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Smart objectapi tutorial 092013
The document introduces the IoT Toolkit and Smart Object API, which provide an open-source framework for building Internet of Things applications and enabling interoperability between IoT devices and platforms. The toolkit includes a reference implementation of the Smart Object API that defines a REST API and data models for representing IoT objects and their properties. It allows IoT applications to access sensor data and control devices through a common interface.
Smart objectapi tutorial 092013
- 1. IoT Toolkit and Smart Object API Tutorial Introduc7on Open Source Internet of Things
- 2. IoT 2.0 – Interoperability M2M CoAP M2M MQ SOA M2M HTTP Smart Object API IoT Toolkit Discovery Applica7ons Thing Models Resource Models • Object Model • REST + Event Model • M2M Abstrac<ons IoT Toolkit Connected Things, Sensors, Actuators, Data Sources Seman5c Repository • Easy to deploy new things and applica7ons using data models • Write once run anywhere, any app to any thing via any M2M • Network effect enabled • Allows for appropriate M2M choice
- 3. Interoperability Architecture SO SO SO Gateway Server Cloud Endpoints • Sensors • Devices Applica7on Components And Resources Databases Instances Classes SRT • Discovery • Persistence • Replica7on • Resource Access • Data Models • Sensor Models • Machine Models • Templates
- 4. IoT Toolkit • IoT Toolkit is a reference implementa7on of the Smart Object API and related tools • REST API with real-‐7me event model for the Internet of Things • Lightweight server that can run on small computers e.g. Raspberry Pi • Work in progress prototype (limited excep7on handling and simple interfaces)
- 5. Smart Object API • Object Model – Web Object Encapsula7on • Data Models – Linked Data descrip7ons • Event Model – Asynchronous M2M and applica7on soUware event handlers • REST API using JSON, XML, RDF representa7ons • Web standards and best prac7ces with new extensions
- 6. Object Model Web Object Encapsula7on Smart Object Web protocol interfaces, also M2M e.g. MQTT Event Model Links data with ac7ons Pub-‐Sub and event handlers Encapsulates local soUware components and handlers Self-‐describing data model For Resource Discovery and Linkage Sensor or other data JSON, XML, data feeds
- 7. Smart Object Structure – Object Model Smart Object Descrip7on ObservableProperty ObservableProperty… Agent Publisher Subscriber Handler PropertyOfInterest Descrip7on Observers Handler Instance Daemon Default Property
- 8. REST API • Python API – Local SoUware, Agents and Handlers – Resources (objects) are hierarchical proper7es of other resources – self.indoorTempValue = sensors.weather.indoor_temp.get()! • Web API – HYp REST Client access – Resources are organized in hierarchical path – GET http:my_server:8000/sensors/weather/indoor_temp! • Default Property – Returns a resource associated with a higher level resource – GET of Smart Object returns it’s Descrip7on; GET of Observable Property returns it’s Observa7on Value
- 9. API – Descrip7on (Data Model) • Contains graphs describing the resource data model • RDF in many popular representa7ons – create (POST) loads a graph into the descrip7on delete (DELETE) removes a graph or subgraph from the descrip7on – set (PUT) updates a graph or subgraph – get (GET) returns a graph or subgraph
- 10. API – Observable Property • Represents sensor data or a data feed • Can be JSON, xml, text, or other content type – create (POST): make new observable property – delete (DELETE) remove observable property – set (PUT) update Observa7on Value or data feed – get (GET) returns the current Observa7on Value
- 11. API – Observers • Contains graphs which define endpoints of event driven processing • Publish, Subscribe, and Event Handler paYerns • Reference Implementa7on – create (POST) makes a new Observer • Publisher, Subscriber, or Handler Class – set (PUT) updates an Observer’s seangs – get (GET) returns an Observer’s seangs – delete (DELETE) removes an observer graph
- 12. API – Agent • Container for Event Handlers, soUware components invoked within the local context of the Smart Object • Observer class invokes Event Handler code • Reference Implementa7on – create (POST) makes a new code object instance • type handler or daemon – delete (DELETE) removes code instance – set (PUT) updates seangs of a code instance – get (GET) returns seangs of a code instance
- 13. Weather Sensor Example • Weather Sensor hardware from Sparkfun • Arduino connects hardware sensors to gateway via ethernet • Raspberry Pi gateway runs Smart Object API • Arduino uses hYp POST of JSON value to update Smart Object Observable Proper7es • Smart Object built using python code
- 14. Weather sensor example Sensor (Arduino) Gateway (Rpi) Sensor Hardware • Wind Speed • Wind Direc7on • Rainfall • Temperature • Humidity • Barometer Reads sensor elements and creates sensor output values to update Smart Object in the Gateway using a simple hYp client Gateway runs Smart Object API and exposes HTTP interface, adds descrip7onand other resources, Observers send updates to cloud server Local Ethernet Cloud Server acts as Gateway-‐as-‐a-‐Service for Xively Receives updates from the gateway, Observers Send periodic updates to Xively feed Cloud Server Internet Client (Xively) Internet Xively acts as client applica7on and receives updates from the cloud service ac7ng as GaaS
- 15. Arduino Sketch PString jsonObject(objectBuffer, sizeof(objectBuffer));! ! if(nextPushPoint==0) {! nextPushPoint=1;! /* use Pstring.print to format JSON string from integer */! jsonObject.println(daily_rain,1); ! /* PUT update to Smart Object server property using JSON */! client.print("PUT ");! client.print(serverPath);! client.print(”daily_rain");! client.println(" HTTP/1.1");! client.println("Content-Type: application/json");! client.print("Content-Length: ");! client.println(jsonObject.length()-2);! client.println("Connection: close");! client.println();! client.println(jsonObject);! }!
