Photo sensitive switch problem

Question

  Hello, I am a non-engineer type trying to figure out how to alert an operator that an indicator light is flashing at another location.  Basic parameters are: 
Outside daylight operation.
Can’t be hard wired.  Peel and stick is the desired connection method.
Distance to new location is only 18 inches.
Battery powered.
Light activated (source is approximately 3/8” in diameter). 
Ideally the new light (indicator) would begin flashing if the source light starts flashing and stops when the source stops. 

Answer 1

  Hello, Thanks for responding.  What I would like to develop is a way to alert a motorcycle rider that a turn signal light is still flashing. I constantly see riders (including myself) forget to cancel the turn signal. On motorcycles they do not self cancel. Occasionally it can be misleading enough to pose a danger. I don't think many folks will crack into the bikes electrical system and that is why I would like to see if its possible to do it another way. What I was thinking was a battery powered cluster of 2 or 3 LED's. Ideally the switch would be a phototransistor (if I understand that correctly) that could be a "peel and stick" item that could be put directly over the 3/8" (or so) green light on the instrument panel. Approximately 18" of wire to the LED's would allow the operator to attach it (peel and stick again) higher up on the bike. Perhaps part way up the windscreen. During daylight operation the riders attention is pretty focused on the road and you don't see the flashing light on the instrument panel.
The other way would be a switch designed to "stick" over the existing turn signal switch. They are on-push to cancel-on type of switches.  This would be the preferred choice.  I would run wire to each rear view mirror and stick a LED on the inside edge of the mirror. Riders are constantly checking the mirrors (at least frequently) and I believe would notice that.
Anyway, your thoughts and/or direction would be appreciated.  Thanks, Bill Prather