Simple 2-axis Servo Robotic Arm controlled by MPU-6050

1// I2C device class (I2Cdev) demonstration Arduino sketch for MPU6050  class using DMP (MotionApps v2.0)
2// 6/21/2012 by Jeff Rowberg <jeff@rowberg.net>
3//  Updates should (hopefully) always be available at https://github.com/jrowberg/i2cdevlib
4//
5//  Changelog:
6//      2013-05-08 - added seamless Fastwire support
7//                 -  added note about gyro calibration
8//      2012-06-21 - added note about Arduino  1.0.1 + Leonardo compatibility error
9//      2012-06-20 - improved FIFO overflow  handling and simplified read process
10//      2012-06-19 - completely rearranged  DMP initialization code and simplification
11//      2012-06-13 - pull gyro and  accel data from FIFO packet instead of reading directly
12//      2012-06-09 -  fix broken FIFO read sequence and change interrupt detection to RISING
13//      2012-06-05  - add gravity-compensated initial reference frame acceleration output
14//                 -  add 3D math helper file to DMP6 example sketch
15//                 - add Euler  output and Yaw/Pitch/Roll output formats
16//      2012-06-04 - remove accel offset  clearing for better results (thanks Sungon Lee)
17//      2012-06-01 - fixed gyro  sensitivity to be 2000 deg/sec instead of 250
18//      2012-05-30 - basic DMP  initialization working
19
20/* ============================================
21I2Cdev  device library code is placed under the MIT license
22Copyright (c) 2012 Jeff Rowberg
23
24Permission  is hereby granted, free of charge, to any person obtaining a copy
25of this software  and associated documentation files (the "Software"), to deal
26in the Software  without restriction, including without limitation the rights
27to use, copy, modify,  merge, publish, distribute, sublicense, and/or sell
28copies of the Software, and  to permit persons to whom the Software is
29furnished to do so, subject to the  following conditions:
30
31The above copyright notice and this permission notice  shall be included in
32all copies or substantial portions of the Software.
33
34THE  SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
35IMPLIED,  INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
36FITNESS FOR A  PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
37AUTHORS OR COPYRIGHT  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
38LIABILITY, WHETHER IN AN ACTION  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
39OUT OF OR IN CONNECTION WITH THE  SOFTWARE OR THE USE OR OTHER DEALINGS IN
40THE SOFTWARE.
41===============================================
42*/
43
44//  I2Cdev and MPU6050 must be installed as libraries, or else the .cpp/.h files
45//  for both classes must be in the include path of your project
46#include "I2Cdev.h"
47
48#include  "MPU6050_6Axis_MotionApps20.h"
49//#include "MPU6050.h" // not necessary if  using MotionApps include file
50
51// Arduino Wire library is required if I2Cdev  I2CDEV_ARDUINO_WIRE implementation
52// is used in I2Cdev.h
53#if I2CDEV_IMPLEMENTATION  == I2CDEV_ARDUINO_WIRE
54    #include "Wire.h"
55#endif
56
57// class default  I2C address is 0x68
58// specific I2C addresses may be passed as a parameter here
59//  AD0 low = 0x68 (default for SparkFun breakout and InvenSense evaluation board)
60//  AD0 high = 0x69
61MPU6050 mpu;
62//MPU6050 mpu(0x69); // <-- use for AD0 high
63
64/*  =========================================================================
65   NOTE:  In addition to connection 3.3v, GND, SDA, and SCL, this sketch
66   depends on  the MPU-6050's INT pin being connected to the Arduino's
67   external interrupt  #0 pin. On the Arduino Uno and Mega 2560, this is
68   digital I/O pin 2.
69 *  ========================================================================= */
70
71/*  =========================================================================
72   NOTE:  Arduino v1.0.1 with the Leonardo board generates a compile error
73   when using  Serial.write(buf, len). The Teapot output uses this method.
74   The solution requires  a modification to the Arduino USBAPI.h file, which
75   is fortunately simple,  but annoying. This will be fixed in the next IDE
76   release. For more info, see  these links:
77
78   http://arduino.cc/forum/index.php/topic,109987.0.html
79   http://code.google.com/p/arduino/issues/detail?id=958
80 * =========================================================================  */
81
82
83
84// uncomment "OUTPUT_READABLE_QUATERNION" if you want to see  the actual
85// quaternion components in a [w, x, y, z] format (not best for parsing
86//  on a remote host such as Processing or something though)
87//#define OUTPUT_READABLE_QUATERNION
88
89//  uncomment "OUTPUT_READABLE_EULER" if you want to see Euler angles
90// (in degrees)  calculated from the quaternions coming from the FIFO.
