Elegoo Smart Robot Car · V4 · Session 2

Build Your Robot Car

Today we turn a box of parts into a real, rolling robot car you built with your own hands.

90 min Beginner Ages 8+

What we'll do today 🛠️

Last session you met your car and drove it. This session you build one! Don't worry — you won't have to remember anything. Your kit comes with a printed manual and there's an official video that show every single screw. The manual is your turn-by-turn map; this page is the big picture: it splits the build into a few friendly milestones, shows you what each finished chunk should look like, and points out the few tricky spots where you'll want to slow down.

Here's where we're headed — a fully built car, ready to roll:

The finished ELEGOO Smart Robot Car V4 — the reveal from the official ELEGOO assembly video (≈7:28).
How to use this page: keep your paper manual (or the video) open beside you for the exact screws. When you reach a new chunk, read our milestone here first so you know what you're aiming for — then follow the manual step by step. Tick off each milestone as you finish it!
Tiny screws ahead! Some screws are only 1.6 mm — smaller than a grain of rice. Always use the little screwdriver from the kit, work over a tray or plate so nothing rolls away, and ask an adult to help with the fiddly ones. Never force a screw; if it won't turn, back it out and try again straight.

What you need

Tip your kit out and find these. Most parts come in little bags labeled for the step they belong to (like "FOR MOTOR" or "FOR CAMERA") — keep them closed until that step!

Labeled material list: bottom plate, top plate, USB cables, UNO, GY-521 module, motors, IO expansion board, battery box, ultrasonic sensor and holder, camera module and bracket, line-tracking module, tires
Everything in the V4 kit, labeled — from the ELEGOO Smart Robot Car V4.0 User Manual (Material List, p.2).
Watch the parts tour first: seeing every piece for 30 seconds makes the whole build click.
A quick tour of the parts in the box — official ELEGOO assembly video (≈0:43–1:10).

Build it, milestone by milestone 🚗

Eight chunks, in order. Each one shows the finished look, names the part it adds, and tells you where to find that moment in the official video. Follow your paper manual for the exact screws in between.

1

🧩 Lay out the parts & peel the film

Spread all the parts out so you can see them. Then look closely at the two big black plates — they're wrapped in a thin protective film. Peel it off both sides of both plates before you build anything. It pulls off like a sticker.

The top and bottom plates with the note: Attention, remove the protective film before assembling
"Remove the protective film before assembling" — ELEGOO V4 User Manual (p.3).
Do this first! If you build the car with the film still on, you can't peel it later — it's stuck under all the parts. Peel now while the plates are bare.
In the video: the parts get laid out around 0:43.
2

💪 Motors + wheels — the muscles

Each yellow motor is a tiny muscle that spins one wheel. You'll bolt all four motors to the bottom plate, facing outward, using the long screws and the little aluminium blocks from the bag marked "FOR MOTOR". The red and black wires should point inward so you can plug them in later.

Four yellow motors lined up above the bottom plate with screws pointing down into the plate's mounting holes
All four motors mounting onto the bottom plate — ELEGOO V4 User Manual "Assemble the Motor" (p.5).
In the video: motors go on around 1:29.
3

👀 Line-tracking module — the floor-watcher

Flip to the bottom plate and add the line-tracking module — the little board with three eyes that face the floor. It uses short pillars (standoffs) so it hangs just above the ground, ready to spot a black line later. Parts come from the bag marked "FOR UNO, LINE TRACKING".

The line-tracking module with its three sensor eyes mounting under the front of the bottom plate on four standoffs
The line-tracking module going onto the bottom plate — ELEGOO V4 User Manual "Assemble the Line-tracking Module" (p.6).
In the video: the line-tracking module is around 2:08.
4

🧠 The boards — the brain

Now the brain! First clip the tiny blue GY-521 chip onto the big IO expansion board — that chip is the car's sense of balance (it knows which way is up and which way is straight). Then mount the expansion board, and stack the UNO underneath. Together these are the computer that runs everything.

The GY-521 module and copper standoff being added to the IO expansion board, then the board lowering onto the chassis with the UNO
GY-521 + IO expansion board + UNO — ELEGOO V4 User Manual "Assemble the Expansion Board and UNO" (p.7).
Set the GY-521 flat: push the little chip down so it sits level on its pins, not tilted. If it's crooked, the car won't know "straight" and will drive in curves.
In the video: GY-521 + expansion board around 2:30, and the UNO around 2:47.
5

🔋 Battery box — the heart

Bolt the black battery box (the heart) onto the chassis with two screws and nuts from the bag marked "FOR CELL BOX, TIRES". This is what powers the whole car. Leave its wire loose for now — we'll plug everything in during the wiring step.

