Properly Create a Device Template from a Live Device in Azure IOT Central - azure-iot-central

Question

I have LoRaWAN IoT devices from the TTN network, which I have brought to Azure IoT Central. I would like to get specific data inside the JSON in order to make alert rules. Here is a sample of the JSON I receive from a Milesight PIR & Light Sensor. Suppose I only want to get the "battery", "daylight" and "pir" values to make the alert, how do I go about that?
{
"end_device_ids": {
"device_id": "eui-24e124538c195063",
"application_ids": {
"application_id": "test-1117"
},
"dev_eui": "24E124538C195063",
"join_eui": "24E124C0002A0001",
"dev_addr": "260D82F3"
},
"received_at": "2023-02-01T13:52:47.892042526Z",
"uplink_message": {
"session_key_id": "AYYLj9wg6AeehHWwDLrzLg==",
"f_port": 85,
"f_cnt": 38,
"frm_payload": "AXVkAwAABAAA",
"decoded_payload": {
"battery": 100,
"daylight": "dark",
"pir": "normal"
},
"rx_metadata": [
{
"gateway_ids": {
"gateway_id": "eui-24e124fffef5531c",
"eui": "24E124FFFEF5531C"
},
"time": "2023-02-01T13:52:47.429725885Z",
"timestamp": 2696081442,
"rssi": -64,
"channel_rssi": -64,
"snr": 13,
"uplink_token": "CiIKIAoUZXVpLTI0ZTEyNGZmZmVmNTUzMWMSCCThJP/+9VMcEKLgy4UKGgwIr93pngYQ94rGxQIg0Ino17uJFw==",
"received_at": "2023-02-01T13:52:47.596682842Z"
}
],
"settings": {
"data_rate": {
"lora": {
"bandwidth": 125000,
"spreading_factor": 7,
"coding_rate": "4/5"
}
},
"frequency": "867700000",
"timestamp": 2696081442,
"time": "2023-02-01T13:52:47.429725885Z"
},
"received_at": "2023-02-01T13:52:47.683989041Z",
"confirmed": true,
"consumed_airtime": "0.061696s",
"network_ids": {
"net_id": "000013",
"tenant_id": "ttn",
"cluster_id": "au1",
"cluster_address": "au1.cloud.thethings.network"
}
},
"_eventtype": "Telemetry",
"_timestamp": "2023-02-01T13:52:49.35Z"
}

Answer 1

I was able to get the values by uploading my own DTDL.
Once the device sends data to Azure IOT Central from TTN, the device will have no template.
I first created a template from the raw telemetry sent.
I went to the new device template created, clicked EDIT DTDL, then placed the following JSON:
{
"#id": "dtmi:telavi:eui24e124538c195063;1",
"#type": "Interface",
"contents": [
{
"#type": [
"Telemetry",
"DateTimeValue"
],
"displayName": {
"en": "received_at"
},
"name": "received_at",
"schema": "dateTime"
},
{
"#type": [
"Telemetry",
"NumberValue"
],
"description": {
"en": "battery"
},
"displayName": {
"en": "battery"
},
"name": "battery",
"schema": "integer"
},
{
"#type": [
"Telemetry",
"StringValue"
],
"description": {
"en": "daylight"
},
"displayName": {
"en": "daylight"
},
"name": "daylight",
"schema": "string"
},
{
"#type": [
"Telemetry",
"StringValue"
],
"description": {
"en": "pir"
},
"displayName": {
"en": "pir"
},
"name": "pir",
"schema": "string"
}
],
"displayName": {
"en": "eui-24e124538c195063"
},
"#context": [
"dtmi:iotcentral:context;2",
"dtmi:dtdl:context;2"
]
}