The modified version of my mpu6050 balancing robot more stable with LCD and example of connect 2 i2c on the same pin

video 1

video 2

Step 1: Step 1 : ◾L298N Dual Motor Driver Breakout Board

◾L298N dual motor driver breakout board

12 V BATTARY
9 V BATTARY
geared DC motors x 2
The robot is made out of lego

•Motor Voltage: 12

v•SPEED: 122r/min

•Diameter: 25 mm

•Output shaft:10 mm

•Weight: 90g

•L length: 55 mm

•Wheels Diameter: 65mm

Step 2: Step 2 : ◾Arduino Uno

using lego and arduino
◾Arduino Uno
◾Invensense MPU-6050 IMU

SDA - ANALOG Pin 4
SCL - ANALOG pin 5

The IMU is connected to the arduino using I2C bus
u should connect the lcd on the same bus
u add resistance to put 2 devices on the same bus
The motor driver take power directly form the battery so don't have to connect arduino's power to it (i mean the 5V form the arduino), but we need 6 wires to control it, 3 for each motor, one for send the PWM signal for control the motor velocity, and for indicate the direction we want the motor to spin.

Step 3: Step 3 : LCD Display

LCD display

Example Software Sketch for 4 line 20 character Displays:
(NOTE: for displays with backpack interface labelled "YwRobot Arduino LCM1602 IIC V1")
Top to bottom:
GND - GND
VCC - 5V
SDA - ANALOG Pin 4
SCL - ANALOG pin 5
On most Arduino boards, SDA (data line) is on analog input pin 4, and SCL (clock line) is on analog input pin 5. On the Arduino Mega, SDA is digital pin 20 and SCL is 21.
NOTE: The Blue Potentiometer (Photo) adjusts Contrast. If you don't see any characters, adjust it. Start clockwise and back down to where the characters are bright and the background does not have boxes behind the characters.

Step 4: Step 4 : the Code

I upload the code on the attach File

#include

#include
#include "I2Cdev.h"
#include "MPU6050_6Axis_MotionApps20.h"
#include
//lcd
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);

#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
#include "Wire.h"
#endif

#define LOG_INPUT 0
#define MANUAL_TUNING 0
#define LOG_PID_CONSTANTS 1 //MANUAL_TUNING must be 1
#define MOVE_BACK_FORTH 0
#define MIN_ABS_SPEED 30
//MPU

MPU6050 mpu;
// MPU control/status vars
bool dmpReady = false; // set true if DMP init was successful
uint8_t mpuIntStatus; // holds actual interrupt status byte from MPU
uint8_t devStatus; // return status after each device operation (0 = success, !0 = error)
uint16_t packetSize; // expected DMP packet size (default is 42 bytes)
uint16_t fifoCount; // count of all bytes currently in FIFO
uint8_t fifoBuffer[64]; // FIFO storage buffer
// orientation/motion vars
Quaternion q; // [w, x, y, z] quaternion container
VectorFloat gravity; // [x, y, z] gravity vector
float ypr[3]; // [yaw, pitch, roll] yaw/pitch/roll container and gravity vector

//PID

#if MANUAL_TUNING
double kp , ki, kd;
double prevKp, prevKi, prevKd;
#endif
double originalSetpoint = 174.29;
double setpoint = originalSetpoint;
double movingAngleOffset = 0.3;
double input, output;
int moveState=0; //0 = balance; 1 = back; 2 = forth
int LED = 13;
int LED2 = 10;
#if MANUAL_TUNING
PID pid(&input, &output, &setpoint, 0, 0, 0, DIRECT);
#else
PID pid(&input, &output, &setpoint, 230, 300, 2.9, DIRECT);
#endif

//MOTOR CONTROLLER

int ENA = 3;
int IN1 = 4;
int IN2 = 8;
int IN3 = 5;
int IN4 = 7;
int ENB = 6;

LMotorController motorController(ENA, IN1, IN2, ENB, IN3, IN4, 0.6, 1);

