I am using a 555 Timer to control a motor for a science team project. I have to make a Rube Goldberg-like machine and I am not allowed to use Arduinos or Raspberry Pis. However I need to trigger the motor and then have it turn off by itself, after a set amount of time. I have been trying to do this with a 555 timer and have had a little luck, but not a ton. So any help in figuring this out (maybe a circuit diagram) would be appreciated.
I want to motor to trigger for about 8 seconds (I know how to do the resistance calculations and figure out the size to use, so this can be worked out later) when I close a circuit/create a high signal. To do this, I have been using an inverted 555 set up, which lets me use a high voltage as a trigger. However, I cannot figure out how to either make this behave as a pulse, maybe using a capacitor, or to configure the 555 timer to use the start of a high signal as the start of the timer.
Really, I just want to know if there is a way to make a sustained signal behave as a pulse for a 555 timer, possible with capacitors, and how to do it.
Specifications: Just a small motor DC circuit motor (I forget what the specifications are, but easily battery powered), 4 AA batteries in series. Other than that, it's your standard series circuit. I can use some small microcontrollers or ICs.