Directional BLE receiver


#1

David
I’m seeking a BLE receiver that has a limited azimuth so it could essentially serve as a limited directional receiver. For example, a receiver with an azimuth of 90+/- degrees could discriminate between beacons on the left vs beacons on the right of an outdoor area.

Indoors the reflections off surfaces would likely complicate issues. My purpose is not to limit the omnidirectional character of a beacon transmission, only that of the receiver.

Perhaps this an idea? Is this even possible?


#2

Hello,

I love your email address! It honors two major deities in any nerd’s pantheon.

This is an interesting idea. I’ve not heard of it being done. I’m thinking that a better approach might be to have two adapters connected to a Linux box (Windows can’t do two) at some distance to each other along an axis from left to right and compare the signal strength of the beacon transmitter for each adapter. You could use the Proximity profile (https://www.bluetooth.org/docman/hand…).

Depending on how apart the receivers were, you could calculate the direction with some accuracy, I think.

Otherwise if you were only using one adapter, using some kind of shielding (grounded metal?) to attenuate reception in directions you are not interested in?

Is the Beacon going to be moving and you need to find it?

David Roberts
Plugable Technologies


#3

Hi David,
Thanks for your generously thoughtful response.

The goal is to discriminate beacons in proximity to a defined field of view.

We don’t need to track the moving beacon, but we do want to know if it is within a specific field of view. Whether the beacon is essentially a BLE on a phone or a BLE beacon on an object we want to determine is in the field of view.

I’m not an RF expert (I used to know at least one), but it would seem to me that shielding the receiving antenna to attenuate reception would be a viable solution. But 2.4 GHz may cause issues.

For example, we may want to know who just walked in the door of the store, and distinguish that BLE UUID with all the other BLE UUIDs that are already in the store. Or determine who is in the far left corner from who is in the near right corner.

Kind regards,

Capt Kirk


#4

Hi Capt,

I’m sorry for the delay in answering. I was thinking about an answer to some of your concerns, but then I got called to another task and didn’t finish my reply.

Depending on the size of the store, it still seems possible to use something like one of our USB 2.0 10-meter active USB extension cables to put a Bluetooth adapter like ours in each corner of the store. Then your could monitor the location of each beacon through relative signal strength on the adapters in the four corners.

If the store was larger than about 18 meters square, you could probably set up a grid system.

David


#5

David,
No worries about delay.
Thanks for the suggested solution, let me review that with our team.

Best,
Capt.


#6

Hi Capt.,
Yes, this is possible, but not with a smartphone as you’ve already noticed. I’m not a Plugable employee, but a close consultant and have been working on some solutions for this issue. Please contact me off-list at bill (at) consultcodeblue (dot) com.

Bill


#7