An apparatus integrated with micromachined (a.k.a. MEMS, Micro Electro Mechanical Systems) silicon thermal sensor as a proximity switch sensor in air/oil Lubricators is disclosed in the present invention. The present invention relates to mass flow sensing and measurement for both gas and liquid phase and relates to air/oil lubrication process for multi-point lubrication machine. The invented apparatus is utilized as an alarm device to prevent mechanical system failures caused by the discontinuity of oil lubrication. The MEMS silicon thermal sensor is distinguished with a variety of advantages of small size, low power consumption, high reliability and high accuracy. In addition to the above benefits, the most significant and critical advantage is its fast response time of less than 20 msec, which makes the proximity switch control become viable for preventing equipment damage from oil lubricants discontinuity.