Detect Smartphone Presence

Hi!!! Firstable, Thanks in advance :)

I'm looking for a system/sensor able to detect a Smartphone presence, similar to RFID, but without TAG card.

I want to aproch the phone to a sensor to activate "xxxx" and, if you aproch the phone one more time, deactivate "xxxx"

Some ideas???

Thanks!!!

aerls: Hi!!! Firstable, Thanks in advance :)

I'm looking for a system/sensor able to detect a Smartphone presence, similar to RFID, but without TAG card.

I want to aproch the phone to a sensor to activate "xxxx" and, if you aproch the phone one more time, deactivate "xxxx"

Some ideas???

Thanks!!!

Nothing to it. The device is called a radio receiver. What are the Smartphone frequencies you would like to monitor?

Paul

Bluetooth module?

Just like those dangly trinkets and battery stickers for the old Nokia phones of the late 90's - early noughties.

Look up CDMA or GSM operating frequencies. Find a receiver for those frequencies. Figure out what the heck 'xxxx' is.

Step 1. Detect phone Step 2. "xxxx" Step 3. Profit

The problem is a phone is not transmitting all the time, its bursty and there can be long gaps. If BT and NFC aren't enabled it won't respond to either of those.

Why not just detect humans, they all have smartphones these days!