[HELP] Timing circuit advise

[eight08]

I'm trying to build a circuit that would trigger at a certain amount of time, and then repeat.

What is the best design plan?

 

[siggy]

555 astable with a duty cycle less than 50%

R1 >= R2 iirc

 

[siggy]

Duty cycle is time on

1% to 49% is short on longer off
50% on off equal
51% to 100% is longer on short off

 

[jackorocko]

I'm trying to build a circuit that would trigger at a certain amount of time, and then repeat.

What is the best design plan?

What is the time period length you are interested in, mark space ratio? How accurate does the timer need to be? Have you read the sticky about timers?