Build an RC Car with Wii Remote + Arduino + LEGO (Part 1): Parts Selection

Table of contents

1. Wii Remote + Arduino + LEGO RC Car (Part 1): Parts Selection
2. Wii Remote + Arduino + LEGO RC Car (Part 2): Driving DC Motors
3. Wii Remote + Arduino + LEGO RC Car (Part 3): Bluetooth Dongle via USB Host Shield
4. [Finished!] Wii Remote + Arduino + LEGO RC Car (Part 4): Controlling DC Motors with the Wii Remote

I'm building things I can play with together with my kids.
When it comes to electronics toys, RC cars are the obvious choice.

That said, standard RC controllers can be tricky for small children to operate.
So I decided to control the car using the accelerometer in a Wii Remote — tilt to drive.

The Wii Remote connects to Arduino over Bluetooth, and DC motors handle the drivetrain.
There are a bunch of useful Arduino techniques packed into this build, so it also works well as an Arduino learning project.
I'll try to explain everything clearly enough for beginners.

Here's the finished result:


Here's the build plan:

1. Decide on the overall design and gather parts


2. Drive DC motors with Arduino


3. Get a Bluetooth USB dongle working via USB Host Shield


4. Control the DC motors with the Wii Remote

Let's start with the overall design.


For a DIY RC car, tracks (caterpillar treads) are far easier and cheaper than wheels.
I'm using the tracks and frame from a LEGO crane set.

With wheels you'd need servo motors to build a steering mechanism, but with tracks
you can turn left and right using just two DC motors — cheaper parts and a much more forgiving frame.

The Wii Remote communicates over Bluetooth.
You could use a dedicated Bluetooth module for Arduino, but I deliberately went with
a USB Host Shield + PC Bluetooth dongle combo instead.

The upside: if I ever get bored with the project, the dongle can be repurposed on a Raspberry Pi,
or the USB Host Shield can be used to control a digital camera over MTP.
…That's my excuse, anyway.

Now let's go through each component.

Wii Remote

You probably already have one or two gathering dust somewhere.
If you don't, I'd skip this build — it's not worth buying one just for this project.

LEGO Technic Crawler Crane 9391

Check on Amazon

Any LEGO set with tracks will do, but this crane set used to be the cheapest way to get tracks and a frame.
…That said, the price has crept up to around ¥9,000 in recent years. It was about ¥2,000 a year ago.
The weak yen is brutal. Buy when the price is low.

Arduino UNO

Check on Amazon

If you're buying your first Arduino, the UNO is the one to get.
Nearly every tutorial uses the UNO as its reference board, and shields are easy to find.
Having one UNO also makes it much easier to build your own Arduino-compatible boards down the road.

My first Arduino came from a starter kit that included a breadboard, USB cable, resistors, LEDs, and a speaker —
everything you need to get through the basics in one box.

USB Host Shield

Check on Amazon

This one can be a pain. Sticking to a Circuits@Home-compatible board is the safer choice.

I bought the Sparkfun version and found it wasn't compatible with the Circuits@Home library,
which meant modding a trace on the PCB.
Honestly, it was a bit of a thrill — recommended if you enjoy fighting surface-mount boards with a soldering iron.

If you end up with the Sparkfun version, this site has a detailed modification guide.

Bluetooth USB Dongle

Check on Amazon

We're deliberately using a USB dongle for the Bluetooth connection.
Planex is the brand of choice — it's cheap. That's the whole reason.
If you already have a dongle lying around, just use that.

USB Battery Pack (for smartphones)

Used to run the Arduino UNO untethered from a PC.
Any brand works, but look for one that meets these conditions:

• Detachable power cable, or a pack where the cable tucks away.


• Smaller than the Arduino UNO. As thin as possible.


• Replaceable USB cable.
  (Smaller boards like the Arduino Nano or Raspberry Pi use micro USB.)

Motor Driver IC

A driver IC chip to control the DC motors.
You'll need two.

Available from Akizuki Denshi (Japanese electronics retailer).

Battery Holder

Used to power the DC motors.
The Arduino power supply and the DC motor power supply must be kept on separate circuits.

Just because Arduino is USB-powered doesn't mean you can drive motors directly from its output pins —
the current draw will fry the board.

I'll go into more detail on this in the next installment.

Any holder will do, but I recommend one that fits four AA batteries side by side.
Four Eneloop cells in series (1.2V × 4 = 4.8V) lets you power the Arduino from its pin socket instead of USB,
consolidating everything into one battery. That said, the voltage is a bit unstable this way, so I wouldn't rely on it long-term.

Akizuki Denshi is much cheaper than Amazon for this one.

Tamiya Twin-Motor Gearbox

Check on Amazon

You could skip this, but the motors alone won't have enough torque to move the tracks.

All in, the parts come to roughly ¥10,000 (~$65 USD).

"You could just buy a ready-made RC car for less effort and money" — I know.

But the point isn't to end up with an RC car. The point is to build one and have fun doing it.

Besides, every component here can be repurposed for something else when you're done.
That's how I talk myself into it.

Next time, we actually start building.