Moving the center of rotation of gyros on a mpu 605

Projects Programming
1

i while ago i modded a ps5 controller so that i could output potentiometer values from a arduino and digi pot to the solder points on the ps5 controller and output switches from the arduino to buttons on the controller.

this basically gives me a controller that i can change analog stick settings on and have remappable buttons on the back of the controller.

recently i added a mpu 6050 from a old gyro mouse project i made years ago, after deciding i would use the controller more than i have, or ever will use the gyro mouse. I use the mpu 6050 to output a gyro mouse to pc or to emulate a gyro mouse on a ps5.

i have coded the gyro aim so that 1 360 degree rotation of the controller makes the in game character rotate 360 degrees.

the problem is that because i didnt think of adding a gyro chip when first modding the controller there is only room for the mpu 6050 on the top right of the controller inside its casing, instead of having it in the middle.

this causes aim to be slightly off when compared to the perceived point of rotation on the controller.

so my question is, in code, how can i move the center of rotation of each gyro axis on the mpu 6050 so that there centers of rotation are ruffly in the middle of the controller?

2 
void startingGyroSettings(){

  float filteredGyroX = kalmanGyroX.updateEstimate(gz);
  float filteredGyroY = kalmanGyroY.updateEstimate(gx);

  float accConversion = 16384;
  float gyroConversion = 16.4;

  baseGyro.x = round(((gx) / gyroConversion));
  baseGyro.y = round(((gy) / gyroConversion));
  baseGyro.z = round(((gz) / gyroConversion));
  if(gyroAngleStart){
  calibrateGyroEnabled = true;
   // resetGyroAngles();
  
    gyroAngleStart = false;
  }
  else{
    
  }
  if(calibrateGyroEnabled){
     calibrateGyro();
  }
  else{
  baseGyro -= gyroOffsets;
  }

  baseAcc.x = (ax / accConversion);
  baseAcc.y = (ay / accConversion);
  baseAcc.z = (az / accConversion);

  gyroAngles += ((baseGyro) * deltaTime);
  //gyroAngles += gyroOffsets;
  if(URB){resetGyroAngles(); gyroAngles.setZero();}

  float pitch = atan2(baseAcc.y, baseAcc.z) * 180.0 / PI;
  float roll = atan2(baseAcc.x, baseAcc.z) * 180.0 / PI;
  if (roll < 0) {roll += 360.0; }
  if (pitch < 0) {pitch += 360.0;} 
  //roll = offsetAngle(roll, rollOffset);
  //pitch = offsetAngle(pitch, pitchOffset);
   
  //controllerAngles.x = (0.96 * pitch) + (0.04 * gyroAngles.x);
  //controllerAngles.y = (0.96 * roll) + (0.04 * gyroAngles.y);

  //if(gyroAngleStart){resetGyroAngles(); gyroAngleStart = false;}
  //controllerAngles.z = gyroAngles.z;

  controllerAngles.x = gyroAngles.x;
  controllerAngles.y = gyroAngles.y;
  controllerAngles.z = gyroAngles.z;

  

  //baseAcc.print();
  //controllerAngles.print();
  //gyroAngles.print();
  if(gyroLocalSpace){
  controllerAngles.x = degreesToRadians(controllerAngles.x);
  controllerAngles.y = degreesToRadians(controllerAngles.y);
  controllerAngles.z = degreesToRadians(controllerAngles.z);
  float localGyroX = baseGyro.x * cos(controllerAngles.y) * cos(controllerAngles.z) + baseGyro.y * (sin(controllerAngles.x) * sin(controllerAngles.y) * cos(controllerAngles.z) - cos(controllerAngles.x) * sin(controllerAngles.z)) + baseGyro.z * (cos(controllerAngles.x) * sin(controllerAngles.y) * cos(controllerAngles.z) + sin(controllerAngles.x) * sin(controllerAngles.z)); 
  float localGyroY = baseGyro.x * cos(controllerAngles.y) * sin(controllerAngles.z) + baseGyro.y * (sin(controllerAngles.x) * sin(controllerAngles.y) * sin(controllerAngles.z) + cos(controllerAngles.x) * cos(controllerAngles.z)) + baseGyro.z * (cos(controllerAngles.x) * sin(controllerAngles.y) * sin(controllerAngles.z) - sin(controllerAngles.x) * cos(controllerAngles.z)); 
  float localGyroZ = -baseGyro.x * sin(controllerAngles.y) + baseGyro.y * sin(controllerAngles.x) * cos(controllerAngles.y) + baseGyro.z * cos(controllerAngles.x) * cos(controllerAngles.y);
  baseGyro.x = localGyroX;
  baseGyro.y = localGyroY;
  baseGyro.z = localGyroZ;
 // baseGyro.print();
  }

  gyroMouse.x = applyDeadzoneNonAbsolute(baseGyro.x, gyroDeadzone);
  gyroMouse.y = applyDeadzoneNonAbsolute(baseGyro.y, gyroDeadzone);
  gyroMouse.z = applyDeadzoneNonAbsolute(baseGyro.z, gyroDeadzone);