91// Note that Euler angles  suffer from gimbal lock (for more info, see
92// http://en.wikipedia.org/wiki/Gimbal_lock)
93//#define  OUTPUT_READABLE_EULER
94
95// uncomment "OUTPUT_READABLE_YAWPITCHROLL" if you  want to see the yaw/
96// pitch/roll angles (in degrees) calculated from the quaternions  coming
97// from the FIFO. Note this also requires gravity vector calculations.
98//  Also note that yaw/pitch/roll angles suffer from gimbal lock (for
99// more info,  see: http://en.wikipedia.org/wiki/Gimbal_lock)
100#define OUTPUT_READABLE_YAWPITCHROLL
101
102//  uncomment "OUTPUT_READABLE_REALACCEL" if you want to see acceleration
103// components  with gravity removed. This acceleration reference frame is
104// not compensated  for orientation, so +X is always +X according to the
105// sensor, just without  the effects of gravity. If you want acceleration
106// compensated for orientation,  us OUTPUT_READABLE_WORLDACCEL instead.
107//#define OUTPUT_READABLE_REALACCEL
108
109//  uncomment "OUTPUT_READABLE_WORLDACCEL" if you want to see acceleration
110// components  with gravity removed and adjusted for the world frame of
111// reference (yaw is  relative to initial orientation, since no magnetometer
112// is present in this  case). Could be quite handy in some cases.
113//#define OUTPUT_READABLE_WORLDACCEL
114
115//  uncomment "OUTPUT_TEAPOT" if you want output that matches the
116// format used  for the InvenSense teapot demo
117//#define OUTPUT_TEAPOT
118
119
120
121#define  LED_PIN 13 // (Arduino is 13, Teensy is 11, Teensy++ is 6)
122bool blinkState =  false;
123
124// MPU control/status vars
125bool dmpReady = false;  // set true  if DMP init was successful
126uint8_t mpuIntStatus;   // holds actual interrupt  status byte from MPU
127uint8_t devStatus;      // return status after each device  operation (0 = success, !0 = error)
128uint16_t packetSize;    // expected DMP packet  size (default is 42 bytes)
129uint16_t fifoCount;     // count of all bytes currently  in FIFO
130uint8_t fifoBuffer[64]; // FIFO storage buffer
131
132// orientation/motion  vars
133Quaternion q;           // [w, x, y, z]         quaternion container
134VectorInt16  aa;         // [x, y, z]            accel sensor measurements
135VectorInt16 aaReal;     // [x, y, z]            gravity-free accel sensor measurements
136VectorInt16  aaWorld;    // [x, y, z]            world-frame accel sensor measurements
137VectorFloat  gravity;    // [x, y, z]            gravity vector
138float euler[3];         //  [psi, theta, phi]    Euler angle container
139float ypr[3];           // [yaw, pitch,  roll]   yaw/pitch/roll container and gravity vector
140
141// packet structure for  InvenSense teapot demo
142uint8_t teapotPacket[14] = { '$', 0x02, 0,0, 0,0, 0,0,  0,0, 0x00, 0x00, '\r', '\n' };
143
144
145
146// ================================================================
147//  ===               INTERRUPT DETECTION ROUTINE                ===
148// ================================================================
149
150volatile  bool mpuInterrupt = false;     // indicates whether MPU interrupt pin has gone high
151void  dmpDataReady() {
152    mpuInterrupt = true;
153}
154
155
156
157// ================================================================
158//  ===                      INITIAL SETUP                       ===
159// ================================================================
160
161void  setup() {
162    // join I2C bus (I2Cdev library doesn't do this automatically)
163    #if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
164        Wire.begin();
165        TWBR = 24; // 400kHz I2C clock (200kHz if CPU is 8MHz)
166    #elif I2CDEV_IMPLEMENTATION  == I2CDEV_BUILTIN_FASTWIRE
167        Fastwire::setup(400, true);
168    #endif
169
170    // initialize serial communication
171    // (115200 chosen because it is required  for Teapot Demo output, but it's
172    // really up to you depending on your project)
173    Serial.begin(115200);
174    while (!Serial); // wait for Leonardo enumeration,  others continue immediately
175
176    // NOTE: 8MHz or slower host processors,  like the Teensy @ 3.3v or Ardunio
177    // Pro Mini running at 3.3v, cannot handle  this baud rate reliably due to
178    // the baud timing being too misaligned with  processor ticks. You must use
179    // 38400 or slower in these cases, or use some  kind of external separate
180    // crystal solution for the UART timer.
