Control Your Robot Using a Wii Nunchuck (and an Arduino)

After wearing myself out playing Wii Boxing I got to thinking wouldn't it be great if I could use this to control my robot, (looking to my left hand).

Looking around the internet I found a bevy of people doing similar things, (links to everyone just below the video). So what follows is a re-packaging of all their hard work, resulting in a robot controllable by both the Wii nunchuck's joystick or more interestingly its accelerometers.

A quick video of my Arduino Controlled Servo Robot - (SERB) being controlled by a Wii nunchuck.

(resources)

• (here) - Arduino Code - Chad at WindMeadows.com has written excellent arduino code for reading the Wii nunchuck. Code which I have included pretty much verbatim in this project. if you're interested in more technical details this is where to look.
• (here) - Nunchuck Details - WiiLi.org has a great wiki about all things Wii, this is a link to a page that describes the nunchucks protocol and how to calibrate your nunchuck.
• (here) - WiiChuck Adapter - Tod of todbot.com very kindly produced a small adapter to make plugging your nunchuck into a breadboard particularly easy.

(similar projects)

• (here) - Wireless Nunchuck Control - Frank over at Society of Robots went one step further adding a wireless link so he can control his Arduino robot with all the tilt and twist fun from afar.
• (here) - Nunchuck Controlled Pan and Tilt Camera - Using a Nunchuck and an Arduino to control the pan and tilt of a camera.
• (here) - Nunchuck and Arduino Controlled Canoe - Finally a rather epic project that uses an Arduino, nunchuck, servos and small trolling motor to drive a Canoe.

(if you have an Arduino nunchuck project you've completed drop me a line and it can be added here)
(shameless plug)
To check out more of our lovely open source projects - oomlout.com

Step 1: Parts & Tools

Only a few parts to collect before we get wiring and programming

Robot - (Arduino Controlled Servo Robot - (SERB) )
( build your own , or purchase a lovely kit ($175)

• We use an Arduino Controlled Servo Robot - (SERB) however any Arduino powered dual servo robot will work. Other options (here)

Electronics - ($24)

• Wii Nunchuck - ($20) - (Amazon) , or at your closest Blockbuster or CircuitCity
• WiiChuck Adapter - ($4) - A small circuit board that allows you to plug your nunchuck into a breadboard without modifying it. (if you don't want to use your nunchuck on your Wii you can save yourself four dollars and simply cut the connector off and plug the wires directly into your breadboard) - (FunGizmos)
• Assorted pieces of Breadboard wire - (22 AWG solid)

That's it onto Wiring it up

Comments

[amasinggray]

wow, just... Wow!

[area36]

#include
#include

#undef int
#include

uint8_t outbuf[6]; // array to store arduino output
int cnt = 0;
int ledPin = 13;

void
setup ()
{
beginSerial (19200);
Serial.print ("Finished setup\n");
Wire.begin (); // join i2c bus with address 0x52
nunchuck_init (); // send the initilization handshake
}

void
nunchuck_init ()
{
Wire.beginTransmission (0x52); // transmit to device 0x52
Wire.send (0x40); // sends memory address
Wire.send (0x00); // sends sent a zero.
Wire.endTransmission (); // stop transmitting
}

void
send_zero ()
{
Wire.beginTransmission (0x52); // transmit to device 0x52
Wire.send (0x00); // sends one byte
Wire.endTransmission (); // stop transmitting
}

void
loop ()
{
Wire.requestFrom (0x52, 6); // request data from nunchuck
while (Wire.available ())
{
outbuf[cnt] = nunchuk_decode_byte (Wire.receive ()); // receive byte as an integer
digitalWrite (ledPin, HIGH); // sets the LED on
cnt++;
}

// If we recieved the 6 bytes, then go print them
if (cnt >= 5)
{
print ();
}

cnt = 0;
send_zero (); // send the request for next bytes
delay (100);
}

// Print the input data we have recieved
// accel data is 10 bits long
// so we read 8 bits, then we have to add
// on the last 2 bits. That is why I
// multiply them by 2 * 2
void
print ()
{
int joy_x_axis = outbuf[0];
int joy_y_axis = outbuf[1];
int accel_x_axis = outbuf[2] * 2 * 2;
int accel_y_axis = outbuf[3] * 2 * 2;
int accel_z_axis = outbuf[4] * 2 * 2;

int z_button = 0;
int c_button = 0;