//timers

long time1Hz = 0;
long time5Hz = 0;

volatile bool mpuInterrupt = false; // indicates whether MPU interrupt pin has gone high
void dmpDataReady()
{
mpuInterrupt = true;
}

void setup()
{
// join I2C bus (I2Cdev library doesn't do this automatically)
#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
Wire.begin();
TWBR = 24; // 400kHz I2C clock (200kHz if CPU is 8MHz)
#elif I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_FASTWIRE
Fastwire::setup(200, true);
#endif
pinMode(LED,OUTPUT);
digitalWrite(LED,HIGH);
//pinMode(LED2,OUTPUT);
//digitalWrite(LED2,HIGH);
// initialize serial communication
// (115200 chosen because it is required for Teapot Demo output, but it's
// really up to you depending on your project)
Serial.begin(115200);

lcd.begin(20,4); // initialize the lcd for 20 chars 4 lines and turn on backlight
// ------- Quick 3 blinks of backlight -------------
for(int i = 0; i< 4; i++)
{
lcd.backlight();
delay(250);
lcd.noBacklight();
delay(250);
}
lcd.backlight(); // finish with backlight on

//-------- Write characters on the display ----------------
// NOTE: Cursor Position: CHAR, LINE) start at 0
lcd.setCursor(3,0); //Start at character 4 on line 0
lcd.print("Hello, world!!!!");
delay(1000);
lcd.setCursor(2,1);
lcd.print("My name KHALID");
delay(1000);
lcd.setCursor(0,2);
lcd.print("Self Balancing ROBOT");
lcd.setCursor(0,3);
delay(700);
lcd.print("youtube:CAYMANGUY123");
delay(2000);

while (!Serial); // wait for Leonardo enumeration, others continue immediately
// initialize device
Serial.println(F("Initializing I2C devices..."));
lcd.setCursor(0,0); //Start at character 4 on line 0
lcd.print(F("Initializing I2C"));
delay(1000);
mpu.initialize();
// verify connection
Serial.println(F("Testing device connections..."));
lcd.setCursor(0,1); //Start at character 4 on line 0
lcd.print(F("Testing devices "));
delay(1000);
Serial.println(mpu.testConnection() ? F("MPU6050 connection successful") : F("MPU6050 connection failed"));
lcd.setCursor(0,3);
lcd.println(mpu.testConnection() ? F("MPU6050 connection") : F("MPU6050 connection failed"));
// load and configure the DMP
Serial.println(F("Initializing DMP..."));

devStatus = mpu.dmpInitialize();
// supply your own gyro offsets here, scaled for min sensitivity
mpu.setXGyroOffset(220);
mpu.setYGyroOffset(98);
mpu.setZGyroOffset(-85);
mpu.setZAccelOffset(1788); // 1688 factory default for my test chip
// make sure it worked (returns 0 if so)
if (devStatus == 0)
{
// turn on the DMP, now that it's ready
Serial.println(F("Enabling DMP..."));

mpu.setDMPEnabled(true);
// enable Arduino interrupt detection
Serial.println(F("Enabling interrupt detection (Arduino external interrupt 0)..."));
attachInterrupt(0, dmpDataReady, RISING);
mpuIntStatus = mpu.getIntStatus();
// set our DMP Ready flag so the main loop() function knows it's okay to use it
Serial.println(F("DMP ready! Waiting for first interrupt..."));
dmpReady = true;
// get expected DMP packet size for later comparison
packetSize = mpu.dmpGetFIFOPacketSize();

