The master thesis deals with the design of device used for gun prototypes testing purposes. It aims at electrical part of the design which controls a stepper motor which through mechanical gear initiates trigger of tested prototype periodically. The core of design consists of the DRV8711 integrated circuit which controls a stepper motor. The integrated circuit is using the microstepping driving technique. The main logic of designed device is controlled by PIC32 microcontroller unit which also communicates with PC through USB bus