Do you have access to the blinking light? or you are wanting to adapt your device to existing hardware that you have no control over? if you dont have access to the light, then it sounds like you have the components that you need to start. I created a small project to sense low light in a theater room so that when you are watching a movie or have the lights off, inside the movie cabinets, it will sense the low light upon opening the door and turning on some low light leds so you can see the movies and pick another to watch..
All i used was uno, resister, LED strip and photocell.