BLE Connector Configuration

• Main section
  • Device object subsection
    • Subsection telemetry
    • Subsection attributes
    • Examples of data converting
    • Subsection attributeUpdates
    • Subsection serverSideRpc
• Next steps

This guide will help you to get familiar with BLE connector configuration for ThingsBoard IoT Gateway. Use general configuration to enable this extension. We will describe connector configuration file below.

BLE connector need some system libraries, to install them please select version of package manager in your system below and run a command to install libraries:

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sudo apt-get install -y libglib2.0-dev zlib1g-dev

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sudo pip3 install bleak

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sudo yum groupinstall -y "development tools"

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sudo pip3 install bleak

Example of BLE Connector config file.

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{
    "name": "BLE Connector",
    "passiveScanMode": true,
    "showMap": false,
    "scanner": {
        "timeout": 10000,
        "deviceName": "STH11"
    },
    "devices": [
        {
            "name": "Temperature and humidity sensor",
            "MACAddress": "4C:65:A8:DF:85:C0",
            "pollPeriod": 5000,
            "showMap": false,
            "timeout": 10000,
            "telemetry": [
                {
                    "key": "temperature",
                    "method": "notify",
                    "characteristicUUID": "226CAA55-6476-4566-7562-66734470666D",
                    "valueExpression": "[2]"
                },
                {
                    "key": "humidity",
                    "method": "notify",
                    "characteristicUUID": "226CAA55-6476-4566-7562-66734470666D",
                    "valueExpression": "[:]"
                }
            ],
            "attributes": [
                {
                    "key": "name",
                    "characteristicUUID": "00002A00-0000-1000-8000-00805F9B34FB",
                    "method": "read",
                    "valueExpression": "[0:2]"
                }
            ],
            "attributeUpdates": [
                {
                    "attributeOnThingsBoard": "sharedName",
                    "characteristicUUID": "00002A00-0000-1000-8000-00805F9B34FB"
                }
            ],
            "serverSideRpc": [
                {
                    "methodRPC": "sharedName",
                    "withResponse": true,
                    "characteristicUUID": "00002A00-0000-1000-8000-00805F9B34FB",
                    "methodProcessing": "write"
                }
            ]
        }
    ]
}

To understand how this connector works, we will describe how to connect device Xiaomi Mi Smart Temperature Humidity Sensor to ThingsBoard using gateway. We know following device parameters: Device MAC address - 4C:65:A8:DF:85:C0 Default name characteristic id - 00002A00-0000-1000-8000-00805F9B34FB - This is a default characteristic - we have got it ID from GATT characeristics documentation Temperature characteristic id - 00002A00-0000-1000-8000-00805F9B34FB - This is a custom characteristic - we have got it after scanning device characteristics.

Default configuration created for this device to process data from it, receive notifies and write some information.

In a main section we write general configuration for our connector, such as connector name, scan mode, scanner, etc.
In a device subsection we write general configuration for connection to our device (name for device in ThingsBoard and device MAC address, etc.).
In a subsection telemetry we write the configuration for processing data from the device (Where the gateway should take the data, method and converter will interpret this data to telemetry and attributes on ThingsBoard).
In a subsection attributeUpdates we write the configuration to rename the device after receiving attribute update request from ThingsBoard.
If device shared attribute with a name “sharedName” changed - gateway will write data from this attribute to characteristic with ID - 00002A00-0000-1000-8000-00805F9B34FB.

Main section

This section contains general settings for the connector.

This part of configuration will look like:

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{
    "name": "BLE Connector",
    "passiveScanMode": true,
    "showMap": false,
    "scanner": {
        "timeout": 10000,
        "deviceName": "NH11"
    },
    "devices": [
        ...
    ]
}

Also let’s take a look at methods for discovering available devices. For this we will use two different scenarios.

