Bluetooth Interference

[bruno.dedeyne]

Hello,
Currently I'm working on a project in the area of presence detection. I'm inventorizing the current techniques that can be a solution to my use cases.
One of the techniques with bluetooth.

Here I want to know how i can get the Bluetooth RSSI's of my mobile phones (without setting the discoverable option on on the phone). I tried with HCITool, but you need a connection first.

Second I want to know if there is a way on how to measure interference in a Bluetooth field. When you connect a RPI with a mobile phone, you create a Bluetooth blob/mesh. When someone walks in the space, he interfers the blob. I want to measure this to get the number of people in a room.

Both of the problems with RPI.

Anyone have an answer?
Thanks!

[Andyroo]

Not sure if this will help you http://www.digifail.com/software/bluelog.shtml

They suggest to use two devices to measure travel time but the scanning side may be of help.

[Douglas6]

When trying to connect to a Bluetooth device, 1 or 2 seconds elapse negotiating the connection (assuming that Bluetooth is turned on on the device/phone) . During this time, you can query for the RSSI.
As far as a "Bluetooth blob/mesh", I have no idea what you are talking about.

[bruno.dedeyne]

The purpose of the 'blob' is:
when you have 2 mobile phones with bluetooth on, they send out beacon through a certain space. they create a virtual 'blob' or area where there is bluetooth connection. When you have 2 mobile phones connected, you have a link between them, creating the same 'blob'.
My question here is, when a person walks through this blob, how can i measure it?

[Douglas6]

You can't. There is no 'blob', to begin with. There are two transceivers with a certain range. A body walking directly between them may effect RSSI, but very probably won't.

[Andyroo]

The purpose of the 'blob' is:
when you have 2 mobile phones with bluetooth on, they send out beacon through a certain space. they create a virtual 'blob' or area where there is bluetooth connection. When you have 2 mobile phones connected, you have a link between them, creating the same 'blob'.
My question here is, when a person walks through this blob, how can i measure it?

The only hope you have is to find a chipset the can return a detailed level of RSSI. I cannot find a clear definition of BLE RSSI but if it’s anything like the 802.11 spec manufacturers can set the value as they determine (0-255 in the WiFi case) and as it’s a quality then you may get some info BUT this would also have to take into account any harmonics, new devices, power fluctuations etc.
Looking at the triliteration tests (esp fig 4) in this report https://www.researchgate.net/publicatio ... ular_paper the changes at one meter is 12dBm in seconds with no obstructions!

All in all I think you are not going to get a result from this