Cocos2D and iPhone's accelerometer - iphone

Question

good afternoon!
Today I've started to develop a game and I got a trouble. So, first at all I would like to say that I have no experience developing games...
So, I've a CCSprite in the layer and I want to move this between the scene with a margin (top, bottom, left and right).
The minimum X should be -0.8 (in X-axis using the accelerometer) and the maximum 8. The minimun Y should be -1 (in Y-axis) or 0 in Z-axis and the maximum 0 (in Y-axis) or -1 (in Z-axis).
Ok, knowing this, I've tried to do this using the range between minimum and maximum space and accelerometer value but I haven't getting this working vertically (Y-axis on the iPhone). Then I got a done code in the web but this don't works when I want to move the object to back (the object only goes).
Did someone know how to fix this?
My actual code:
- (void)updatePosition:(ccTime)dt {
CGSize winSize = [[CCDirector sharedDirector] winSize];
float maxY = winSize.height - car.contentSize.height/2 - 20;
float minY = car.contentSize.height/2 + 20;
float newY = car.position.y + (carPointsPerSecY * dt);
newY = MIN(MAX(newY, minY), maxY);
float maxX = winSize.width - car.contentSize.width/2 - 40;
float minX = car.contentSize.width/2 + 40;
float newX = car.position.x + (carPointsPerSecX * dt);
newX = MIN(MAX(newX, minX), maxX);
car.position = ccp(newX, newY);
}
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {
float speedY = acceleration.y * 500;
if(carPointsPerSecY < speedY) {
carPointsPerSecY = MIN(carPointsPerSecY + 10, speedY);
} else {
carPointsPerSecY = MAX(carPointsPerSecY - 2, speedY);
}
float speedX = acceleration.x * 200;
if(carPointsPerSecX < speedX) {
carPointsPerSecX = MIN(carPointsPerSecX + 10, speedX);
} else {
carPointsPerSecX = MAX(carPointsPerSecX - 10, speedX);
}
NSLog(#"Acceleration: X (%f) - Y (%f) - Z (%f)", acceleration.x, acceleration.y, acceleration.z);
}

Answer 1

I'm not sure I completely understand what you want but I hope this helps you with your end goal:
-(void)updatePosition:(ccTime)dt {
CGSize size = [[CCDirector sharedDirector] winSize];
int margin = 20;
float speed = 15;
float maxX = size.width - car.contentSize.width / 2 - margin;
float minX = car.contentSize.width / 2 + margin;
float maxY = size.height - car.contentSize.height / 2 - margin;
float minY = car.contentSize.height / 2 + margin;
float newX = MIN(MAX(car.position.x + xAccel * speed, minX), maxX);
float newY = MIN(MAX(car.position.y + yAccel * speed, minY), maxY);
car.position = ccp(newX, newY);
}
//define in header: float xAccel, yAccel;
- (void)accelerometer: (UIAccelerometer *)accelerometer didAccelerate: (UIAcceleration *)acceleration {
yAccel = acceleration.x;
xAccel = -acceleration.y;
}