The black ELEGOO battery box lowering onto the chassis with two screws, its red-and-black power wire hanging free
The battery box mounting onto the chassis — ELEGOO V4 User Manual "Assemble the Battery Box" (p.10).
In the video: the battery box goes on around 3:08.
6

👀 Camera, ultrasonic & servo head — the eyes

Time for the eyes! Build the camera onto its bracket, then add the ultrasonic sensor (the part that looks like two round eyes) on top of the blue SG90 servo. The servo is a little motor that lets the head turn left and right so the car can look around.

The camera module, camera bracket, screws and 4-pin cable, with the camera mounting onto its bracket
Building the camera onto its bracket — ELEGOO V4 User Manual "Assemble the Camera Module" (p.12).
The finished ultrasonic sensor and camera head on the SG90 servo lowering onto the top plate
The finished sensor head mounting onto the top plate — ELEGOO V4 User Manual "Assemble the Ultrasonic Sensor Module" (p.14).
Tiniest screws of the whole build: the ultrasonic "eyes" use 1.6 mm screws and nuts — really small. Hold them with the screwdriver tip, go slowly, and grab a grown-up if your fingers are too big for them. (This is a perfect ask-an-adult moment.)
In the video: the servo head is around 3:44, and the camera/ultrasonic work runs roughly 3:34–4:30.
7

🔌 Wiring the cables — connect it all up

Now plug everything into the brain board: the four motors, the line-tracking module, the servo, the ultrasonic sensor and the battery. Each cable has a labeled port on the board. The picture below is your map of which plug goes where.

Wiring diagram showing the four motors connecting to ports M1–M4, the SG90 servo to servo1, plus the ultrasonic, camera, line-tracking module and battery box around the control board
The wiring map — which cable plugs into which port — ELEGOO V4 User Manual "Wiring Diagram" (p.17).
Connectors are keyed: every plug fits its socket only one way. Line up the shape, push gently, and never force it — if it won't seat, turn it around and try again. Match each motor to its labeled port (M1–M4) so the car drives straight, not sideways.
In the video: wiring starts around 5:17.
8

🏁 Join the two plates + add the tires

The home stretch! Stand the tall copper standoffs on the bottom plate, then lower the top plate on and screw it down — now your car has two decks. Finally, push the four big tires onto the motor shafts and lock them on with the self-tapping screws. Tuck any loose wires inside as you close it up.

The top plate with the sensor head lowering onto the standoffs above the wired-up bottom plate
Joining the top plate onto the standoffs — ELEGOO V4 User Manual (p.22).
The four tires being pushed onto the motor shafts of the assembled car, with four self-tapping screws
Pushing on the four tires — ELEGOO V4 User Manual "Assemble the Tires" (p.23).
In the video: the plates join around 7:11 and the tires go on around 7:24 — right before the big reveal. You're basically done! 🎉

If something's not working

A motor won't sit flush against the plate

Something is usually caught underneath — check that the little aluminium block and the motor's wires aren't pinched between the motor and the plate. Loosen the screws, wiggle the motor so it sits flat, then tighten again evenly (a little on each screw, back and forth) so it doesn't end up crooked.

A cable plug won't push into its socket

Don't force it! The plugs are keyed, meaning they only fit one way. Look at the little notch or shape on the plug and line it up with the socket, then press gently and straight down. If it still won't go, you're probably at the wrong port — check the wiring map above and find the matching label.

I have leftover screws at the end

A few spare screws and nuts in the kit are totally normal — manufacturers add extras in case one rolls away. But if you have a lot left, flip back through the manual and check each milestone: a missing screw usually means a part is loose. Give the motors, boards and sensor head a gentle wiggle to make sure nothing is wobbly.

The plates won't close up — something's in the way

It's almost always a cable. Before pressing the top plate down, gently tuck the wires toward the middle so they sit between the decks instead of poking out. Make sure no plug is squashed against a standoff.

Level up 🚀

Charged and built? Power it on — that was Lesson 1: set it down flat, slide the switch to ON, and let it find "straight". Walk around your finished car and find all four parts again: 🧠 brain, 💪 muscles, 👀 eyes, 🔋 heart. Next session you'll drive it — and soon you'll teach it to follow a line and dodge obstacles all by itself. You built a robot. That's a big deal! 🎉