Print PDF
Favorite
Email
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.
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.
Remove these ads by
Signing UpStep 1Beg, 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.
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.
| « Previous Step | Download PDFView All Steps | Next Step » |
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!
On my DC garden layout, this might be perfect.
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.
http://www3.sympatico.ca/kstapleton3/751D.HTM
I haven't put the accelerometer readings to use yet. Maybe I could use a throwing action to make the turnouts switch?
Looks good. Nice low-angle action shot.
Ken
The last one.
will have to look into buying an arduino
I love how hackable the wiimote and nunchuck attachment are. They have tons of uses yet to be unlocked!