We propose to attach a small stroboscopic light source to a moving object and connect the source to
a pulse generator with the help of insulated thin flexible multi-cored wires. Students can assemble
such a device independently in a school laboratory. The device can be used to obtain trajectories
with time marks in students’ research projects in mechanics. In the paper we give an example of the
application of stroboscopic photography in a demonstration experiment devoted to inertia.