If you are PIC fan, it it is much easier to design such circuit than using 555 timer. Any further adjustments would be easy since no hardware to be replaced, instead, it is only changing delay time in the software.
How do you propose to end the continuous pulse train that occurs from S2? What I mean is, after S2 is pressed and pulse train starts, what would end the pulse train?
How do you propose to end the continuous pulse train that occurs from S2? What I mean is, after S2 is pressed and pulse train starts, what would end the pulse train?
You need two 555 timers (or a 556 dual timer). Connect the trigger of one 555 configured as a 4.5ms one-shot to the output of the second 555 connected as an astable with a period of 0.5s. Use S1 to trigger the one-shot. Use S2 (SPDT) to connect either S1 or the astable to the one-shot.