Strobe rockets function similar to strobe stars in that the reaction oscillates between flash and smoulder phase. The first formula given to me by John Steinberg can have the barium sulfate replaced with various other metal sulfates to obtain different colors.
DANGER: Copper sulfate can not be used in the first formula to produce a blue strobe. Copper sulfate absorbs moisture readily from the surrounding atmosphere. This moisture would then cause the magnesium and ammonium perchlorate to react producing heat, and eventually spontaneous combustion