181
182    // initialize device
183    Serial.println(F("Initializing I2C devices..."));
184    mpu.initialize();
185
186    // verify connection
187    Serial.println(F("Testing  device connections..."));
188    Serial.println(mpu.testConnection() ? F("MPU6050  connection successful") : F("MPU6050 connection failed"));
189
190    // wait  for ready
191    Serial.println(F("\
192Send any character to begin DMP programming  and demo: "));
193    while (Serial.available() && Serial.read()); // empty buffer
194    while (!Serial.available());                 // wait for data
195    while (Serial.available()  && Serial.read()); // empty buffer again
196
197    // load and configure the DMP
198    Serial.println(F("Initializing DMP..."));
199    devStatus = mpu.dmpInitialize();
200
201    // supply your own gyro offsets here, scaled for min sensitivity
202    mpu.setXGyroOffset(220);
203    mpu.setYGyroOffset(76);
204    mpu.setZGyroOffset(-85);
205    mpu.setZAccelOffset(1788);  // 1688 factory default for my test chip
206
207    // make sure it worked (returns  0 if so)
208    if (devStatus == 0) {
209        // turn on the DMP, now that it's  ready
210        Serial.println(F("Enabling DMP..."));
211        mpu.setDMPEnabled(true);
212
213        // enable Arduino interrupt detection
214        Serial.println(F("Enabling  interrupt detection (Arduino external interrupt 0)..."));
215        attachInterrupt(0,  dmpDataReady, RISING);
216        mpuIntStatus = mpu.getIntStatus();
217
218        //  set our DMP Ready flag so the main loop() function knows it's okay to use it
219        Serial.println(F("DMP ready! Waiting for first interrupt..."));
220        dmpReady  = true;
221
222        // get expected DMP packet size for later comparison
223        packetSize = mpu.dmpGetFIFOPacketSize();
224    } else {
225        // ERROR!
226        // 1 = initial memory load failed
227        // 2 = DMP configuration updates  failed
228        // (if it's going to break, usually the code will be 1)
229        Serial.print(F("DMP  Initialization failed (code "));
230        Serial.print(devStatus);
231        Serial.println(F(")"));
232    }
233
234    // configure LED for output
235    pinMode(LED_PIN, OUTPUT);
236}
237
238
239
240//  ================================================================
241// ===                    MAIN  PROGRAM LOOP                     ===
242// ================================================================
243
244void  loop() {
245    // if programming failed, don't try to do anything
246    if (!dmpReady)  return;
247
248    // wait for MPU interrupt or extra packet(s) available
249    while  (!mpuInterrupt && fifoCount < packetSize) {
250        // other program behavior  stuff here
251        // .
252        // .
253        // .
254        // if you  are really paranoid you can frequently test in between other
255        // stuff  to see if mpuInterrupt is true, and if so, "break;" from the
256        // while()  loop to immediately process the MPU data
257        // .
258        // .
259        //  .
