There have been developed a children’s smart clothing prototype reacting to microclimate changes by signalling with the help of an optical fibre fabric output interface and a mother’s purse receiving the given data via wireless communication and displaying it on an LCD screen. During the research, the optical fibre fabric was tested in order to determine its reaction to external stimuli and define its layout within clothes. Child jacket’s logic was based on Arduino LilyPad. On the other hand, AVR microcontroller was used in pursue, which yielded a more economical and compact solution, although it was not as developer-friendly as LilyPad.