// byte outbuf[5] contains bits for z and c buttons
// it also contains the least significant bits for the accelerometer data
// so we have to check each bit of byte outbuf[5]
if ((outbuf[5] >> 0) & 1)
{
z_button = 1;
}
if ((outbuf[5] >> 1) & 1)
{
c_button = 1;
}

if ((outbuf[5] >> 2) & 1)
{
accel_x_axis += 2;
}
if ((outbuf[5] >> 3) & 1)
{
accel_x_axis += 1;
}

if ((outbuf[5] >> 4) & 1)
{
accel_y_axis += 2;
}
if ((outbuf[5] >> 5) & 1)
{
accel_y_axis += 1;
}

if ((outbuf[5] >> 6) & 1)
{
accel_z_axis += 2;
}
if ((outbuf[5] >> 7) & 1)
{
accel_z_axis += 1;
}

Serial.print (joy_x_axis, DEC);
Serial.print ("\t");

Serial.print (joy_y_axis, DEC);
Serial.print ("\t");

Serial.print (accel_x_axis, DEC);
Serial.print ("\t");

Serial.print (accel_y_axis, DEC);
Serial.print ("\t");

Serial.print (accel_z_axis, DEC);
Serial.print ("\t");

Serial.print (z_button, DEC);
Serial.print ("\t");

Serial.print (c_button, DEC);
Serial.print ("\t");

Serial.print ("\r\n");
}

// Encode data to format that most wiimote drivers except
// only needed if you use one of the regular wiimote drivers
char
nunchuk_decode_byte (char x)
{
x = (x ^ 0x17) + 0x17;
return x;
}

[area36]

//START OF NUNCHUCK PREAMBLE - For more in depth information please visit the original source of this code http://www.windmeadow.com/node/42
//-------------------------------------------------
/*
* Wiring Details
* white - ground
* red - 3.3+v - 5 volts seems to work
* green - data - Analog 4
* yellow - clock - Analog 5
*/

#include
#include

#undef int
#include

uint8_t outbuf[6]; // array to store arduino output
int cnt = 0; // counter used for nunchuck comunication
int ledPin = 13;

int nunchuckValues[] = {0,0,0,0,0,0,0,0,0,0}; //An array to store the nuncheck values

/*
* The index of each value within the nunchuckValues[] array
* ie. XSTICK value is stored at nunchuckValues[XSTICK] (0)
*/
#define XSTICK 0 //The joystick values
#define YSTICK 1
#define XAXIS 2 //The three accelerometer values
#define YAXIS 3
#define ZAXIS 4
#define ZBUTTON 5 //Front button values (0 when pressed)
#define CBUTTON 6
#define XAXISDELTA 7 //Change in accelerometer data from last read;
#define YAXISDELTA 8
#define ZAXISDELTA 9

//Nunchuck G calculating Constants
/*
* For scaling the raw values from the nunchuck into G values
* Details on callibration and the maths can be found at
* http://www.wiili.org/index.php/Motion_analysis
(Copied from http://www.wiili.org/index.php/Motion_analysis)
Zero Points
x_0 = (x_1 + x_2) / 2\,
y_0 = (y_1 + y_3) / 2\,
z_0 = (z_2 + z_3) / 2\,
One G points
x = \frac{x_{raw} - x_0}{x_3 - x_0}
y = \frac{y_{raw} - y_0}{y_2 - y_0}
z = \frac{z_{raw} - z_0}{z_1 - z_0}
*/

/* Not all of these are used and could be deleted (kept to make interpretting math's
* Easier 0-Zero G Value 1-Value when laying on table 2-Value when resting on nose
* 3-Value when resting on side (left side up)
*/
#define X0 500
#define X1 500
#define X2 500
#define X3 711

#define Y0 465
#define Y1 481
#define Y2 621
#define Y3 449

#define Z0 578
#define Z1 785
#define Z2 575
#define Z3 582

//END OF NUNCHUCK PREAMBLE - For more in depth information please visit the original source of this code http://www.windmeadow.com/node/42
//------------------------------------------------------

