Your phone sits in your pocket doing nothing. Someone taps your name on their screen. Less than two seconds later your phone is ringing. This project shows you what actually happened in those two seconds.

How a call reaches you

A call does not travel straight from one phone to another. It goes up to a tower, through the network, and back down. Here is the full path.

What wakes up inside your phone

Once the paging signal arrives, six parts of your phone take turns. Each one does its job and hands the work to the next. In the simulation you can watch this happen, and each part lights up in its own colour.

Awake or asleep

This is the part most people find surprising. When your screen is off, nearly the whole phone is switched off too.

Part	While idle	Why
Cellular modem / baseband	Low-power monitoring	Monitors cellular signaling for relevant network events.
Antenna	Connected and available	Provides the RF path for receiving and transmitting radio signals.
Application processor (CPU/SoC)	Low-power state	Reduces power consumption when full processing is not required.
Kernel	Not continuously executing	Kernel code executes on the application processor when the operating system needs to handle events or perform system work.
Screen	Off	Display hardware is not actively showing the user interface.
Speaker	Inactive	Activated when audio such as a ringtone needs to be produced.

Why the phone finds you so fast

The network already knows roughly where you are. Your phone quietly checks in with nearby towers as you move around, so the carrier keeps a note of which small group of towers you are near. When a call comes in, it does not have to search the whole country. It only pages the handful of towers in your area, and your phone answers.

What you can do in this simulation

• Watch the wake up in order. Call someone and the camera follows the signal from the caller, up to the tower, back down, and then inside the phone while each chip lights up.
• Look inside a real board. Hardware View fades away the back glass so you can see the logic board, the chips, the battery and the antenna strip, with a label pinned to each one.
• Move the phones. Drag any phone and it will connect to whichever tower is now closest, so you can see how distance changes the path.
• Listen to the whole story. Explain Project plays the simulation on its own and talks you through it in English, Hindi, Telugu or Tamil, with subtitles on screen.
• Run it like a computer. The terminal lets you add contacts, power phones on and off, ping devices, trace routes and start calls between other people.
• Change the conditions. Switch between day and night, and turn on rain to see the scene under bad weather.

Built with

Three.js draws the 3D scene, GSAP runs the animations and camera moves, Tone.js makes the sounds, and the browser's own speech engine reads the narration. The whole thing is one HTML file with no server behind it.

Made by I. Sanjay Raghav Reddy for Druvexaa.

New here? Read the first two sections and you will be able to use everything. The rest is for when you want to go further.

Voice note: English works on most browsers. Edge is recommended for Hindi, Telugu & Tamil; Chrome, Firefox and other browsers may have limited support. Subtitles are always available.

Start here

The quickest way to see what this project does is to make a call.

1. Click Contacts at the bottom of the screen.
2. Pick any name from the list.
3. Now just watch. The camera follows the signal by itself. You do not need to click anything.

You will see the signal leave your phone, go up to the nearest tower, come back down into the other person's phone, and then the phone opens up so you can watch each chip switch on in turn. At the end the phone turns around and rings.

What is on your screen

Moving the camera

• Turn around the scene: hold the left mouse button on empty space and move the mouse.
• Zoom in and out: scroll the mouse wheel. On a phone or tablet, pinch with two fingers.
• Move a phone: click and drag the phone itself. It will link to whichever tower is closest to its new spot.
• Lost? Click Reset View to go back to the wide shot.

The buttons at the bottom

• Contacts: pick someone to call. This is the main thing to try first.
• Hardware View: the back of the phone fades away so you can see the parts inside. Each one gets a name tag with a line pointing to it.
• Front View: puts the back cover on again and shows the screen.
• Reset View: moves the camera back to the starting position.
• Voice Assistant: lets you speak instead of typing. See the next section.
• Terminal: shows the black log window if you closed it.
• Day / Night: switches the lighting.
• Weather: turns rain on and off.
• Instructions: opens this page.
• About: explains how phone calls actually work, with diagrams.
• Guide Tour: replays the short tour you saw at the start.
• Reset: puts everything back to how it was when the page opened. Phones return to their spots, back covers close, screens go blank and the camera pulls out.

