Some On the use of low-cost MEMS-based accelerometers

Abstract

Since more than two decades capacitive sensors based on Micro-Electro-Mechanical Systems (MEMS) have revolutionized industry and equipment based on their low cost and small size. Accelerometers have been included in all kinds of devices improving automation and process control. Their technical specifications make them useful for applications with frequencies up to a few hundred Hz, such as IMUs, robotics, monitoring, automotive dynamics, cell phones, human interface, sports and medical devices. In this case, sensor performance and reliability are properly ensured in the framework of a fixed installation with preset parameters. On the other hand, some well-known manufacturers provide general-purpose accelerometers based on this technology at competitive prices and covering a specific application range. Given the enthusiasm for modern and low-cost technology, the use of analog and mainly digital MEMS increases continuously, due to their comparative advantages. In the present work, the possibility of designing general-purpose accelerometers, including vibration monitoring and testing, using commercial MEMS chips is analyzed. The constructive requirements that allow to fully exploit the electrical characteristics of the sensor, by means of a suitable mechanical and electrical operating environment, are studied. Starting from an accelerometer chip as an example, a sensor is built, which is then tested and calibrated at low frequency. The sensor proves to be reliable for general use, within the actual measured technical specifications.