BLE Connector Configuration

• Main section
  • Device object subsection
    • Subsection telemetry
    • Subsection attributes
    • Subsection attributeUpdates
    • Subsection serverSideRpc
• Next steps

This guide will help you to get familiar with BLE connector configuration for NDU 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 bluepy

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sudo yum groupinstall -y "development tools"

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sudo pip3 install bluepy

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{
    "name": "BLE Connector",
    "rescanIntervalSeconds": 100,
    "checkIntervalSeconds": 100,
    "scanTimeSeconds": 5,
    "passiveScanMode": true,
    "devices": [
        {
            "name": "Temperature and humidity sensor",
            "MACAddress": "4C:65:A8:DF:85:C0",
            "telemetry": [
                {
                    "key": "temperature",
                    "method": "notify",
                    "characteristicUUID": "226CAA55-6476-4566-7562-66734470666D",
                    "byteFrom": 2,
                    "byteTo": 6
                },
                {
                    "key": "humidity",
                    "method": "notify",
                    "characteristicUUID": "226CAA55-6476-4566-7562-66734470666D",
                    "byteFrom": 9,
                    "byteTo": 13
                }
            ],
            "attributes": [
                {
                    "key": "name",
                    "characteristicUUID": "00002A00-0000-1000-8000-00805F9B34FB",
                    "method": "read",
                    "byteFrom": 0,
                    "byteTo": -1
                }
            ],
            "attributeUpdates": [
                {
                    "attributeOnNDU": "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 NDU 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 interval, etc.
In a device subsection we write general configuration for connection to our device (name for device in NDU 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 NDU).
In a subsection attributeUpdates we write the configuration to rename the device after receiving attribute update request from NDU.
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",
    "rescanIntervalSeconds": 100,
    "checkIntervalSeconds": 100,
    "scanTimeSeconds": 5,
    "passiveScanMode": true,
    "devices": [
                ...
                ]
}

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",
            "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",
                    "byteFrom": 2,
                    "byteTo": 6
                },

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

** – For example response from device is bytes string like b’T=54.7 H=37.0’, in this case – 54.7 interpreted as value of key.

If you need to interpreted full response as value use byteFrom: 0 and byteTo: -1.

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",
                    "byteFrom": 0,
                    "byteTo": -1
                }

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

** – For example response from device is bytes string like b’Coolest device’, in this case – Coolest device interpreted as value of key.

If you need to interpreted full response as value use byteFrom: 0 and byteTo: -1.

Subsection attributeUpdates

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

This part of configuration will look like:

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

Subsection serverSideRpc

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

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 NDU features:

• Connect BLE sensor - how to connect BLE sensor using NDU 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.