  gyroMouseDelt = (gyroMouse - gyroMouseLast) * deltaTime;
 
  gyroMouseLast = gyroMouse;
  
  float gyroJoyRange = 45;
 
  gyroJoystick.x = mapFloat(gyroAngles.x, -gyroJoyRange, gyroJoyRange, -127.5, 127.5);
  gyroJoystick.y = mapFloat(gyroAngles.y, -gyroJoyRange, gyroJoyRange, -127.5, 127.5);
  gyroJoystick.z = mapFloat(gyroAngles.z, -gyroJoyRange, gyroJoyRange, -127.5, 127.5);
 
  gyroJoystick.x = applyDeadzoneAbsolute(gyroJoystick.x, 127.5 * 0.4, 127.5, 0);
  gyroJoystick.y = applyDeadzoneAbsolute(gyroJoystick.y, 127.5 * 0.4, 127.5, 0);
  gyroJoystick.z = applyDeadzoneAbsolute(gyroJoystick.z, 127.5 * 0.4, 127.5, 0);
  
  gyroJoystick.x = constrain(gyroJoystick.x, -127.5, 127.5);
  gyroJoystick.y = constrain(gyroJoystick.y, -127.5, 127.5);
  gyroJoystick.z = constrain(gyroJoystick.z, -127.5, 127.5);
 
  gyroMouse.x *= gyroMouseSensitivityX * (1 + pow(fabs((gyroMouseDelt.x * gyroDeltMultiplier)), gyroDeltPow));
  gyroMouse.y *= gyroMouseSensitivityY * (1 + pow(fabs((gyroMouseDelt.y * gyroDeltMultiplier)), gyroDeltPow));
  gyroMouse.z *= gyroMouseSensitivityZ * (1 + pow(fabs((gyroMouseDelt.z * gyroDeltMultiplier)), gyroDeltPow));


if(gyroRAF){
  //float smoothedMouseX = mouseXFilter.addValue(mouseX);
  gyroMouseOut.x = gyroRafX.addValue(gyroMouseOut.x );
  gyroMouseOut.y = gyroRafY.addValue(gyroMouseOut.y );
}
Serial.println(gyroMouseOut.y);
  gyroMouseOut.y = degreesToStick((gyroMouse.z), maxDegreesPerSecond);
  gyroMouseOut.x = degreesToStick(gyroMouse.x, maxDegreesPerSecondY);
  
  if(gyroLowPass){
    gyroMouseOut.x = gyroLpfX.update(gyroMouseOut.x);
    gyroMouseOut.y = gyroLpfY.update(gyroMouseOut.y);
  }

  if(GMB_On_Off == 0 && gyroModifierButton){
    gyroMouseOut.setZero();
    gyroJoystick.setZero();
    resetGyroAngles();
 
  }
  if(GMB_On_Off == 1 && !gyroModifierButton){
    gyroMouseOut.setZero();
    gyroJoystick.setZero();
    resetGyroAngles();
  }
}
this is the code i use for the gyros if its helpfull
3

this is the code i use for the gyros if its helpfull

4

Are you sure? Of your need to move the center?

For a gyro mounted on a rigid body, the angular velocities are not different in different parts.

You could try an experiment by placing the gyro in the center (of something) and compare it to having it offset from the center by a similar amount.

a7

5

I’ll take a SWAG (Scientific Wild-Assumption Guess) and suggest that you might be able to adjust the readings by adding or subtracting an offset. I really do not know for sure.

6

i am pretty sure yea. imagine removing the steering wheel from a car and then re attach it at the edge of the steering wheel, then try to steer the car. and i can feel the difference between my controller and various controllers on pc using software to use the controllers built in gyro chip as a mouse

7

i dont think this will work because i all ready do that to stop the gyros drifting like you would with most gyro outputs and if you were thinking of the chips angle values around there axis's from 0 to 360, im not talking about those im talking about the gyro values witch are more like mouse values meaning they should be 0 if the chip is not rotating

8

though if i knew how to do it with the 0 to 360 angles i could figure out how to apply it to the gyro values

9 
void moveGyroRotPoint(){
   float centerX = -10;//neg moves to the left
   float centerY = -10;//neg moves down
   float theta = 0;
   
   float radians = theta * (M_PI / 180);
   
   float translatedX = gyroMouseOut.y  - centerX;
   float translatedY = gyroMouseOut.x - centerY;

   float rotatedX = translatedX * cos(radians) - translatedY * sin(radians);
   float rotatedY = translatedX * sin(radians) + translatedY * cos(radians);

   gyroMouseOut.y = rotatedX + centerX;
   gyroMouseOut.x  = rotatedY + centerY;
}
10

this seems to do it but now i need to figure out what values for centerX and centerY correlate to the position on the controller i think the center or rotation should be

11

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