//--------------------------------------------------------------------------
// START OF ARDUINO CONTROLLED SERVO ROBOT (SERB) PREAMBLE
#include

#define LEFTSERVOPIN 10
#define RIGHTSERVOPIN 9

#define MAXSPEED 10 //due to the way continuous rotation servos work maximum speed is reached at a much lower value than 90 (this value will change depending on your servos) (for Parallax servos)

Servo leftServo;
Servo rightServo;

int leftSpeed = 100; //sets the speed of the robot (left servos)
//a percentage between -MAXSPEED and MAXSPEED
int rightSpeed = 100; //sets the speed of the robot (both servos)
//a percentage between -MAXSPEED and MAXSPEED
int speed = 100; //used for simple control (goForward, goBackward, goLeft, and goRight
//a percentage between 0 and MAXSPEED


// END OF ARDUINO CONTROLLED SERVO ROBOT (SERB) PREAMBLE
//--------------------------------------------------------------------------

long lastPrint; //a long variable to store the time the wiimote state was last printed
#define PRINTINTERVAL 1000 //the number of milliseconds between outputting the nunchuck state over the usb port
#define DEADBAND 20 //A percentage away from center that is interpretted as still being zero


void setup(){
Serial.begin(9600); //Starts the serial port (used for debuging however makes servos jumpy)
nunchuck_init (); // send the nunchuck initilization handshake
serbSetup(); // adds the servos and prepares all SERB related variables
lastPrint = millis();
}


void loop(){
readNunchuck(); //Reads the current state of the nunchucks buttons and accelerometers
if(!getNunValue(ZBUTTON)){
moveWiiAcelerometer(); //moves the wii deoending on the nunchucks acceleration values
}else{
moveWiiJoystick();
}
if((millis() - lastPrint) > PRINTINTERVAL){ //If a second has passed since last printing nunchuck values print them
printData(); //print nunchuck values
Serial.println(); //add an enter
lastPrint = millis(); //store current time as lastPrint
}

}

void moveWiiAcelerometer(){
moveDifferential(getYGs() * (float)100,getXGs()*(float)100);
}

void moveWiiJoystick(){
moveDifferential(map(getNunValue(YSTICK),30,220,-100,100),map(getNunValue(XSTICK),30,220,-100,100));
}

//Takes in a speed and a direction input (like a joystick) and translates it to speed commands
void moveDifferential(int speed1, int direction1){
speed1 = deadBandFilter(speed1);
direction1 = deadBandFilter(direction1);
setSpeedLeft(speed1 + direction1);
setSpeedRight(speed1 - direction1);
}

int deadBandFilter(int value){
if(value > -DEADBAND && value < DEADBAND){value = 0;}
else{
if(value > 0){value = value - DEADBAND * 100 / (100-DEADBAND);}
else{value = value + DEADBAND * 100 / (100-DEADBAND);}
}
return value;
}


//START OF NUNCHUCK ROUTINES
//-------------------------------------------------------------------------------------------------------


//Calculates and returns the xAxis acceleration in Gs
float getXGs(){
return ((float)getNunValue(XAXIS) - X0) / (X3 - X0);
}

//Calculates and returns the yAxis acceleration in Gs
float getYGs(){
return ((float)getNunValue(YAXIS) - Y0) / (Y2 - Y0);
}

//Calculates and returns the zAxis acceleration in Gs
float getZGs(){
return ((float)getNunValue(YAXIS) - Z0) / (Z1 - Z0);
}

//START OF NUNCHUCK Reading CODE - For more in depth information please visit the original source
//of this code http://www.windmeadow.com/node/42
//---------------------------------------------------------------
void readNunchuck(){
Wire.requestFrom (0x52, 6); // request data from nunchuck
while (Wire.available ()) {
outbuf[cnt] = nunchuk_decode_byte (Wire.receive ()); // receive byte as an integer
digitalWrite (ledPin, HIGH); // sets the LED on
cnt++;
}

// If we recieved the 6 bytes, then go print them
if (cnt >= 5) {
nunchuckValues[XSTICK] = outbuf[0];
nunchuckValues[YSTICK] = outbuf[1];
int tempNun_xAxis = outbuf[2] * 2 * 2;
int tempNun_yAxis = outbuf[3] * 2 * 2;
int tempNun_zAxis = outbuf[4] * 2 * 2;
nunchuckValues[ZBUTTON] = 0;
nunchuckValues[CBUTTON] = 0;

