How to Design a Variable Timed Circuit Cut Off?

[GreasyBob]

im really drawing a blank on this one...

been a while since i done timers and its late!

im totally lost i need help designing a varible timed circuit cut off,
but it needs to be activated by a push to activate switch.

the timing on this literally needs to be 1-2 possibly even 3 seconds, to operate a motor,
and needs to be able to work time after time. its going to be running 8.4 to 9.6v

any help or pointing me in the right direction would really help

 

[negitron]

You want something like this:

http://www.bowdenshobbycircuits.info/page9.htm#555mono.gif

Instead of the relay, you'd drive a power MOSFET which would, in turn, drive your motor. Increase the size of the timing capacitor to lengthen the ON time.