On Atwood's Law and Control Systems

Example usage of µRDF.js in a building automation application.

System Components

Servients (system components):

• thermostat.local
• temp-sensor.local
• contact-sensor.local
• humidity-sensor.local
• light-sensor.local
• blinds.local
• light-bulb.local
• energy-meter.local
• beamer.local

            
{
    "@context": "https://www.w3.org/2019/wot/td/v1",
    "id": "tag:thermostat",
    "title": "Radiator thermostat",
    "properties": {
        "setpoint": {
            "type": "number",
            "forms": [
                {
                    "href": "https://thermostat.local/setpoint",
                    "op": [ "readproperty", "writeproperty" ]
                }
            ]
        }
    }
}
            
        

            
{
    "@context": "https://www.w3.org/2019/wot/td/v1",
    "id": "tag:temp-sensor",
    "title": "Temperature sensor",
    "properties": {
        "val": {
            "type": "number",
            "forms": [
                {
                    "href": "https://temp-sensor.local/val",
                    "op": [ "readproperty" ]
                }
            ]
        }
    }
}
            
        

            
{
    "@context": "https://www.w3.org/2019/wot/td/v1",
    "id": "tag:contact-sensor",
    "title": "Contact sensor (window)",
    "events": {
        "change": {
            "data": {
                "type": "boolean"
            },
            "forms": [
                {
                    "href": "https://contact-sensor.local/change",
                    "op": [ "subscribeevent" ]
                }
            ]
        }
    }
}
            
        

            
{
    "@context": "https://www.w3.org/2019/wot/td/v1",
    "id": "tag:humidity-sensor",
    "title": "Humidity sensor",
    "properties": {
        "val": {
            "type": "number",
            "forms": [
                {
                    "href": "https://humidity-sensor.local/val",
                    "op": [ "readproperty" ]
                }
            ]
        }
    }
}
            
        

            
{
    "@context": "https://www.w3.org/2019/wot/td/v1",
    "id": "tag:light-sensor",
    "title": "Brightness sensor",
    "properties": {
        "val": {
            "type": "number",
            "forms": [
                {
                    "href": "https://light-sensor.local/val",
                    "op": [ "readproperty" ]
                }
            ]
        }
    }
}
            
        

            
{
    "@context": "https://www.w3.org/2019/wot/td/v1",
    "id": "tag:blinds",
    "title": "Window blinds",
    "actions": {
        "open": {
            "input": {
                "type": "boolean"
            },
            "forms": [
                {
                    "href": "https://blinds.local/open",
                    "op": [ "invokeaction" ]
                }
            ]
        }
    }
}
            
        

            
{
    "@context": "https://www.w3.org/2019/wot/td/v1",
    "id": "tag:light-bulb",
    "title": "Light bulb",
    "actions": {
        "turnOn": {
            "input": {
                "type": "boolean"
            },
            "forms": [
                {
                    "href": "https://light-bulb.local/turnOn",
                    "op": [ "invokeaction" ]
                }
            ]
        }
    }
}
            
        

            
{
    "@context": "https://www.w3.org/2019/wot/td/v1",
    "id": "tag:energy-meter",
    "title": "Energy meter",
    "properties": {
        "reading": {
            "type": "number",
            "forms": [
                {
                    "href": "https://energy-meter.local/reading",
                    "op": [ "readproperty" ]
                }
            ]
        }
    }
}
            
        

            
{
    "@context": "https://www.w3.org/2019/wot/td/v1",
    "id": "tag:tv",
    "title": "Television",
    "properties": {
        "status": {
            "type": "boolean",
            "forms": [
                {
                    "href": "https://television.local/status",
                    "op": [ "readproperty" ]
                }
            ]
        },
        "contrast": {
            "type": "number",
            "forms": [
                {
                    "href": "https://television.local/contrast",
                    "op": [ "readproperty", "writeproperty" ]
                }
            ]
        }
    }
}
            
        

Semantic Relations

            
{
    "@d": "tag:conference-room",
    "bot:hasElement": [
      "tag:temp-sensor",
      "tag:contact-sensor"
    ]
}
            
        

            
{
    "@d": "tag:conference-room",
    "bot:hasElement": [
      "tag:temp-sensor",
      "tag:thermostat"
    ]
}
            
        

            
{
    "@d": "tag:conference-room",
    "bot:hasElement": [
      "tag:thermostat",
      "tag:contact-sensor"
    ]
}
            
        

This tutorial was first presented as a poster at the 1st Franconian Workshop on Data Spaces and the IoT (DSIoT 2019).