As seen in MotoGP Race, the rider is seen riding through corners while laying aside his bike to the left and right. But there is an interesting moment when the motor looks to collapse sideward, the front views remain horizontally. How could that be?
Such onboard camera applies GYRO system, where the camera will be fixed perpendicular to the gravity of the earth.

Step 1: BUILD YOUR OWN GYRO CAMERA

We could build our own Gyro Camera by using GYRO and ACCELEROMETER modules.
They are two separate modules, hence we have to use two modules simultaneously. Then we make Gyro Chip and Accelerometer Chip in one module (there are two chips in one module). In latest version they are made in one chip only, thus minimizing the distortion of movement calculation

In this article, the module is Triple Axis Accelerometer & Gyro Breakout – MPU-6050, which has 3-axis gyroscope and 3-axis accelerometer in one chip, supplied by power of 3.3volt.

In addition to module MPU6050, the following similar modules could also be applied:
• IMU Fusion Board – ADXL345 & IMU3000
• IMU Digital Combo Board – 6 Degrees of Freedom ITG3200/ADXL345

Module MPU6050 with its tiny size of 20mm x 15mm and height of 1.6mm.

The components are:
• Triple Axis Accelerometer & Gyro Breakout – MPU-6050
• Arduino UNO R3
• Digital Servo (use good and powerful servo)
• Breadboard Mini
• 9v Battery + Switch
• Box and other accessories.

If you using different board than Arduino Uno R3, SCL and SDA pins of MPU are also different:

VDD : +3.3V
VIO : +3.3V
GND : GND
SDA : Pin A4 (Arduino Uno, Ethernet) / Pin 20 (Mega2560, Due) / Pin 2 (Leonardo)
SCL : Pin A5 (Arduino Uno, Ethernet) / Pin 21 (Mega2560, Due) / Pin 3 (Leonardo)

Step 2: PROGRAMMING

After having completely assembled, it is time now to upload the program to Arduino.

This circuit is only to drive servo in axis-X only. However, data from Axis Y and Z are still required for the respective Gyroscope and Accelerometer. I tried to combine them by applying Kalman Filter calculation so as to reduce ‘noise’ output from Gyroscope + Accelerometer so that servo movement is smooth and no unwanted movement.

CODE:

/*
GYRO CAMERA - saft7.com

Demonstrates auto-leveling Camera Video by using Gyro & Accelerometer with Arduino

The circuit:
Servo controlled by Arduino, using Gyro and Accelerometer as reference of movement.

Created March 12, 2013
by Firmansyah Saftari
www.saft7.com

This code and complete article can be found at:

http://www.saft7.com/

Programming Language: C++

*/

#include <Servo.h>
Servo xservo;

#include <Wire.h>
#include "Kalman.h"
Kalman kalmanX;
Kalman kalmanY;

uint8_t IMUAddress = 0x68; // MPU6050 Address

/* IMU Data */
int16_t accX;
int16_t accY;
int16_t accZ;
int16_t tempRaw;
int16_t gyroX;
int16_t gyroY;
int16_t gyroZ;

int moveX;
int mapX;
int correctionX;

double accXangle;
double accYangle;
double gyroXangle = 9;
double gyroYangle = 180;
double compAngleX = 90;
double compAngleY = 90;
double kalAngleX;
double kalAngleY;
uint32_t timer;

// ---------- VOID SETUP START -------------- /
void setup() {
Serial.begin(115200);
xservo.attach(10);

Wire.begin();
i2cWrite(0x6B,0x00);           // Disable sleep mode
if(i2cRead(0x75,1)[0] != 0x68) {   // Read "WHO_AM_I" register
    Serial.print(F("MPU-6050 with address 0x"));
    Serial.print(IMUAddress,HEX);
    Serial.println(F(" is not connected"));
    while(1);
}
kalmanX.setAngle(90); // Set starting angle
kalmanY.setAngle(90);
timer = micros();
}