// byte outbuf[5] contains bits for z and c buttons
// it also contains the least significant bits for the accelerometer data
// so we have to check each bit of byte outbuf[5]
if ((outbuf[5] >> 0) & 1) { nunchuckValues[ZBUTTON] = 1; } //checking if Z button is pressed (0=pressed 1=unpressed)
if ((outbuf[5] >> 1) & 1) { nunchuckValues[CBUTTON] = 1; } //checking if C button is pressed (0=pressed 1=unpressed)
if ((outbuf[5] >> 2) & 1) { tempNun_xAxis += 2; } //adding second least significant bit to x_axis
if ((outbuf[5] >> 3) & 1) { tempNun_xAxis += 1; } //adding least significant bit to x_axis
if ((outbuf[5] >> 4) & 1) { tempNun_yAxis += 2; } //adding second least significant bit to y_axis
if ((outbuf[5] >> 5) & 1) { tempNun_yAxis += 1; } //adding least significant bit to x_axis
if ((outbuf[5] >> 6) & 1) { tempNun_zAxis += 2; } //adding second least significant bit to z_axis
if ((outbuf[5] >> 7) & 1) { tempNun_zAxis += 1; } ////adding least significant bit to x_axis

nunchuckValues[XAXISDELTA] = tempNun_xAxis - nunchuckValues[XAXIS];
nunchuckValues[XAXIS] = tempNun_xAxis;
nunchuckValues[YAXISDELTA] = tempNun_yAxis - nunchuckValues[YAXIS];
nunchuckValues[YAXIS] = tempNun_yAxis;
nunchuckValues[ZAXISDELTA] = tempNun_zAxis - nunchuckValues[ZAXIS];
nunchuckValues[ZAXIS] = tempNun_zAxis;
}
cnt = 0;
send_zero (); // send the request for next bytes
}

int getNunValue(int valueIndex){
return nunchuckValues[valueIndex];
}

void nunchuck_init (){
Wire.begin (); // join i2c bus with address 0x52
Wire.beginTransmission (0x52); // transmit to device 0x52
Wire.send (0x40); // sends memory address
Wire.send (0x00); // sends sent a zero.
Wire.endTransmission (); // stop transmitting
}

void send_zero () {
Wire.beginTransmission (0x52); // transmit to device 0x52
Wire.send (0x00); // sends one byte
Wire.endTransmission (); // stop transmitting
}

// Encode data to format that most wiimote drivers except
// only needed if you use one of the regular wiimote drivers
char nunchuk_decode_byte (char x) {
x = (x ^ 0x17) + 0x17;
return x;
}

//END OF NUNCHUCK CODE - For more in depth information please visit the
//original source of this code http://www.windmeadow.com/node/42
//---------------------------------------------------------------

//------------------------------------------------------------------------
//START OF ARDUINO CONTROLLED SERVO ROBOT (SERB) ROUTINES

/*
* sets up your arduino to address your SERB using the included routines
*/
void serbSetup(){
setSpeed(speed);
pinMode(LEFTSERVOPIN, OUTPUT); //sets the left servo signal pin
//to output
pinMode(RIGHTSERVOPIN, OUTPUT); //sets the right servo signal pin
//to output
leftServo.attach(LEFTSERVOPIN); //attaches left servo
rightServo.attach(RIGHTSERVOPIN); //attaches right servo
goStop();
}


/*
* sets the speed of the robot between 0-(stopped) and 100-(full speed)
* NOTE: speed will not change the current speed you must change speed
* then call one of the go methods before changes occur.
*/
void setSpeed(int newSpeed){
if(newSpeed >= 100) {newSpeed = 100;} //if speed is greater than 100
//make it 100
if(newSpeed <= 0) {newSpeed = 0;} //if speed is less than 0 make
//it 0
speed = newSpeed * MAXSPEED / 100; //scales the speed to be
//between 0 and MAXSPEED
}

