The MPU6050 is an IMU (inertial measurement unit) sensor which is frequently used in self-balance robots, UAVS, and other projects where positioning would be important. Some users have reported that some of these modules have a different I2C id than expected. If this is the case you might experience the module not working as expected. Removing ID check may get the chip to work. You can find more information here. The MC-38 sensor is a magnetic switch that opens/closes in the presence of a magnetic field. It was designed for use with doors, windows, etc. Here is a guide to getting started.