Picture of Wii Nunchuk Controlled Model Train
Using an Arduino microcontroller, an Adafruit motor shield, and a Wii Nunchuk, you can create a intuitive, programmable, model train controller to run your layout.  Amaze your friends.  Entertain your kids.  Not quite DC, not quite DCC.  You're headed for the hacker lands of PWM (pulse-width modulation).

Why do this?
 - Pulse-width modulation allows smooth operation at slow speeds.
 - Set realistic rates of acceleration and braking.
 - Set maximum speed to avoid derailments.
 - Program operational responses to meet your operating style.
 - Control train based on sensors, auto reversing, whatever.
 - Because you can, and it is cool.

Step 1: Beg, Borrow, or Build

Picture of Beg, Borrow, or Build
You will need to beg, borrow, or build a couple of things, all well documented.  Don't be afraid.

1.  Wii Nunchuk.  - The only part of this that isn't "open source" or completely hackable.  It is, luckly, relatively inexpensive, easy to obtain (you may already have one on hand), and incredibly versatile.  For $20 you are getting:
          2-axis joystick
          3-axis accelerometer
          2 pushbuttons
          Countless hours of Nintendo product engineering (priceless)

2.  WiiChuck Adapter.  - While you can cut your cable to access the wires, your kids will hate you when they go to play Lego StarWars next time.  A couple of bucks will get you an adapter and guilt-free access to a software library written by the guy that came up with it (www.sparkfun.com/commerce/product_info.php), or your could build your own using this Instructable.

3. Arduino Microcontroller - You can buy or build one of these.  They are easy and fun to use, and with the shields, can be put to a number of uses, repeatedly.  They come in a number of variants.  I like the newer Duemilanove since it has USB built in.  Here is one source: www.adafruit.com/index.php

4. Motor Controller - As versatile as the Arduino is, it can't drive a DC motor on it's own.  You can breadboard something together using a H-Bridge chip like the SN754410, as shown here, or buy a shield kit that fits right on the Arduino and comes with software libraries and examples.  I'm using one I built from Adafruit shown here.

5. Model Train - (Sold separately). Or any small DC motor you might want to drive.  I'm actually doing this for a small "switching puzzle" layout I've got built.  It is only 1' x 4', and I want it to be easily (and safely) operated by children.  It involves a lot of slow-speed back-and-forth, unlike the typical full-throttle round-and-round stuff.  You can learn more about the layout on the last page.
chantallex_x7 months ago

Dear ken.

Now is our code completed !! We are very happy about it. But the only problem is that our train doesn't move. Now we think it is because our train only drives with at least 100 V.

What kind of train do you use ? And if we want to buy a new train what kind of detail we have to look for ?

Kind regard,

Claire & Chantalle

chantallex_x8 months ago


I have declared the wire but now we get these errors, I hope you can help us!

sketch_trein-nunchuk.ino: In function 'void nunchuck_init()':
sketch_trein-nunchuk.ino:35: error: 'class TwoWire' has no member named 'send'
sketch_trein-nunchuk.ino:36: error: 'class TwoWire' has no member named 'send'
sketch_trein-nunchuk.ino: In function 'void nunchuck_send_request()':
sketch_trein-nunchuk.ino:45: error: 'class TwoWire' has no member named 'send'
sketch_trein-nunchuk.ino: In function 'int nunchuck_get_data()':
sketch_trein-nunchuk.ino:65: error: 'class TwoWire' has no member named 'receive'

MakersBox (author)  chantallex_x8 months ago

I would completely abandon my example code and start by going to https://github.com/GabrielBianconi/ArduinoNunchuk and downloading his library (look for the "Download Zip" button).

Unzip the download and copy the 'ArduinoNunchuk' folder, located in the same folder as this 'README' file, to the Arduino libraries folder (Arduino/libraries).

Restart your Arduino IDE and then open the demo code [File]->[Examples]->[ArduinoNunchuk]->[ArdunioNunchukDemo]

Upload the sketch and see if you can get readings from your Chuk, and we'll work from there.

MakersBox (author)  chantallex_x8 months ago

Sounds like it is time to update the sketch to get a working example again.

Shoot me an email at 648.ken@gmail.com and you guys can help me get one written and tested.

chantallex_x8 months ago

I hope somebody is still active. My friend and I are working on this for our assignment for school. But we are having struggles with some errors. I hope somebody can help us.

WiiChuck_Train_Controller.ino: In function 'void nunchuck_init()':

WiiChuck_Train_Controller:32: error: 'Wire' was not declared in this scope

WiiChuck_Train_Controller.ino: In function 'void nunchuck_send_request()':

WiiChuck_Train_Controller:43: error: 'Wire' was not declared in this scope

WiiChuck_Train_Controller.ino: In function 'int nunchuck_get_data()':

WiiChuck_Train_Controller:61: error: 'Wire' was not declared in this scope

We hope somebody knows these errors and can help us.

MakersBox (author)  chantallex_x8 months ago
Hey Guys!

Sounds like a fun class if you get to use an Arduino!

I had compatibility problems with the newer Arduino versions and switched to a newer nunchuk library from:

Take a look at the demo sketch that comes with it.

