Stroboscopes are commonly used to examine moving machinery in an industrial setting. The stroboscope allows the equipment to be inspected or monitored while it is operating.
If the strobe frequency is high enough, the observer won’t perceive the flashing of the light, similar to how one does not notice the fact that a movie projection actually consists of individual frames.
This article details construction of a control circuit that can drive an array of LEDs for use as a stroboscope. The LED array can be made by straightforward modification of inexpensive LED flashlights, or a custom array can be built.
One note of caution. Some people who have epilepsy are susceptible to seizures caused by rapidly flashing lights. Do not use the device shown here, or any commercial strobe light around anyone who is known to have such a susceptibility!
Here is a YouTube video demonstration of just a few ways that this stroboscope unit can be used to view moving objects.