Can anyone tell me hoe to get a 555 to time out after the imput signal train stops. Currently I have a 555 configured as a one shot which works great except for the fact that it starts timing at the first toggle of the input. What I need is for it to start timing when the input stops toggling. What I mean is that as long as I continue to get an input the timer will be constantly resetting until the input stops and then the timer will time out. I'm using it for a occupency sensor so as long as I detect movement I want to stay on and when I no longer detect movement it will then time out and shut off. Any suggestions are appreaciated. Thanks