Use a BLE sniffer (nRF51822) to sniff phones (i.e. non peripherals?)

[victorhooi]

I just wanted to confirm - this project uses the RPi's inbuilt BLE dongle, right?

So it would only be able to pickup BLE devices that are actively advertising, or trying to pair (e.g. headphones).

However, it won't detect devices like phones.

What do you think about using a full BLE sniffing dongle like this one:

https://www.adafruit.com/product/2269

to passively sniff all BLE conversations?