IoT Cloud: AWS "Device Shadows", Azure "Device Twins"

Device Shadows for AWS IoT - AWS IoT

"A thing shadow (sometimes referred to as a device shadow) is a JSON document that is used to store and retrieve current state information for a thing (device, app, and so on). The Thing Shadows service maintains a thing shadow for each thing you connect to AWS IoT. You can use thing shadows to get and set the state of a thing over MQTT or HTTP, regardless of whether the thing is connected to the Internet. Each thing shadow is uniquely identified by its name."

Device Shadows Documents - AWS IoT

{

    "state" : {

        "desired" : {

          "color" : "RED",

          "sequence" : [ "RED", "GREEN", "BLUE" ]

        },

        "reported" : {

          "color" : "GREEN"

        }

    },

    "metadata" : {

        "desired" : {

            "color" : {

                "timestamp" : 12345

            },

            "sequence" : {

                "timestamp" : 12345

            }

        },

        "reported" : {

            "color" : {

                "timestamp" : 12345

            }

        }

    },

    "version" : 10,

    "clientToken" : "UniqueClientToken",

    "timestamp": 123456789

}

Managing Things with AWS IoT - AWS IoT

"AWS IoT provides a thing registry that helps you manage your things. A thing is a representation of a specific device or logical entity. It can be a physical device or sensor (for example, a light bulb or a switch on a wall). It can also be a logical entity like an instance of an application or physical entity that does not connect to AWS IoT but is related to other devices that do (for example, a car that has engine sensors or a control panel)."

{

    "version": 3, 

    "thingName": "MyLightBulb", 

    "defaultClientId": "MyLightBulb", 

    "thingTypeName": "LightBulb", 

    "attributes": {

        "model": "123", 

        "wattage": "75"

    }

}

Managing Things with the Thing Registry - AWS IoT

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Get started with Azure IoT Hub device twins (Node) | Microsoft Docs

"Device twins are JSON documents that store device state information (metadata, configurations, and conditions). IoT Hub persists a device twin for each device that you connect to IoT Hub."

Device management with Azure IoT Hub | Microsoft Docs





Understand the Azure IoT Hub query language | Microsoft Docs