Azure IoT Central: JSON format for IOT device gateway when forwarding messages.

Question

Hi.

In my Azure Iot Central I want to display information from devices that do not have IP capabilities. They are however connected to a device that have IP capabilities. What I am unable to find is on what format a custom IoT Device Gateway should forward messages from other devices. Example scenario:

Azure IoT Device Gateway: fooForwarder
IoT device: sensor1
IoT device: sensor2
IoT device: sensor3

sensor1 -> [Data] -->\
sensor2 -> [Data] -->-- fooForwarder -> Azure IoT Central
sensor1 -> [Data] -->/

I want to be able to display the data from my sensors by using fooForwarder. I have tried looking at the documentation but it does not say anything about the format. I have read the doc below and the ones that this doc links too. But have been unable to find the JSON format on which the gateway should use to forward messages to the Azure IoT Central.

https://learn.microsoft.com/en-us/azure/iot-central/core/tutorial-define-gateway-device-type

I might have misunderstood some concepts completely in that case please inform me :)

Best regards,
Oliver

Answer 1

Hello @Oliver O ,

there are multiple approaches to make this work.

It all begins with the FooForwarder. This is a device that is connected to IoT Central. This can be as much as an ESP or even an Azure IoT Edge device (like a Raspberry Pi).

The messages sent by that forwarder will be picked up by IoT Central and eg. shown in a dashboard.

It's unclear how the communication between the FooForwarder and the three IoT devices is done (are these actual other devices or just three (analog?/digital?) sensors).

It's up to you to read telemetry from the sensors so the values can be sent to the cloud.

There are multiple SDKs available to program your direct internet-connected device or edge device so it can connect to IoT Central.

Note: The IoT Edge solution has a child device concept. This is for child devices that are capable to act as direct internet-connected devices.

The tutorial you refer to is not the easiest part to start with. Please check out the IoT Central modules and IoT edge modules first.