1. First Scenario

   In the first scenario we have to configure BLE Connector for displaing all finded devices because we don’t know MAC address of our device and his name too. For this we have to use the next configuration:

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   {
       ...
       "showMap": true
       ...
   }
   

   Gateway output:

   24:71:89:cc:09:05 - NH11

   54:bb:12:ff:09:01 - Unknown

   23:cc:34:23:bb:56 - XYZ123

2. Second Scenario

   In the second scenario we know Bluetooth displaing device name and want to know only his MAC address. For this we have to use the next configuration:

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   {
       ...
       "showMap": true,
       "scanner": {
           "timeout": 10000,
           "deviceName": "NH11"
       }
       ...
   }
   

   Gateway output:

   24:71:89:cc:09:05 - NH11

Device object subsection

This subsection contains general settings for the device and subsections for processing data.

This part of configuration will look like:

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{
    "name": "Temperature and humidity sensor",
    "MACAddress": "4C:65:A8:DF:85:C0",
    "showMap": true,
    "pollPeriod": 5000,
    "timeout": 10000,
    "telemetry": [
        ...
    ],
    "attributes": [
        ...
    ],
    "attributeUpdates": [
        ...
    ],
    "serverSideRpc": [
        ...
    ]
}

Subsection telemetry

This subsection contains general settings for the processing data interpreted as telemetry.

This part of configuration will look like:

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{
    "key": "temperature",
    "method": "notify",
    "characteristicUUID": "226CAA55-6476-4566-7562-66734470666D",
    "valueExpression": "[0:1]"
},

The values shown in the table above may differ in your configuration.

For example response from device is bytes array like b’\x08<\x08\x00’, in this case – 8 interpreted as value of key.

If you need to interpreted full response as value use “valueExpression”: “[:]”.

You can find more examples of data converting in section “Examples of data converting”.

Subsection attributes

This subsection contains general settings for the processing data interpreted as attributes.

This part of configuration will look like:

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{
    "key": "name",
    "characteristicUUID": "00002A00-0000-1000-8000-00805F9B34FB",
    "method": "read",
    "valueExpression": "[0:1] cm"
}

The values shown in the table above may differ in your configuration.

For example response from device is bytes string like b’\x08<\x08\x00’, in this case – 8 cm interpreted as value of key.

If you need to interpreted full response as value use “valueExpression”: “[:]”.

You can find more examples of data converting in section “Examples of data converting”.

Services and characteristics, from GATT Specification will also interpret as attributes of device and automatically loaded to ThingsBoard.

Examples of data converting

Let’s review more examples of data converting:

Basic scenario: we have a device that measures temperature and humidity. Device has charasteristic that can be read and when we receive data from her, the data combine temperature and humidity. So, data from device have the next view: b’\x08<\x08\x00’ and in human readable format: [8, 34] (first array element is temperature and the second is humidity).

1. We want to read only temperature value

   “valueExpression”: “[0]”

   Data to ThingsBoard:8

2. We want to read only humidity value

   “valueExpression”: “[1]”

   Data to ThingsBoard:34

3. We want to read all values

   “valueExpression”: “[:]” or “valueExpression”: “[0:2]”

   Data to ThingsBoard: 834

4. We want to read all values and dimensional units

   “valueExpression”: “[0]°C [1]%”

   Data to ThingsBoard: 8°C 34%

Subsection attributeUpdates

This subsection contains settings for the processing attributeUpdate requests from ThingsBoard.

This part of configuration will look like:

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{
    "attributeOnThingsBoard": "sharedName",
    "characteristicUUID": "00002A00-0000-1000-8000-00805F9B34FB"
}

Characteristic should support method WRITE for processing the attributeUpdate request.

Subsection serverSideRpc

This subsection contains settings for the processing RPC requests from ThingsBoard.

This part of configuration will look like:

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{
    "methodRPC": "rpcMethod1",
    "withResponse": true,
    "characteristicUUID": "00002A00-0000-1000-8000-00805F9B34FB",
    "methodProcessing": "read"
}

Next steps

Explore guides related to main ThingsBoard features:

• Connect BLE sensor - how to connect BLE sensor using ThingsBoard IoT Gateway
• Data Visualization - how to visualize collected data.
• Device attributes - how to use device attributes.
• Telemetry data collection - how to collect telemetry data.
• Using RPC capabilities - how to send commands to/from devices.
• Rule Engine - how to use rule engine to analyze data from devices.