Limit Number Of Pulses From 555 Or Similar
You can have one 555 timer be the enable for a second 555 timer. One in mono-stable mode and the other oscillating at whatever frequency your pulses need to be at. Then just make the first 555's single pulse long enough to contain how ever many pulses of the second you want.







simulate this circuit &ndash; Schematic created using CircuitLab

Note the pin numbers are not in the same spots for the two packages. This was drawn pretty quickly, so also check for errors :)