The document describes using an Arduino Micro to read acceleration and gyroscope values from an MPU-6050 sensor module over I2C. It connects the sensor to the Arduino, initializes the sensor library, sets the sensor ranges, and reads the signed 16-bit acceleration and rotation values. It transmits the sensor ID and acceleration/gyroscope values over serial to an openFrameworks application, which splits the received string into numbers and draws a rectangle representing the acceleration value.

1. Switch_lecture
FullColorLED & MPU-6050

2. FullColorLED
ArduinoMicro
5V
10 (PWM)
11 (PWM)
Common
9 (PWM) Red
Green
Blue
OSTA71A1D-A
Anode→
Cathode←150Ω
100Ω
100Ω
Cathode←
Cathode←

3. Arduino sketch
Set pin mode OUTPUT
Declare LED pins
Set LED color Red
Set LED function
0 -> HIGH
255 -> LOW
(Anode Common)
const int ledPins[] = { 9, 10, 11 };
const int nLedPins = 3;
void setup()
{
for( int i = 0; i < nLedPins; ++i )
{
pinMode( ledPins[ i ], OUTPUT );
}
setLed( 255, 0, 0 );
}
void loop()
{
}
void setLed( int _r, int _g, int _b )
{
analogWrite( ledPins[ 0 ], 255 - _r );
analogWrite( ledPins[ 1 ], 255 - _g );
analogWrite( ledPins[ 2 ], 255 - _b );
}

4. MPU-6050(GY-521)
( I2C Interface )
ArduinoMicro
5V
GND
3 (SCL)
2 (SDA)
VCC
GND
SCL
SDA
MPU-6050

5. Arduino Library
Download “i2cdevlib” from
github.com/jrowberg/i2cdevlib
into “書類 / Arduino / Libraries /”
i2cdevlib / Arduino / I2Cdev and
Copy
Paste
i2cdevlib / Arduino / MPU6050

6. Example
Arduino / Libraries / MPU6050 / Examples / MPU6050_raw / MPU6050_raw.ino
raw データを取得する Example
ここから不要な部分を削っていく。

7. Arduino sketch
MPU6050 object
Include libraries
Sensor values
Initialize
Set full scale accel range 16G
Set full scale gyro range 2000dps
Get acceleration values
Get rotation values
#include "I2Cdev.h"
#include "MPU6050.h"
#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
#include "Wire.h"
#endif
MPU6050 accelgyro;
int16_t ax, ay, az;
int16_t gx, gy, gz;
int id = 0;
void setup()
{
#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
Wire.begin();
#elif I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_FASTWIRE
Fastwire::setup( 400, true );
#endif
Serial1.begin( 9600 );
accelgyro.initialize();
accelgyro.setFullScaleAccelRange( MPU6050_ACCEL_FS_16 );
accelgyro.setFullScaleGyroRange( MPU6050_GYRO_FS_2000 );
}
void loop()
{
accelgyro.getAcceleration( &ax, &ay, &az );
accelgyro.getRotation( &gx, &gy, &gz );
Serial1.print( id );
Serial1.print( "," );
Serial1.print( ax );
Serial1.print( "," );
Serial1.print( gz );
Serial1.println();
delay( 60 );
}
( ArduinoMicro + XBee + MPU-6050 )

8. Arduino sketch
int16_t = -32768 ~ 32767
accelgyro.initialize()
accelgyro.setFullScaleAccelRange( MPU6050_ACCEL_FS_16 )
accelgyro.setFullScaleGyroRange( MPU6050_GYRO_FS_2000 )
signed 16bit
この中で
されている
setFullScaleAccelRange( MPU6050_ACCEL_FS_2 )
setFullScaleGyroRange( MPU6050_GYRO_FS_250 )
( ArduinoMicro + XBee + MPU-6050 )
250dps 2000dps
Accel
2G 16G
Gyro

9. Arduino sketch
( ArduinoMicro + XBee + MPU-6050 )
Address of “ax”
Memory
Address 0x00
ax
&ax
int16_t
x
int16_t*
0x01 0x02 0x03 0x04
...
“MPU6050.h”
accelgyro.getAcceleration( &ax, &ay, &az )
void MPU6050::getAcceleration( int16_t* x, int16_t* y, int16_t* z )
Pointer of “int16_t”
int16_t* x = &ax;
assign address to pointer
Memory
Address 0x00
ax
*x
x
int16_t
x
int16_t*
0x01 0x02 0x03 0x04
...
*x = -32768; ax = -32768;
in automatically
ax -32768

10. Read Serial
( openFrameworks )
ofApp.h ofApp.cpp
class ofApp : public ofBaseApp
{
public:
ofSerial serial;
string str;
int index, ax, gz;
};
void ofApp::setup()
{
index = ax = gz = 0;
str = "";
serial.listDevices();
serial.setup( 0, 9600 );
ofBackground( 255 );
}
void ofApp::update()
{
while( true )
{
int c = serial.readByte();
if( c == OF_SERIAL_NO_DATA || c == OF_SERIAL_ERROR || c == 0 )
{
break;
}
if( c == ‘n’ )
{
vector< string > valStr = ofSplitString( str, "," );
if( valStr.size() == 3 )
{
index = ofToInt( valStr.at( 0 ) );
ax = abs( ofToInt( valStr.at( 1 ) ) );
gz = ofToInt( valStr.at( 2 ) );
}
str = "";
}
else
{
str.push_back( c );
}
}
}

11. Flow Chart
false
read 1 character
false
true
true
int c = serial.readByte()
c == OF_SERIAL_NO_DATA
or
c == OF_SERIAL_ERROR
or
c == 0
while( true )
break str.push_back( c )
c == ‘n’
ofSplitString( str, "," )
str = ""
index = ofToInt( valStr.at( 0 ) )
ax = abs( ofToInt( valStr.at( 1 ) ) )
gz = ofToInt( valStr.at( 2 ) )

12. Get values from string
“0,-32768,32767”
convert to int from string
index = ofToInt( valStr.at( 0 ) )
ax = abs( ofToInt( valStr.at( 1 ) ) )
gz = ofToInt( valStr.at( 2 ) )
“0” “-32768” “32767”
id
string
string
ax gz
string
int
vector< string > valStr = ofSplitString( str, "," )
-32768 ~ 32767 0 ~ 32768

13. Draw with sensor value
x = 0 ~ 32768
( float )x / 32768 = 0.0 ~ 1.0
( ( float )x / 32768 ) * ofGetWidth() = 0.0 ~ ofGetWidth()
( openFrameworks )
necessary to re-scale values
ofApp.cpp
void ofApp::draw()
{
ofSetColor( 0 );
ofFill();
ofRect( 0, 0, ( ( float )ax / 32768 ) * ofGetWidth(), 60 );
}