How to monitor several beacons in an open area with one Hub.

RE: How to monitor several beacons in an open area with one Hub.

David Edwin — Wed, 04 Oct 2017 08:43:45 GMT

wizwiki.net/.../doku.php , seems to have already done the nRF5x to Ethernet integration. PoE integration also seems to be available so a hub solution for a controlled environment seems to be possible. See also devzone.nordicsemi.com/.../

RE: How to monitor several beacons in an open area with one Hub.

Roger Clark — Tue, 07 Mar 2017 23:47:13 GMT

The information Pixie was vague.

The only statement I can find on location accuracy is "within inches", which is open to a lot of interpretation e.g. 6 inches, 12 inches, 18 inches.

Their youtube video was uploaded in 2015 and the last comment was a year ago.

The implication was that they use a mesh network, but they may simply be scanning and then rebroadcasting the RSSI and MAC address of every device they can hear.

I couldn't see any data on the battery life. They are a very small product, so the battery capacity is only likely to be 500mAH at the most, (probably less)

Mesh networks are power hungry, so I wonder how long each tag lasts. BTW. I noticed a comment on YouTube that the batteries were not replaceable.

Edit. Thinking about the mesh networking, perhaps full mesh functionality is only needed when the user wants to locate a beacon. So perhaps they normally just adveritse

RE: How to monitor several beacons in an open area with one Hub.

endnode — Tue, 07 Mar 2017 18:35:21 GMT

Hi Vikindio, all what I've found about Pixie seems to work with >5m accuracy (e.g. here they claim 10-45m which seems to be perfectly in-line with BLE RSSI experience from such basic solutions). Do you have more details explaining how ANT mesh, BT5.0 mesh, nRF52840 and location tracking relates to each other in your solution? So far it doesn't make much sense and it prevents us to give you more specific answers. Also as far as I know nRF52840 is just preview (= pre-production) version with pretty extensive anomaly list and poor SW support. Full production versions should come in the end of 2017, I'm wondering if this influences your project...

RE: How to monitor several beacons in an open area with one Hub.

Vikindio — Tue, 07 Mar 2017 17:41:51 GMT

Thanks Sigurd. We will get our BLE 5 chips by end of this month, and we are exciting to start putting together our beacons. But we still having a hard time to find the right hub/receiver that can read all this beacons and at the same time work in a mesh networking, the key factor of why we are using this BLE 5. Or should we just aim to build our own hubs/receivers? do you have any suggestion what should be the best parts/technology to use on this hubs/receivers? The software we are developing will have several functionalities and options, but from the beacons and hub side, they will only be doing monitoring/positioning, we will use as less amount of data as possible for better battery life. So small data to position them is the key. We have as a reference "pixie point" that can position the beacon by inches, and thats impressive and thats what we aim for. Any suggestion and info about this will be highly appreciated Sigur, thanks!

RE: How to monitor several beacons in an open area with one Hub.

Vikindio — Tue, 07 Mar 2017 17:35:49 GMT

Thanks Roger. ANT is a must for our system, the new nRF52840 BLE 5 comes with mesh networking and its a key factor for our system. We will get these chips by the end of the month, and we will start putting the beacons together. But we are still trying to look for the right hub/reader that can handle a mesh network and a bunch of beacons at the same time. We got as an example the new sensoro that looks and by the specs. works fantastic. Then also we have the "pixie point" that triangulats the beacons by inches, and thats impresive and thats what we are aiming for. Do you have any suggestion on how we should triangulate the BLE 5 beacons? any hub/reader you know of that could help us to start with this?

RE: How to monitor several beacons in an open area with one Hub.

Vikindio — Tue, 07 Mar 2017 17:31:12 GMT

Hi Daniel. Doesnt matter usb or ethernet. But yes the PC will be the one handling all the triangulation and data from the beacons. I have not yet found out what would be the best way to do the triangulation, we are working on the prototype right now. But this must be as simple as possible and reliable, its for big companies we are developing this. Do you have any suggestion for the hubs/readers ? As mentioned before, we just got our hands on the latest BLE 5 nRF52840 that will have mesh network capabilities, as well with other goodies, but we want to have a very low consumption of energy, and limit the data transfer only for positioning. the software will have several function specific for the company, but the beacons and hubs/readers will do what they do best, positioning. Just recently PIXIE POINT is able to position the beacon by inches, thats amazing and that is our aim point.

RE: How to monitor several beacons in an open area with one Hub.

Sigurd — Tue, 07 Mar 2017 14:27:31 GMT

Note that you should in theory be able to scan/monitor all these beacons running a nRF52 in central mode. The time it takes before all beacons are scanned will depend on much packet collision the beacons causes, advertising interval, scanner settings, etc. E.g. here, a user scanned 80 different BLE devices in his building using a nRF51 in central mode.

RE: How to monitor several beacons in an open area with one Hub.

endnode — Tue, 07 Mar 2017 10:50:46 GMT

Hi Roger, to be fair you can make it work but there is some non-trivial effort needed. There are commercial solutions using BLE for real-time location service with <2m accuracy but these are just few on the planet and teams were working on them for 3+ years. There is also load of patents around that so you might have problem if you reinvent something and want to make money on it...

RE: How to monitor several beacons in an open area with one Hub.

Roger Clark — Mon, 06 Mar 2017 22:42:51 GMT

If you didn't want ANT, I'd suggest a Raspberry PI (or the new RPi Zero W if you can use Wifi instead of Ethernet) but I don't think any of the RPi board have ANT (though you should check)

Apart from that, I suspect your next best option is to attach a nRF52 to a RPi as a SPI slave, and have the nRF52 handle the monitoring, and use the RPi for transmission via Ethernet to wherever the data is needed.

If you are willing to write the drivers, you could directly connect an Ethernet module to the nRF52. But I suspect for a prototype it would probably be easier to use the RPi for the Ethernet connection.

Edit.

BTW. Triangulation via RSSI is extremely inaccurate. There are multiple posts on this forum about using RSSI for distance measurement and triangulation and I have never seen one where anyone got it to work well.

RE: How to monitor several beacons in an open area with one Hub.

Daniel Wang — Mon, 06 Mar 2017 21:19:39 GMT

The hub needs to be connected to the PC by Ethernet? Why can't you use USB? Is there any more requirements? Where do you process the data and do the triangulation? On the PC? What are you planning to use to do the triangulation? RSSI?