/*
* sets the speed of the robots rightServo between -100-(reversed) and 100-(forward)
* NOTE: calls to this routine will take effect imediatly
*/
void setSpeedRight(int newSpeed){
if(newSpeed >= 100) {newSpeed = 100;} //if speed is greater than 100
//make it 100
if(newSpeed <= -100) {newSpeed = -100;} //if speed is less than -100 make
//it -100
rightSpeed = newSpeed * MAXSPEED / 100; //scales the speed to be
//between -MAXSPEED and MAXSPEED
rightServo.write(90 - rightSpeed); //sends the new value to the servo
}

/*
* sets the speed of the robots leftServo between -100-(reversed) and 100-(forward)
* NOTE: calls to this routine will take effect imediatly
*/
void setSpeedLeft(int newSpeed){
if(newSpeed >= 100) {newSpeed = 100;} //if speed is greater than 100
//make it 100
if(newSpeed <= -100) {newSpeed = -100;} //if speed is less than -100 make
//it -100
leftSpeed = newSpeed * MAXSPEED / 100; //scales the speed to be
//between -MAXSPEED and MAXSPEED
leftServo.write(90 + leftSpeed); //sends the new value to the servo
}

/*
* sends the robot forwards
*/
void goForward(){
leftServo.write(90 + speed);
rightServo.write(90 - speed);
}

/*
* sends the robot backwards
*/
void goBackward(){
leftServo.write(90 - speed);
rightServo.write(90 + speed);
}

/*
* sends the robot right
*/
void goRight(){
leftServo.write(90 + speed);
rightServo.write(90 + speed);
}

/*
* sends the robot left
*/
void goLeft(){
leftServo.write(90 - speed);
rightServo.write(90 - speed);
}

/*
* stops the robot
*/
void goStop(){
leftServo.write(90);
rightServo.write(90);
}
//END OF ARDUINO CONTROLLED SERVO ROBOT (SERB) ROUTINES
//---------------------------------------------------------------------------


//START OF PRINT ROUTINES (can delete if not using)
//---------------------------------------------------------------

//Prints the Nunchucks last read data (must call NUN_readNunchuck(); before calling
void printData(){
Serial.print("XJoy= ");Serial.print (getNunValue(XSTICK), DEC); Serial.print ("\t");
Serial.print("YJoy= ");Serial.print (getNunValue(YSTICK), DEC); Serial.print ("\t");
Serial.print("XGs= ");Serial.print (getXGs() * 1000, DEC); Serial.print ("\t");
Serial.print("YGs= ");Serial.print (getYGs() * 1000, DEC); Serial.print ("\t");
Serial.print("ZGs= ");Serial.print (getZGs() * 1000, DEC); Serial.print ("\t");
Serial.print("ZBut= ");Serial.print (getNunValue(ZBUTTON), DEC); Serial.print ("\t");
Serial.print("YBut= ");Serial.print (getNunValue(CBUTTON), DEC); Serial.print ("\t");
}

//END OF PRINT ROUTINES
//--------------------------------------------------------------------

[area36]

does anyone have code that works for this!?

[biomech75]

Fix the code !!! and post it

[captainrwooten]

If you are using Arduino 1.0 IDE you will have to change some commands. The error codes will tell you which ones. Also the code doesn't specify some registers, you'll have to plug those in yourself. Good luck.

[jac.diamond]

Is the code posted alright? Im thinking of doing this but i dont want to buy the stuff until i know its alright.

[carlosanchez]

I found the original code Here you go! http://oomlout.com/tmp/SERB_WiiNunChuckControl.txt

[doby162]

This is an awesome guide!! Thanks oomlout and also thanks to carlosanchez for providing the uncorupted code :P I will definantly link to this in the instructable I make with my nunchuck :D

[Jordan arduino]

Guys could you give me the website for the circuit

[wamj]

i think that the next logical step would be hide an xbee, a rechargeable battery, and charging circuit to make a wireless version

[tmj61]

Is the kit no longer available? when i try to go to the l "purchase a lovely kit" link it does not work.

[Hoolaput]

why would you want to use the 5v if there's a 3v3 (3.3v) on the arduino beside the reset and 5v?

[carlosanchez]

The 3.3V is supplied by the FTDI chip. Therefore it will only be available if the Arduino is powered via USB. If it is connecter to a battery, the chip will be bypassed.

[Asuraku]

 This code is an absolute mess and I can't seem to figure out how to fix it. Could someone post an un-scrambled working copy?