260    }
261
262    // reset interrupt flag and get INT_STATUS byte
263    mpuInterrupt  = false;
264    mpuIntStatus = mpu.getIntStatus();
265
266    // get current FIFO  count
267    fifoCount = mpu.getFIFOCount();
268
269    // check for overflow (this  should never happen unless our code is too inefficient)
270    if ((mpuIntStatus  & 0x10) || fifoCount == 1024) {
271        // reset so we can continue cleanly
272        mpu.resetFIFO();
273        Serial.println(F("FIFO overflow!"));
274
275    // otherwise, check for DMP data ready interrupt (this should happen frequently)
276    } else if (mpuIntStatus & 0x02) {
277        // wait for correct available data  length, should be a VERY short wait
278        while (fifoCount < packetSize) fifoCount  = mpu.getFIFOCount();
279
280        // read a packet from FIFO
281        mpu.getFIFOBytes(fifoBuffer,  packetSize);
282        
283        // track FIFO count here in case there is >  1 packet available
284        // (this lets us immediately read more without waiting  for an interrupt)
285        fifoCount -= packetSize;
286
287        #ifdef OUTPUT_READABLE_QUATERNION
288            // display quaternion values in easy matrix form: w x y z
289            mpu.dmpGetQuaternion(&q,  fifoBuffer);
290            Serial.print("quat\	");
291            Serial.print(q.w);
292            Serial.print("\	");
293            Serial.print(q.x);
294            Serial.print("\	");
295            Serial.print(q.y);
296            Serial.print("\	");
297            Serial.println(q.z);
298        #endif
299
300        #ifdef OUTPUT_READABLE_EULER
301            // display  Euler angles in degrees
302            mpu.dmpGetQuaternion(&q, fifoBuffer);
303            mpu.dmpGetEuler(euler, &q);
304            Serial.print("euler\	");
305            Serial.print(euler[0] * 180/M_PI);
306            Serial.print("\	");
307            Serial.print(euler[1] * 180/M_PI);
308            Serial.print("\	");
309            Serial.println(euler[2] * 180/M_PI);
310        #endif
311
312        #ifdef  OUTPUT_READABLE_YAWPITCHROLL
313            // display Euler angles in degrees
314            mpu.dmpGetQuaternion(&q, fifoBuffer);
315            mpu.dmpGetGravity(&gravity,  &q);
316            mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
317            Serial.print("ypr\	");
318            Serial.print(ypr[0] * 180/M_PI);
319            Serial.print("\	");
320            Serial.print(ypr[1] * 180/M_PI);
321            Serial.print("\	");
322            Serial.println(ypr[2] * 180/M_PI);
323        #endif
324
325        #ifdef  OUTPUT_READABLE_REALACCEL
326            // display real acceleration, adjusted  to remove gravity
327            mpu.dmpGetQuaternion(&q, fifoBuffer);
328            mpu.dmpGetAccel(&aa,  fifoBuffer);
329            mpu.dmpGetGravity(&gravity, &q);
330            mpu.dmpGetLinearAccel(&aaReal,  &aa, &gravity);
331            Serial.print("areal\	");
332            Serial.print(aaReal.x);
333            Serial.print("\	");
334            Serial.print(aaReal.y);
335            Serial.print("\	");
336            Serial.println(aaReal.z);
337        #endif
338
339        #ifdef OUTPUT_READABLE_WORLDACCEL
340            // display initial world-frame acceleration, adjusted to remove gravity
341            // and rotated based on known orientation from quaternion
342            mpu.dmpGetQuaternion(&q,  fifoBuffer);
343            mpu.dmpGetAccel(&aa, fifoBuffer);
344            mpu.dmpGetGravity(&gravity,  &q);
345            mpu.dmpGetLinearAccel(&aaReal, &aa, &gravity);
346            mpu.dmpGetLinearAccelInWorld(&aaWorld,  &aaReal, &q);
347            Serial.print("aworld\	");
348            Serial.print(aaWorld.x);
349            Serial.print("\	");
350            Serial.print(aaWorld.y);
351            Serial.print("\	");
352            Serial.println(aaWorld.z);
353        #endif
354    
355        #ifdef  OUTPUT_TEAPOT
356            // display quaternion values in InvenSense Teapot demo  format:
357            teapotPacket[2] = fifoBuffer[0];
358            teapotPacket[3]  = fifoBuffer[1];
359            teapotPacket[4] = fifoBuffer[4];
360            teapotPacket[5]  = fifoBuffer[5];
361            teapotPacket[6] = fifoBuffer[8];
362            teapotPacket[7]  = fifoBuffer[9];
363            teapotPacket[8] = fifoBuffer[12];
364            teapotPacket[9]  = fifoBuffer[13];
365            Serial.write(teapotPacket, 14);
366            teapotPacket[11]++;  // packetCount, loops at 0xFF on purpose
367        #endif
368
369        // blink  LED to indicate activity
370        blinkState = !blinkState;
371        digitalWrite(LED_PIN,  blinkState);
372    }
373}