light operated switch application

i have a switching circuit using LDR but i need some application for it!! aside from the streetlights... ineed some advice!! please help, thanks!!

You can use it to transmit data.
1.Create a Led driver section.
2.send somdata logic 1 or logic 0 to the driver so that the led can switch
3.Use the LDR and Convert hte light to the data which is been transmitted