mpu6050实例化失败，求教！

niejianyong

库文件也是论坛下载的，代码也是，都是一个帖子里面的
库文件（.h + .cpp 在libraries目录下的mpu6050下放的，libraries也有同样的文件）
但是：出现实例化失败可能是哪方面的原因，求指点，谢谢
#include "Wire.h"
#include "I2Cdev.h"
#include "MPU6050.h"
MPU6050 accelgyro;  （出错）

sketch_dec16a:14: error: 'MPU6050' does not name a type
sketch_dec16a.ino: In function 'void setup()':
sketch_dec16a:33: error: 'accelgyro' was not declared in this scope
sketch_dec16a.ino: In function 'void loop()':
sketch_dec16a:45: error: 'accelgyro' was not declared in this scope

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