[carlosanchez]

http://oomlout.com/tmp/SERB_WiiNunChuckControl.txt

[Mdob]

Agreed, code is screwed; lets hope that Oomlout fixes it soon.

[carlosanchez]

http://oomlout.com/tmp/SERB_WiiNunChuckControl.txt

[carlosanchez]

Hello! Would it be possible to post the code in a .pde file? The one pasted in the Instructable is scrambled in the beggining and is really hard to fix. Thanks!

[Dannne11]

how doe you connect the servos???

[xava100]

someone should try this with the classic controller since there isnt any other use for it

[isambard1000]

 Hi Oomlout, the Arduino code seems to have got scrambled... can you repost it or email it to me. Thanks!

[TXTCLA55]

Hello again I just built the robot and well something is screwed up. I built it to your diagrams, pictures, and code and all I got was this:

http://www.flickr.com/photos/14462918@N03/3970656962/

The video pretty much shows the problem...NOTHING WORKS! By the way I just spent around $100 on this project and I was hoping that it would work.

[tristantech]

If you want to save a few bucks but dont want to cut your nunchuck cord (it would be a shame to ruin such a nice toy) just take some double-sided copper clad board and use a dremel to carve traces like in the adapter the author used. I used to trick with a gamecube controller.

[ZeusFury]

i think i am missing _SERB_WiiNunchuckControl.hex because i got this error ....FR0N58YFUI0OXF5\_SERB_WiiNunchuckControl\applet\_SERB_WiiNunchuckControl.hex': No such file...FR0N58YFUI0OXF5\_SERB_WiiNunchuckControl\applet/_SERB_WiiNunchuckControl.cpp:133: undefined reference to `beginSerial'... i would really like some help on this pleas

[oomlout]

Hi zeus (and fred) Sorry not to get back sooner. The problem has arisen from an update in the Arduino IDE. There is a conflict between the Serial library and another library we are using. To fix it simply remove all references to the Serial library and the include at the top. Or the easy option is we have changed the code on this page. Copy and paste the updated code (above) into an empty sketch and it should compile. Sorry about the error. Regards Stuart

[fred_thedog]

I get the same error as TXTCLA55. Haven't spent any time trying to find the problem yet though.

[ZeusFury]

avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

i got these errors can some 1 help

[evmaster297]

with a wire less nun chuck, it looks like an awesome coaster to me!!! but eventually a dog toy

[TXTCLA55]

Errpr code: arduino cannot determine program size, says it cannot find the files needed

[oomlout]

Hi TXTCL55; Sorry to hear about the error code, its never fun when something doesn't work. Something to try, is rather than downloading the files, copy and paste the code from this page into the Arduino IDE and see if it compiles. Sometimes this works (also "cannot determine program size" is sometimes only a warning and you may be able to upload after receiving it) Hope that was helpful, shoot us an e-mail at [e-mail] if that doesn't work and we'll try and get things sorted.

[TXTCLA55]

nope same error. I tried deleting the stuff at the end ( labled "delete if not using") and I still got error codes. I'll try sending a email to the one you suggested.

[Foaly7]

Dude. Totally use a wireless WiiChuck and tweak its range and mount a camera on your 'bot and you can have a surveillance bot!

[renamecor]

How cool is that, I'm off to see if I can find my daughters WREX and insert a wii nunchuck where the sun don't shine.

What about wireless nunchuck - WIreless Nunchuck

[YummyPancakes]

Very, very cool! I just got a Wii for Christmas, and "Santa" accidentally brought us an extra Nunchuck and Wiimote. Together with my brand new Arduino Duemillanove, this is perfect! Thank you, and Merry Christmas!

[ririgoyen]

you should look at Nyko's Kama (Wireless Nunchuck). You'll make your robot wireless in 4 seconds.

[explosivemaker]

.....definitely.....a remote control car with a motion controller would be sweet....or a plane....

[fwjs28]

ha!nice mug...lol... here my version.... 1take wii mote and robot 2 tie wii mote to robot 3 drag wii mote and make robot move.......

[cantthinkof bettername]

I just posted a comment almost the same, because I didn't read the comments first.

[fwjs28]

ha..yea i see that....i like the mug its hilarious...