Sorry, it is my first time in this forum and I am a hobbyist. So far I see that the responses have been more specific than my requests.I suggest that you give us a CLEAR exact specification of your ideal requirement. There have been many suggestions that seem to meet your original specification but you seem to have found a problem with all of them. One particular thing is not clear. does the door have to be moving to flash the light or just NOT at the fully closed or fully open positions. The fact that you have now told us that it is a roller door means an optical encoder could be fitted to the roller shaft to detect motion. (Either when driven by hand or by the motor.) This could be as simple as painting black and white stripes at some point on the shaft and mounting a reflective opto sensor close to that point on the shaft. Adding sound is not a problem. If you used the limit switch suggestion a push button could be added to cancel the alarm. It could go back to normal next time the door reached one of the limit switches.
I want the warning light trigger to be any goor roller motion. No motion, no warning light at all. During motion, blinking warning light (as I stated at the beginning that my knowledge has only lead me to a design that turns it on solid during motion). Blinking has stumped me.
And I do appreciate all your inputs. Every morning before I go out to bake in the hot summer sun (yes, where I am it is now summer while in many other parts of the world it is simultaneously winter) to run wires, I eagerly login to read this helpful thread.
So even before we finish... THANK YOU!!!