Alright- to start with, I apologize if this is an easily remedied issue, or if I'm over-thinking it, but - here it goes. Using IC555's, I'd like to build a series of timer circuits that can power up a group of sound equipment with a specific timed procedure. As it is right now, myself and the other audio engineers at this location have to lap the building three times to get all five systems started, and to be frank, we're lazy, and would like to make the start-up process as "newbie-friendly" as possible. The systems have to start up with particular delays, as follows. 1) Console 7-second delay 2) Monitor control system (Avioms) 7-second delay 3) Power rack 15-second delay 4) Main speakers 2-second delay 5) Monitor speakers Without the delays listed, it's possible to cause loud pops damaging to the human ears, or even severely damage some of the equipment in question. (Power-up pops can blow the main speakers pretty readily, and filtering them out is VERY costly. We simply cannot afford the price of the filters.) Also - they have to power down in exactly the opposite order they were powered up, with the same time delays going in the other direction. Now, here goes my thoughts/designs/possibly idiotic musings. What I originally wanted to do was build a timer circuit for each system such that a momentary contact pushbutton powers on the console, then starts a 7-second timer, which then, at the end of 7 seconds, trips the second relay, and starts another 7-second timer, which, at the end of 7 seconds, trips the third relay, and starts a 15 second timer...etc.etc.etc. to basically go through a fully automated power-up sequence. Then for the power-down sequence, have a series of timers going the opposite direction which, at the end of their times, they send a pulse to the first set of timers to stop outputting voltage to the relays to power them off. Here's the problem. An IC555 monostable timer only goes high for the number of seconds decided by using the resistors and capacitors, then drops low again. What this will do is trip the relay, leave it on for x number of seconds, and drop low. This is a problem. Example: Timer 3 is using a 1M resistor and a 10µF capacitor. So - it's low, gets triggered, goes high for 15 seconds, then goes low again. So - the main speakers would turn on for 15 seconds at the beginning of the cycle, and turn off again. How I decided to try to fix the problem. Get the inverse of the output of a 555 monostable timer, and use that to pulse to a 555 bistable latched switch. Problem. The 555 bistable goes high the instant the trigger pulse drops low. Not at the end of the pulse. So - there's no delay. But the bistable latched circuit does what I need it to do. Output high on pulse, and stay high until a pulse comes into the reset pin (4) to power it off. But - the timer still doesn't do what I need it to do (wait 'til x number of seconds passes, then go high.). Now here's my question. Am I over-complicating things horrendously again? Is there a timer circuit I can build that outputs low, takes an input pulse, stays low for X number of seconds, then goes high and stays high until the reset pin is pulsed? In any case, is what I'm trying to do here remotely realistic? Or am I just having illusions of grandeur?