Hi,
The end result that I need to obtain is get a pulse that will last for 30 seconds and then go off (and not go back on).
I figured that would be easy enough to do with a 555 timer in monostable mode ... but I've run into a problem.
There is no way to get the pulse to fire once on startup. If the trigger pin is held high on power-up, nothing happens, if it is held low, LED stays on forever because the circuit keeps re-triggering itself.
To trigger the 555, it requires a high-low-high pulse. So what I need is a high-low-high pulse on power-up to trigger the 555 once. Does anyone know how I could do that?
Are there any other solutions for getting a 30s pulse on power-up? I can't have push buttons in my circuit, so a traditional trigger won't work.
I've been pulling my hair out for almost a week on this thing. Any help would be greatly appreciated!
Micro571