This semiconductor gas sensor detects the presence of combustible gas and smoke at concentrations from 300 to 10,000 ppm. The sensor's simple analog voltage interface requires only one analog input pin from your microcontroller.
The InvenSense MPU-6050 sensor contains an accelerometer and a gyroscope in a single chip. It is very accurate, this sensor is used in self balancing robots, drones, smartphones, etc. The sensor uses the I2C-bus to interface with microcontroller.