Using your voice

Click Voice Assistant, wait for the button to say it is listening, then speak normally. You can say things like:

• call Tarun to start a call
• explain project to run the guided walkthrough
• explain project in telugu to run it in another language
• power off all to switch every phone off
• reset to start again

Voice input needs a microphone, and it works in Chrome and Edge. If your browser does not support it, everything can still be typed into the terminal instead.

The guided walkthrough

Type or say explain project and the simulation plays itself from start to finish. As each part is explained, the camera flies to that chip, dims the others and lights up the one being talked about. You can watch the signal jump from chip to chip in the colour of whichever part is doing the work.

A small bar appears with controls to pause, change speed and switch language. There are four languages to choose from: English, Hindi, Telugu and Tamil.

Reading the colours

Each part of the phone has its own colour, and it is the same colour everywhere: on the chip, on the moving signal and on the name tag.

Colour	Part	What it is doing
Green	Antenna	Receives the radio-frequency signal from the cellular network
Gold	Modem	Processes the received cellular signal
Violet	Telephony	Interprets the signaling and identifies the incoming call
Orange	Kernel	Coordinates hardware, drivers, interrupts and scheduling
Blue	CPU	Runs the phone app and draws the screen
Red	Speaker	Produces the ringtone

Typing commands

Click the box at the bottom of the black log window, type a command and press Enter. Press the up and down arrow keys to go back through what you typed before. Type man to see the full list inside the terminal.

Everyday commands

• call <name>: call someone. e.g. call Tarun
• call <name1> <name2>: call more than one person at once, which makes a conference call.
• text <name> <message>: send a message. e.g. text Charan hello there
• ls contacts: show all the names you can call.
• vi <name>: show one person's details. e.g. vi Charan
• history: list every call made so far.
• clear: wipe the log window.
• reset: start the whole simulation again.

Changing the contact list

• add <name>: add a new person, and a new phone appears in the scene. e.g. add Priya
• edit <name>: change a person's name or number.
• del <name>: remove a person and their phone.
• ll contacts: show how many times you called each person.
• edit password: change the password used for remote commands.

Groups

• group add <groupName> <name1> <name2>: make a group. e.g. group add family Charan Tarun
• group list: show all your groups.
• group show <groupName>: show who is in a group.
• group del <groupName>: delete a group.
• Once a group exists you can use its name anywhere a person's name goes, like call family.

Controlling the phones

• poweron <name|group|all>: switch phones on. e.g. poweron all
• poweroff <name|group|all>: switch phones off. A phone that is off cannot be called, which is worth trying.
• reboot <name|group|all>: restart a phone.
• call <caller> to <callee>: make two other people call each other. This asks for the password first. e.g. call Charan to Akshay

Looking at the network

• scan: find every phone that is switched on.
• ping <name>: check whether you can reach someone's phone.
• route <name>: show the path a call would take to reach them.
• network or status: show what your own hardware is doing right now.
• browse: pretend to load a web page, so you can see data moving.
• broadcast <group|all> <message>: send one message to lots of phones.
• speed <slow|normal|fast>: make the animations run slower or faster.

Things worth trying

• Switch a phone off with poweroff Mahesh, then try calling them. Watch what the log says.
• Drag a phone right across to the far tower, then call it and see the path change.
• Turn on rain, then make a call and look at how the signal behaves.
• Open Hardware View and click on any glowing chip during a call to read what it does.
• Run explain project in tamil and read the subtitles.

If something looks stuck

• Press Reset. It puts every phone, camera and cover back to the start.
• If the back cover of a phone is still see through, Reset or Front View will close it.
• If the narration is silent, look at the log. It will tell you if your device has no voice for that language.
• If nothing responds at all, reload the page. Nothing is saved, so you lose nothing.