Introduction

Bluetooth interface implementation in RouterOS allows the device to capture Bluetooth advertising packets that are broadcasted over 37, 38, and 39 advertising channels. More information can be found in the guide here.

Bluetooth tags like, for example, TG-BT5-IN and TG-BT5-OUT, do exactly that. They broadcast advertising payloads over the mentioned channels. To understand what kind of information is stored in the payload, make sure to check the link. The tags can be configured (using the MikroTik Beacon Manager app) to broadcast the payloads automatically, with an interval or/and when a movement, tilt, or free-fall trigger is detected. In simple terms, the tag will "tell" (broadcast to) all the surrounding Bluetooth scanners (like the KNOT) information about itself periodically.

When the payload is broadcasted by the tag, and the tag is within the KNOT's Bluetooth operating range, the KNOT will capture and display the payload under its "scanner" Bluetooth interface section. It would look like this:

/iot bluetooth scanners advertisements print
Columns: DEVICE, PDU-TYPE, TIME, ADDRESS-TYPE, ADDRESS, RSSI, LENGTH, DATA
#  DEVICE  PDU-TYPE        TIME                  ADDRESS-TYPE  ADDRESS            RSSI    LENGTH  DATA                                        
0  bt1     adv-noconn-ind  mar/07/2023 12:11:57  public        DC:2C:6E:0F:C0:3D  -51dBm      22  15ff4f09010079100000ffff0000cf188a6b2b000064
1  bt1     adv-noconn-ind  mar/07/2023 12:11:58  public        2C:C8:1B:4B:BB:0A  -49dBm      22  15ff4f090100168dfefffffffeffa51ae1362200005e 

The example above shows us, that the KNOT sees two Bluetooth tags within its operating range with MAC addresses "DC:2C:6E:0F:C0:3D" and "2C:C8:1B:4B:BB:0A", their respective payloads ("DATA" field) and the signal strength ("RSSI" field).

With the help of RouterOS scripting and scheduling, we can make the KNOT automatically-periodically scan the payload list and, in case, a specific payload or a specific tag's MAC address is found on the list, we can make the KNOT structure an MQTT message (out of the printed information shown in the example above) and send it to the configured server via MQTT, e-mail or HTTP post. Script examples will be shown later on in the guide.

As the title suggests, the goal is to implement a Bluetooth tag-tracking solution and the idea is quite simple. When you have 2 KNOTs (KNOT-A and KNOT-B), running the same script on a scheduler, and the tag moves between their Bluetooth operating ranges, the data on the server will indicate whether it was KNOT-A or KNOT-B that have sent the tag's payload. That will help you figure out the proximity of the tag. Whether the tag is broadcasting payloads in the KNOT-A zone, or in the KNOT-B zone.

You will need a server where the data is going to be stored and visualized. In this guide, we will showcase a server called ThingsBoard and how to communicate with it using the MQTT protocol.

ThingsBoard has a cloud solution and different local installation options (on different OS). Since we've added a container feature, it became possible to also run the platform within RouterOS. In order to do that, you will need a RouterOS device that has at least 2 GB RAM, has an option to increase storage (for example, an additional USB port), and is either ARM64 or AMD64 architecture. CHR machine or CCR2004-16G-2S+ could be a good fit.

Setup requirements:

• a running ThingsBoard server;
• 2+ KNOTs with access to the server's network via ethernet, Wi-Fi, or cellular connection (the amount of the units required depends on the size of the area that needs to be covered);
• 1+ Bluetooth TG-BT5-IN and/or TG-BT5-OUT tags (depending on how many assets you need to track - 1 tag per asset).

Scenario explanation

Imagine The same as with Wi-Fi roaming or LTE roaming

If you follow the guidelines, you will be able to implement a setup, where you have the KNOTs scattered around your location.

Logically, if the Bluetooth operating ranges overlap and the tag is within the overlapped area (at the same time within KNOT-A and KNOT-B Bluetooth ranges), both KNOTs will send the data and the server is going to show that the tag is reported by both devices at the same time.

Keeping the above mentioned in mind, you can position the KNOTs across your environment (where you want to track your assets) so that the KNOT's Bluetooth ranges do not overlap with each other but cover the whole area. The actual Bluetooth operating distance can vary from site to site because a lot of different factors can impact it, like 2.4 GHz interference or the surrounding materials used. For example, in line of sight, with no interference, the distance at which the KNOT is able to capture the tag's broadcasted payload, can be up to 180 meters (KNOT — ~180 meters — TG-BT5-OUT). But you also have to keep in mind that with further distance, more packets will be lost on the way. In the office environment, the range can go down to 30-100 meters.

Surely, there will be zones where two or more KNOT's Bluetooth ranges overlap.

You can use it to your advantage → basically, you will have information that the tag, right now, is on the edges of the Bluetooth ranges in-between specific KNOT zones. In other words, when the asset moves into the overlapped area, you will have information on the server that the asset is somewhere between the two KNOT operating ranges, which is useful information to have as it gives more precision.

Or, you can tinker with an additional filter that can be applied to the script (that will be shown later on), which will make the KNOT ignore the payloads that the scanner captures unless the signal strength (RSSI) is higher than the specified value. In the Bluetooth scanner example above, we can see that the KNOT sees one of the tags with an RSSI signal strength of -51 dBm and the other one with an RSSI signal strength of -49 dBm. It is possible 

Bluetooth advertisements

    # whose signal strength is stronger than -40dBm

To understand the scenario and the idea behind it better, take a look at the topology shown below:

Let's say you have a warehouse and you wish to track pallets. Just install the KNOTs in different locations

Configuration

/iot/mqtt/brokers/add name=tb address=x.x.x.x port=1883 username=access_token