Let know how it goes!

repkid1 year ago

I love this and might try this myself.

xenonion1 year ago

I put this great controller into use several months ago. I wanted to build another one but adafruit has changed the controller design, is it still compatible with this? Here's the new controller. http://www.adafruit.com/products/1438

Thank You!

MakersBox (author)  xenonion1 year ago

I haven't had a chance to use the new one yet, but it looks like it would work fine for driving a train. Let us know if you try it out!

C.Mahoney3 years ago
very nice project!!
I need some help with the program.
these are the errors that i get:

nunchuck.cpp:324:28: error: nunchuck_funcs.h: No such file or directory
nunchuck.cpp:325:21: error: AFMotor.h: No such file or directory
nunchuck.cpp: In function 'void nunchuck_init()':
wii_train_controller:152: error: 'Wire' was not declared in this scope
nunchuck.cpp: In function 'void nunchuck_send_request()':
wii_train_controller:163: error: 'Wire' was not declared in this scope
nunchuck.cpp: In function 'int nunchuck_get_data()':
wii_train_controller:181: error: 'Wire' was not declared in this scope

Can some one help Please
MakersBox (author)  C.Mahoney3 years ago
It sounds like the sketch can't find the extra libraries. You need to download and install both the motor library from Adafruit and the Nunchuck library. Check the Arduino forum if you need help with that.
when i go to get hub which of the files should i get(motor-shield)? it wont let me download all of them at once and how to i save them properly?
Henry_Best3 years ago
Have you thought about using magnetic reed switches to detect when a train is approaching the end of tracks? All you need is a couple of small bar magnets glued to the underside of the loco and trailing vehicle (for reverse operation). The reed switches, which are very cheap, can be easily disguised as 'between track' fittings and can be painted without affecting their operation. If you're using a common ground, just connect one side of the (normally open) reed switch to that and take the other side back to one of the Arduino pins, held at 5v by a 1k resistor. Poll that pin to detect when it's grounded and apply the brakes! The magnets should have the same orientation as the reed switches (don't have them at right angles to each other) otherwise you may get a double switching as the N and then the S poles move over the switch.
You can also use reed switches for train differentiation. Imagine two locos, one with two magnets spaced 1" apart and the other with the magnets 2" apart. With 3 reed switches spaced 1" and 1" you can detect if switches 1 and 2 are closed at the same time or if switches 1 and 3 are closed at the same time. Simply ground one end of switch 1 and connect the other end to both switches 2 and 3. The outputs of switches 2 and 3 will tell you which train is present.
My idea is for an automatic 'hump' shunting yard. The wagons would have a bar code stuck to the underside and a bar code reader in the hump would read the barcode and switch the points to the appropriate track. I don't yet know how to do this, but I'm sure that it could be done with an Arduino!

Great Instructable Ken, and Dawson Station is an exceptional piece of craftsmanship.
Hello, this is a great project but I cant download the code! could you put another link up so I could get the code please? this link gives me a tmp file!? Regards Richard
MakersBox (author)  mewithaflower4 years ago
I uploaded a zip file. Give it a try.
Works great, i've learnt loads already. cheers dude
randomhand5 years ago
Saw this layout on www.carendt.com. Realy nice job
Has anybody used this with DCC?  I wouln't want to burn out a lot of locos, turnouts,  and other controlled stuff.

On my DC garden layout, this might be perfect.
you probaly will need the entire wii to get the parts cus you will need antennas...... and receavers
Honus5 years ago
Neato -I like it!

It would definitely be cool for slot cars. My little boys have a hard time controlling the car speed and keeping them on the track. One thing you could also do is have lane changing on a routed wood track (or track changing for trains) by using either a solenoid or servo motor to move the track by pressing one of the nunchuck buttons. I wrote some code a couple of years ago that allows access to all the nunchuck functions so I might have to try that out.
MakersBox (author)  Honus5 years ago
You are one step ahead of me.  Operating turnouts is the next step.  I was going to use servos, but then I found this neat little circuit which will use the Atlas remote switches which I already have:


I haven't put the accelerometer readings to use yet.  Maybe I could use a throwing action to make the turnouts switch?
Honus MakersBox5 years ago
I've set up a nunchuck so the accelerometer and joystick functions move servos and the buttons trigger transistors to turn on sounds/lights. I figured for slot cars I'd use the joystick to control acceleration/braking and the buttons could control two lane changers. Don't know what I'd use the accelerometer for....
aseaheru Honus4 years ago
top speed? normaly shunting is a max speed of 15 mi.....
  nice layout! heres a picture of mine (still in progress)
J&J tech 014.jpg
MakersBox (author)  inventordude145 years ago
Has there ever been a layout that wasn't "still in progress"?

Looks good.  Nice low-angle action shot.


The last one.
nothing is ever finished.
never. aways changing. random question, have you heard of Gn15?
aseaheru4 years ago
did not know you wii-d dawson station. cool.
This is handy i hate derailing skelectric cars ! .

will have to look into buying an arduino
Doctor What5 years ago
 What a magnificent application of the Wiimote!

I love how hackable the wiimote and nunchuck attachment are.  They have tons of uses yet to be unlocked!