使用Wii Nunchuk控制双轴云台伺服电机
在这篇文章中,我们将使用Wii nunchuk手柄连接到Arduino,并实现对伺服电机的控制。

简介
偶然在箱子里发现一个旧的Wii Nunchuk手柄,又叫“双节棍”手柄,我想它是否可以用来控制Arduino,查阅了相关资料,确定Nunchuk手柄支持I2C方式连接到Arduino, 通过不断地研究深入,最后从todbot.com等网站上找到了相关的控制Will nunchuk的代码,于是就将代码移植过来,实现了 Will nunchuk 对伺服电机的控制!
Wii Nunchuk接口定义
把Wii Nunchuk和Arduino连接起来有几种方法,我们可以买一个Wii nunchuk的适配器,或者像剪断连接线,确保手柄再不需要和Wii连接使用了。本文采用了剪断线的方法,剪线之后再焊接了插针到nunchuk的连线,这样就可以和面包板更好的连接了。下图是Wii Nunchuk的接口定义 。

Wii Nunchuk连接Arduino
- 手柄白线 (GND) –> Arduino GND
- 手柄红线 ( +5V ) –> Arduino 5V
- 手柄绿线 (SDA) –> 模拟引脚 4 或者 专用的 SDA pin
- 手柄黄线 (SCL) –> 模拟引脚 5 或者 专用的 SCL pin
连接伺服电机到Arduino

Servo 1 (x-axis)
舵机棕线 (GND) –> Arduino GND
舵机红线 (5V) –> Arduino 5V
舵机黄线 (data/Signal) –> Arduino Pin 10
Servo 2 (y-axis)
舵机棕线 (GND) –> Arduino GND
舵机红线 (5V) –> Arduino 5V
舵机黄线 (data/Signal) –> Arduino Pin 9

连接全部组件

代码部分
使用Arduino IDE上传代码前,需要两个标准库: Wire.h 、 Servo.h 。
代码的执行顺序如下:
- 初始化Nunchuk手柄的I2C接口;
- 初始化伺服系统 ;
- 读取Nunchuk手柄的数据;
- 根据读取得 Nunchuk 手柄的实时数据控制伺服电机运动。
完整代码如下:
/* * NunchuckPrint * 2007 Tod E. Kurt, http://todbot.com/blog/ * Change log: * * Mark Tashiro - Changed Wire.read to Wire.write * Changed Wire.receive to Wire.read * Added code for servos */ #include <Wire.h> #include <Servo.h> Servo servoLeft; // Define left servo Servo servoRight; // Define right servo static uint8_t nunchuck_buf[6]; // array to store nunchuck data, void setup() { Serial.begin(19200); servoLeft.attach(10); // Set left servo to digital pin 10 servoRight.attach(9); // Set right servo to digital pin 9 nunchuck_setpowerpins(); // use analog pins 2&3 as fake gnd & pwr nunchuck_init(); // send the initilization handshake Serial.print ("Finished setup\n"); } void loop() { nunchuck_get_data(); // map nunchuk data to a servo data point int x_axis = map(nunchuck_buf[0], 23, 222, 180, 0); int y_axis = map(nunchuck_buf[1], 32, 231, 0, 180); //move servo to desired position based on Wii nunchuk reading servoLeft.write(x_axis); servoRight.write(y_axis); // un-comment next line to print data to serial monitor // nunchuck_print_data(); } // // Nunchuck functions // // Uses port C (analog in) pins as power & ground for Nunchuck static void nunchuck_setpowerpins() { #define pwrpin PORTC3 #define gndpin PORTC2 DDRC |= _BV(pwrpin) | _BV(gndpin); PORTC &=~ _BV(gndpin); PORTC |= _BV(pwrpin); delay(100); // wait for things to stabilize } // initialize the I2C system, join the I2C bus, // and tell the nunchuck we're talking to it void nunchuck_init() { Wire.begin(); // join i2c bus as master Wire.beginTransmission(0x52); // transmit to device 0x52 Wire.write(0x40); // sends memory address Wire.write(0x00); // sends sent a zero. Wire.endTransmission(); // stop transmitting } // Send a request for data to the nunchuck // was "send_zero()" void nunchuck_send_request() { Wire.beginTransmission(0x52); // transmit to device 0x52 Wire.write(0x00); // sends one byte Wire.endTransmission(); // stop transmitting } // Receive data back from the nunchuck, int nunchuck_get_data() { int cnt=0; Wire.requestFrom (0x52, 6); // request data from nunchuck while (Wire.available ()) { // receive byte as an integer nunchuck_buf[cnt] = nunchuk_decode_byte(Wire.read()); cnt++; } nunchuck_send_request(); // send request for next data payload // If we recieved the 6 bytes, then go print them if (cnt >= 5) { return 1; // success } return 0; //failure } // 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 nunchuck_print_data() { static int i=0; int joy_x_axis = nunchuck_buf[0]; int joy_y_axis = nunchuck_buf[1]; int accel_x_axis = nunchuck_buf[2]; // * 2 * 2; int accel_y_axis = nunchuck_buf[3]; // * 2 * 2; int accel_z_axis = nunchuck_buf[4]; // * 2 * 2; int z_button = 0; int c_button = 0; // byte nunchuck_buf[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 ((nunchuck_buf[5] >> 0) & 1) z_button = 1; if ((nunchuck_buf[5] >> 1) & 1) c_button = 1; if ((nunchuck_buf[5] >> 2) & 1) accel_x_axis += 2; if ((nunchuck_buf[5] >> 3) & 1) accel_x_axis += 1; if ((nunchuck_buf[5] >> 4) & 1) accel_y_axis += 2; if ((nunchuck_buf[5] >> 5) & 1) accel_y_axis += 1; if ((nunchuck_buf[5] >> 6) & 1) accel_z_axis += 2; if ((nunchuck_buf[5] >> 7) & 1) accel_z_axis += 1; Serial.print(i,DEC); Serial.print("\t"); Serial.print("joy:"); Serial.print(joy_x_axis,DEC); Serial.print(","); Serial.print(joy_y_axis, DEC); Serial.print(" \t"); Serial.print("acc:"); Serial.print(accel_x_axis, DEC); Serial.print(","); Serial.print(accel_y_axis, DEC); Serial.print(","); Serial.print(accel_z_axis, DEC); Serial.print("\t"); Serial.print("but:"); Serial.print(z_button, DEC); Serial.print(","); Serial.print(c_button, DEC); Serial.print("\r\n"); // newline i++; } // 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; }