Light sensor that can detect the light emitted from my Android mobile device

Hello all,

I am working on an Arduino project that will deter students from using their mobile devices during in-class instruction.

I have conducted some research and I have failed to find an answer to my question.

My question being: Is there a light sensor that I could place/attach on the screen of an Android mobile device that will detect - based on the light emitted from a mobile device - when a mobile device is in use?

Thanks.

-Highroad

The light from the screen would be bright enough to be detected by an LDR if it was actually on the screen.

I cannot see students agreeing to having an LDR and wires on their phones. Simply moving the sensor or phone and you can override the sensor.

Weedpharma

Google "cellphone jammer".