · Assembly Guide
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A. The Plan
Read this page first. It shows what we are making.
This is a two-person build. One kid + one grown-up. Electricity and downloads are grown-up jobs.
The Message Box lives in your room. Hold the green button and talk — your voice flies to the family
WhatsApp group in Israel. When family answers, the little light turns on. Press play to hear them.
Your voice travels 4,000 km in about one second.
B. Two Phases
Phase 1 — Make it workOne green button. It always sends to the family group. The light and play button bring messages back. This is the whole machine, working.
Phase 2 — Magic tilesA tile for each person, with their photo. Put Savta's tile on the box — now the button sends only to Savta. Like a key for each person.
Message Box · The Plan
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C. Parts
Check the boxes as you find each part. Like a LEGO inventory page.
×1
Raspberry Pi Zero 2
The brain. A tiny computer, smaller than a chocolate bar.
×1
USB speaker
The mouth. Plays the messages.
×1
USB microphone
The ear. Hears your voice.
×1
Powered USB hub
A power strip for USB. The Pi has only one plug — this gives it three.
×1
Micro-SD card
The memory. Holds everything the brain knows.
×2
Big buttons
Green = talk. Yellow = play. The only controls!
×1
Mail light (LED)
Glows when a message is waiting for you.
×1
Power supply
Food for the brain. Stays plugged in.
×1
A box
The body. Wood or strong cardboard. We decorate it at the end.
Also needed: Abba's laptop, a phone with WhatsApp, jumper wires, and a NEW phone number just for the box.
Message Box · Parts
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D. Engineer Words
Real engineers use these words. Now you do too.
ComputerA machine that follows instructions very, very fast. Our Pi follows millions per second.
ProgramA list of instructions we write for the computer. Ours says: "when the green button is held, record."
GPIO pinsThe little metal legs on the Pi. We connect buttons and the light to them. The brain feels the button through the pin.
Wi-FiInvisible radio waves that carry our messages to the internet. No wires!
Voice noteA recording of your voice sent as a message. That's what our box makes.
FlashCopying the brain's starting knowledge onto the SD card. Like installing its imagination.
TestTrying one thing to see if it works, BEFORE building the next thing. Engineers always test.
BugWhen the machine does something we didn't want. Finding bugs is detective work — and it's fun.
Phase 1 — Make it work
Eight steps. Take your time. Test after every step. When Phase 1 is done, you can talk to Israel from your room.
Rule of the workshop: we finish a step, we test it, we high-five. Then the next step.
Message Box · Words + Rules
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Phase 1 · Steps 1–3
Waking up the brain.
1
Give the brain its memory
Put the SD card in the laptop. Use the Raspberry Pi program to copy the brain's software onto it. This is called flashing.
Then push the card into the Pi. Click!
Why? A brand-new computer knows nothing. The SD card is everything it will ever know.
Test: the little green light on the Pi blinks when we plug in power.
2
Connect to Wi-Fi
Abba types the Wi-Fi name and password into the setup. The Pi joins our home internet — with no screen and no keyboard of its own.
Why? Messages travel over the internet. No Wi-Fi = no mail.
Test: the laptop can "call" the Pi over Wi-Fi (Abba types one command and the Pi answers).
3
Plug in the ear and the mouth
Plug the hub into the Pi. Plug the microphone and the speaker into the hub.
Record yourself for 5 seconds. Play it back. Hear your own voice!
Why the hub? The Pi has one USB door. The hub turns one door into three.
Test: you recorded your voice AND heard it back from the speaker.
Message Box · Phase 1
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Phase 1 · Steps 4–5
The box joins WhatsApp.
4
The box gets its own phone number
The box joins WhatsApp like a new family member. We give it a brand-new number, then show it a square code (a QR code) from the phone.
Now WhatsApp thinks our box is a phone. It kind of is!
Why its own number? So ONLY messages sent to the box arrive in your room. Family group chat stays on the grown-ups' phones.
Test: Abba sends "hello" from the laptop through the box's number — and it arrives on his phone.
5
First voice note across the world
We record a hello, the computer squeezes it into WhatsApp's favorite shape, and we send it to our test group.
Watch Abba's phone. A real voice note appears — with the little waveform and everything.
Engineer secret: WhatsApp only shows the nice voice bubble if the sound file is EXACTLY the right kind. Ours is.
Test: play the voice note on the phone. That's your voice, sent by your machine.
Message Box · Phase 1
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Phase 1 · Steps 6–7
Buttons, light, and the rules.
6
Wire the buttons and the light
Connect the green button, the yellow button, and the mail light to the Pi's metal legs (the GPIO pins) with jumper wires.
Each wire goes to its own numbered pin. We follow the map below. Slow and careful.
Why pins? When you press the button, electricity touches the pin. The brain feels it and knows: "record now!"
Test: a tiny practice program — press the button, the light blinks. It's alive!
7
Write the rules
Now Abba and Claude write the real program. It has four rules:
Rule 1: Green button held → record. Rule 2: Green button released → send to the family group. Rule 3: New message from family → mail light ON. Rule 4: Yellow button → play messages, oldest first. Then light OFF.
Why oldest first? Like reading a story — you start at the beginning.
Test: the whole loop. You record, Savta's phone rings with your voice, she answers, the light glows, you press play.
Message Box · Phase 1
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Phase 1 · Step 8 + Final Tests
Making it a real machine.
8
Put it all in the box
Cut holes for the speaker, the buttons, and the light. Mount everything inside. Close it up.
Decorate it. It's yours. Stickers allowed. Encouraged, actually.
Why last? Engineers only close the box when everything inside already works. Opening it again is annoying.
Test: everything still works with the lid closed.
E. Secret Agent Tests
A machine is only done when it survives the tests. Check each box.
The Stranger TestA number the box doesn't know sends it a message. The box must ignore it. No light. Nothing.
The Photo TestFamily sends a photo. The box only does voices — it must skip the photo quietly.
The Blackout TestPull the plug. Plug it back in. The box wakes up by itself and still remembers your unheard messages.
The Three-Message TestThree messages arrive. Press play: they play in order, each one saying who sent it.
The One-Week MissionThe box lives in your room for 7 days. Nobody fixes it, touches the code, or restarts it. If it survives — Phase 1 is COMPLETE.