Accelerometers are widely used in applications, such as condition measurement, motion tracking, and vehicle monitoring. Most handheld smart devices, such as smart phones and tablets, employ accelerometers for motion tracking. The size constraints of such devices has provided the impetus to develop precise, affordable, compact, and power-efficient accelerometers. Microelectromechanical systems (MEMS) accelerometers meet these strict requirements, thus explaining their wide adoption in the smart device market. The increasing cost-performance ratio, particularly regarding accuracy and bandwidth, of modern MEMS accelerometers enables their use in demanding measurement applications. This research introduces an open source battery-powered Internet of Things MEMS accelerometer called Memsio. Memsio is a versatile wireless sensor unit that can be deployed to measure a wide range of different motions. It is operated from a web browser, thus rendering it remotely accessible via smart phone, tablet, or computer. Furthermore, Memsio offers high-speed motion data acquisition capabilities and can store extended measurement periods lasting dozens of minutes; in addition, its wireless and portable nature eases integration in condition monitoring applications. The study presented reports on the construction and functionality of Memsio. Additionally, the functionality of Memsio is demonstrated in the measurement of translational movement of a linear actuator and the vibrations of large rotating machinery.