In my experience, almost anything with a speaker or earphone will detect a cellphone operating nearby :-)
Can anyone verify this is sensitive enough from a few feet away from a cell phone? I think this is what I need!Simple...
I understand that it is my responsibility to build it and test it. But I'm traveling right now and I need to estimate costs for the project so I'm asking for help. I need to order the needed parts, so far none. Not for someone to verify it. Just your thoughts. Will it work at all for my application? If I need more sensitivity an LM358 will be more than enough? Thanks for your help so far!
I was hoping to use the instructable link above with only a single resistor? Maybe 2ft away without Op amp?I understand the power output of a cell phone varies with distance to the tower.