The article presents the experience of organizing the use of wearable electronic devices (fitness trackers) by schoolchildren to solve the problem of low physical activity. The existing methods of motivating schoolchildren to increase the level of physical activity do not give the desired result. Physical education classes in school cannot compensate for the movement deficit. During extracurricular hours, most schoolchildren also cannot organize their physical activity independently and choose sedentary types of leisure. One way to tackle the problem is to encourage the use of fitness trackers. The use of fitness trackers allows the teacher to monitor the level of physical activity of schoolchildren, analyze the achievements jointly, and help organize the physical activity of schoolchildren outside the classroom. To solve the problem, the authors of the article have developed two experimental programs of supplementary education for schoolchildren with the use of fitness trackers. The first program involves the regular, supervised use of fitness trackers in animation training. The second program includes training assignments for assembling and testing fitness trackers in the course of programming training. The second program showed higher efficiency. For the statistical assessment of the results of the educational programs implementation, the Wilcoxon T-test was used. The implementation of educational programs led to increase of the level of physical activity of students by 7–15 %. The authors give recommendations on the use of fitness trackers in the supplementary education system.