This thesis describes the design, development and realization of a wireless electronic timer for use in firesport. Specification of the final product is built with regard to versatility, ease of use and low acquisition costs. Commercial products have been compared as inspiration for this work. Requirements of the timer are based on the rules of firesport disciplines, where the timer can be used. It consists of a base station that can be accompanied for additional elements used to starting, splits capturing and stopping. An independent communication module has been created to ensure wireless connection. Libraries for comfort work with the module, support for USB bus and reliable protocol for wireless transmission have been implemented