//setup PID

pid.SetMode(AUTOMATIC);
pid.SetSampleTime(10);
pid.SetOutputLimits(-255, 255);
}
else
{
// ERROR!
// 1 = initial memory load failed
// 2 = DMP configuration updates failed
// (if it's going to break, usually the code will be 1)
Serial.print(F("DMP Initialization failed (code "));
Serial.print(devStatus);
Serial.println(F(")"));
}
}

void loop()
{
// if programming failed, don't try to do anything
if (!dmpReady) return;
// wait for MPU interrupt or extra packet(s) available
while (!mpuInterrupt && fifoCount < packetSize)
{
//no mpu data - performing PID calculations and output to motors

pid.Compute();
motorController.move(output, MIN_ABS_SPEED);

unsigned long currentMillis = millis();
if (currentMillis - time1Hz >= 1000)
{
loopAt1Hz();
time1Hz = currentMillis;
}

if (currentMillis - time5Hz >= 5000)
{
loopAt5Hz();
time5Hz = currentMillis;
}
}
// reset interrupt flag and get INT_STATUS byte
mpuInterrupt = false;
mpuIntStatus = mpu.getIntStatus();
// get current FIFO count
fifoCount = mpu.getFIFOCount();
// check for overflow (this should never happen unless our code is too inefficient)
if ((mpuIntStatus & 0x10) || fifoCount == 1024)
{
// reset so we can continue cleanly
mpu.resetFIFO();
Serial.println(F("FIFO overflow!"));

// otherwise, check for DMP data ready interrupt (this should happen frequently)
}
else if (mpuIntStatus & 0x02)
{
// wait for correct available data length, should be a VERY short wait
while (fifoCount < packetSize) fifoCount = mpu.getFIFOCount();
// read a packet from FIFO
mpu.getFIFOBytes(fifoBuffer, packetSize);

// track FIFO count here in case there is > 1 packet available
// (this lets us immediately read more without waiting for an interrupt)
fifoCount -= packetSize;
mpu.dmpGetQuaternion(&q, fifoBuffer);
mpu.dmpGetGravity(&gravity, &q);
mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
#if LOG_INPUT
Serial.print("ypr\t");
Serial.print(ypr[0] * 180/M_PI);
Serial.print("\t");
Serial.print(ypr[1] * 180/M_PI);
Serial.print("\t");
Serial.println(ypr[2] * 180/M_PI);

#endif
input = ypr[1] * 180/M_PI + 180;
}
}

void loopAt1Hz()
{
#if MANUAL_TUNING
setPIDTuningValues();
#endif
}

void loopAt5Hz()
{
#if MOVE_BACK_FORTH
moveBackForth();
#endif
}

//move back and forth

void moveBackForth()
{
moveState++;
if (moveState > 2) moveState = 0;

if (moveState == 0)
setpoint = originalSetpoint;
else if (moveState == 1)
setpoint = originalSetpoint - movingAngleOffset;
else
setpoint = originalSetpoint + movingAngleOffset;

}

//PID Tuning (3 potentiometers)
#if MANUAL_TUNING
void setPIDTuningValues()
{
readPIDTuningValues();

if (kp != prevKp || ki != prevKi || kd != prevKd)
{
#if LOG_PID_CONSTANTS
Serial.print(kp);Serial.print(", ");Serial.print(ki);Serial.print(", ");Serial.println(kd);
#endif
pid.SetTunings(kp, ki, kd);
prevKp = kp; prevKi = ki; prevKd = kd;
}
}

void readPIDTuningValues()
{
int potKp = analogRead(A0);
int potKi = analogRead(A1);
int potKd = analogRead(A2);

kp = map(potKp, 0, 1023, 0, 25000) / 100.0; //0 - 250
ki = map(potKi, 0, 1023, 0, 100000) / 100.0; //0 - 1000
kd = map(potKd, 0, 1023, 0, 500) / 100.0; //0 - 5
}
#endif

Step 5: Improvements :

There are some much improvements to do with this robot, this is the first step of many more:
1.The first i want to implement is the position recovery
3.Adding a Wi-Fi shield to control it via internet.
4.Implementation with Raspberry Pi to allow the robot to use a camera.
5.Implementation of a camera and artificial vision for the robot.
6.Use a ball instead of wheels, so hard, but we'll try.
7.add a Bluetooth controller
8.or IR remote control like my first robot with IR