Is there any way to make an LED display that can find cell phone signals?

I work in a theatre and it'd be awesome to see who has their cell phones still on during performances. I know it's illegal to jam cell reception, but just as a joke to walk around pre-performance and have something that lights up when you're near a cell signal, kind of like a metal detector but a cell signal detector. Is this possible?

lemonie8 years ago
You could make a receiver to pick up transmissions, but what are you going to do about it? Telling people to switch off is your only option whether you detect them or not. As a suggestion: have someone man a spotlight, when one goes off spotlight the user... L
Aarnat8 years ago
I found this, it is quite amazing. My guess is that you can make one "cell" and mount it on a stick like a metal detector.

Have fun!