Data Telemetry from BLE Devices

Registering Topics

Register Topics - API Definition

API

Description

 
/control/registration/registerTopic

This API registers the topic with the gateway to subscribe to GATT notifications from device using ID, service UUID, and characteristic UUID.

The subscriptions can be placed to various GATT attributes:

  • Blood Oxygen level

  • Heart rate

  • Walking rate

API Example - Register Topics

Register Topics Request:


{
"technology": "ble",
"ids": [
"df553860-975c-4d7f-8c1f-b2996f34e26f",
],
"controlApp": "controlApplication",
"topic": "enterprise/hospital/pulse_oximeter",
"dataFormat": "default",
"ble": {
"type": "gatt",
"serviceID": "1800",
"characteristicID": "2A5E"
}
}

Register Topics Response:


{
    "status": "SUCCESS",
    "topic": "enterprise/hospital/pulse_oximeter",
    "reason": "Gatt topics successfully registered!"
}

Telemetry Message Format

The telemetry messages are in protobuf format. All the telemetry messages are encapsulated in the DataSubscription message.

Subscribing to Advertisements and Notifications

Subscribing to Advertisements and Notifications - API Definition

API

Description

 
/control/data/subscribe

Use this API to enable GATT notifications or indications in the BLE device using the device ID, GATT service UUID, and characteristic UUID.

API Example – Subscribing to Advertisements and Notifications

Request:


{
"technology": "ble",
"id": "df553860-975c-4d7f-8c1f-b2996f34e26f",
"ble": {
"serviceID": "1800",
"characteristicID": "2A5E"
},
"controlApp": "controlApplication"
}

Response:


{
"status": "SUCCESS",
"id": "df553860-975c-4d7f-8c1f-b2996f34e26f",
"requestID": "12345678-5678-1234-5578-abcdef1234"
}

MQTT Subscription Messages

Once the notification is enabled using the subscribe API, the data receiver application starts to receive the GATT notification. To receive the notification, you will need to execute the following command in your terminal session: 


mosquitto_sub -h localhost -p 41883 -t 
enterprise/hospital/pulse_oximeter -u
https://dataApplication --pw 
c4e80e0483af0a4394dfb6e3ec5e820b

Telemetry Message Format for Onboarded Advertisements and Notifications

The following is the code snippet of Telemetry message format:


syntax = "proto3";

import "google/protobuf/timestamp.proto";

option java_package = "org.ietf.nipc.proto";
option java_multiple_files = true;

package nipc;

message DataSubscription {
    optional string device_id = 1;
    bytes data = 2;
    google.protobuf.Timestamp timestamp = 3;
    optional string ap_mac_address = 4;

    reserved 5 to 10;

    oneof subscription {
        BLESubscription ble_subscription = 11;
        BLEAdvertisement ble_advertisement = 12;
        RawPayload raw_payload = 14;
        BLEConnectionStatus ble_connection_status = 15;
    }

    message BLESubscription {
        optional string service_uuid = 1;
        optional string characteristic_uuid = 2;
    }

    message BLEAdvertisement {
        string mac_address = 1;
        optional int32 rssi = 2;
    }

    message BLEConnectionStatus {
        string mac_address = 1;
        bool connected = 2;
        optional int32 reason = 3;
    }
    
    message RawPayload {
        optional string context_id = 1;
    }
}