// ---------- VOID SETUP END -------------- /

// ---------------------- VOID LOOP START -------------- /
void loop() {
/* Update all the values */
uint8_t* data = i2cRead(0x3B,14);
accX = ((data[0] << 8) | data[1]);
accY = ((data[2] << 8) | data[3]);
accZ = ((data[4] << 8) | data[5]);
tempRaw = ((data[6] << 8) | data[7]);
gyroX = ((data[8] << 8) | data[9]);
gyroY = ((data[10] << 8) | data[11]);
gyroZ = ((data[12] << 8) | data[13]);

/* Calculate the angls based on the different sensors and algorithm */

accYangle = (atan2(accX,accZ)+PI)*RAD_TO_DEG;
accXangle = (atan2(accY,accZ)+PI)*RAD_TO_DEG;
double gyroXrate = (double)gyroX/131.0;
double gyroYrate = -((double)gyroY/131.0);
gyroXangle += gyroXrate*((double)(micros()-timer)/1000000); // Calculate gyro angle without any filter

gyroXangle += kalmanX.getRate()*((double)(micros()-timer)/1000000); // Calculate gyro angle using the unbiased rate
compAngleX = (0.93*(compAngleX+(gyroXrate*(double)(micros()-timer)/1000000)))+(0.07*accXangle); // Calculate the angle using a Complimentary filter

kalAngleX = kalmanX.getAngle(accXangle, gyroXrate, (double)(micros()-timer)/1000000); // Calculate the angle using a Kalman filter
timer = micros();
mapX = map(kalAngleX, 0, 200, 0, 179);     //calculate limitation of servo mechanical

// /////////////////////////////

    correctionX = 27;     // EDIT THIS VALUE FOR SERVO CORRECTION ANGLE

// ////////////////////////////

moveX = 270 - (kalAngleX) + correctionX;

// ------- SEND TO SERIAL PRINT START ----- /

Serial.print("saft7.com X Pos: ");
Serial.print(moveX);Serial.print("\t");
Serial.print("\n");

// ------- SEND TO SERIAL PRINT END ----- /

// ------- SEND TO SERVO START ----- /

   xservo.write(moveX);   // Send signal to servo
   delay(15);     // delay to allow servos to move (ms)

// ------- SEND TO SERVO END ----- /

delay(1); // The accelerometer's maximum samples rate is 1kHz
}
// ---------------------- VOID LOOP END -------------- /

// -- FUNCTIONS START --
void i2cWrite(uint8_t registerAddress, uint8_t data){
Wire.beginTransmission(IMUAddress);
Wire.write(registerAddress);
Wire.write(data);
Wire.endTransmission();                       // Send stop
}

uint8_t* i2cRead(uint8_t registerAddress, uint8_t nbytes) {
uint8_t data[nbytes];
Wire.beginTransmission(IMUAddress);
Wire.write(registerAddress);
Wire.endTransmission(false); // Don't release the bus
Wire.requestFrom(IMUAddress, nbytes);   // Send a repeated start and then release the bus after reading
for(uint8_t i = 0; i < nbytes; i++)
    data[i] = Wire.read();
return data;
}
// -- FUNCTIONS END --

// GYROCAM BY SAFT7.COM //

// END

Step 3: Build the Camera Bracket

I use 2 mm Acrylic 2mm, bent by heating. Make the necessary holes for servo installation and for the camera bolt.

Camera bolt was taken from an unused small tripod so as to ease the camera installation.

Arduino Board is installed onto the box plate.

Arduino, Servo and MPU6050 have been installed on the box.

Video of Servo testing on box

Video on the testing of installed camera

Step 4: TIME TO TRY

Camera is placed on motorcycle.

Let’s ride to try …

Lessons Learned:
• Gyro + accelerometer modules should be installed firmly.
• Calibration of horizontal level should be on flat area
• Use powerful servo.
• Use heavy duty battery so hat power to servo is well supplied.

Good luck.

Saftari

Translated by Taufik Masjhur

This post was originally published on saft7.com in Bahasa Indonesia language.