At present, the concept of reaction time measurement is used as one of the methods of psychological testing. Its usage spectrum, however, covers rehabilitation medicine, neurosciences and similar. Available systems used to measure reaction time deal with complex reaction time, i.e. the time between generating the stimuli and respective reaction via effector. Typical limitation is the design of these devices, which usually fits specific application, but it is not reusable for other applications. The goal of this paper is to introduce concept of device measuring reaction time of both upper and lower limbs, to visual or acoustic stimuli. Design of the device allows for application independence, i.e. it is reusable for wide range of different applications. This independence is supported by open software platform, including base set of testing tasks. In case of measurement of upper limb reaction time, the device allows measurement of individual components of the reaction time, opening new capabilities for deeper understanding of human sensory systems with respect to the speed of reaction to external stimuli.