- 16. Demo Code for Weather Sensor – Smart Object and Service Crea7on baseObject = SmartObject() # create a Smart Object to serve as the base container for other Smart Objects and resources server = SmartObjectService(baseObject) # make an instance of the service, baseObject is the object root server.start(8000) # forks a server thread to listen on port 8000 print 'hDpd started at', baseObject.Proper<es.get('hDpService’) # top level object container for sensors, class is SmartObject sensors = baseObject.create({'resourceName': 'sensors', 'resourceClass': 'SmartObject'}) #weather sensor Smart Object under sensors for the weather sensor weather = sensors.create({'resourceName': 'rhvWeather-‐01', 'resourceClass': 'SmartObject’}!
- 17. Data Model – Descrip7on for object discovery and linkage # make a reference to the weather sensor object Descrip7on and build an example graph (could use the built-‐in reference as well) weather.descrip7on = weather.Resources.get('Descrip<on') weather.descrip7on.set((URIRef('sensors/rhvWeather-‐01/outdoor_temperature'), RDFS.Resource, Literal('sensor'))) weather.descrip7on.set((URIRef('sensors/rhvWeather-‐01/outdoor_temperature'), RDF.type, Literal('temperature'))) weather.descrip7on.set((URIRef('sensors/rhvWeather-‐01/outdoor_humidity'), RDFS.Resource, Literal('sensor'))) weather.descrip7on.set((URIRef('sensors/rhvWeather-‐01/outdoor_humidity'), RDF.type, Literal('humidity'))) weather.descrip7on.set((URIRef('sensors/rhvWeather-‐01/sealevel_pressure'), RDFS.Resource, Literal('sensor'))) weather.descrip7on.set((URIRef('sensors/rhvWeather-‐01/sealevel_pressure'), RDF.type, Literal('pressure')))!
- 18. Encapsula7on: Observable Property, Observer, and Subscriber sealevel_pressure = weather.create({'resourceName': 'sealevel_pressure', 'resourceClass': 'ObservableProperty'}) sealevel_pressure.Observers.create({'resourceName':'demoServiceObserver', 'resourceClass': 'hDpPublisher', 'targetURI': 'hDp://smartobjectservice.com: 8000/sensors/rhvWeather-‐01/sealevel_pressure'}) # make a named subscriber resource outdoor_humidity.Observers.create({'resourceName': 'humiditySubscriber', 'resourceClass': 'hDpSubscriber', 'observerURI': 'hDp://localhost:8000/sensors/rhvWeather-‐01/ indoor_humidity', 'observerName': 'humiditySubObserver' })
- 19. Event Model – Xively Publisher -‐ Observer sealevel_pressure.Observers.create({'resourceName': 'xivelyObserver', 'resourceClass': 'xivelyPublisher', 'apiBase': 'hDps://api.xively.com/v2/feeds', 'feedID': '2141862995', 'streamID': 'sealevel_pressure’, 'apiKey’:'QYourApiKeyGoesHEresjhgrjgo56', 'updateInterval': pushInterval })
- 20. Event Model – Handler and Callback No7fier #addHandler class adds 2 proper7es values together and stores in a third weather.Agent.create({'resourceName': 'addHandler', 'resourceClass': 'addHandler', 'addendLink1':'sensors/rhvWeather-‐01/indoor_temperature', 'addendLink2': 'sensors/rhvWeather-‐01/indoor_temperature', 'sumOutLink': 'sensors/rhvWeather-‐01/outdoor_humidity'}) # now create a callback observer endpoint indoor_temperature.Observers.create({'resourceName': 'callbackTempObserver', 'resourceClass': 'callbackNo<fier', 'handlerURI': 'callback:///sensors/rhvWeather-‐01/Agent/ addHandler'})
- 21. IoT Toolkit Project • Smart Object API is nominally complete and stable • Development priori7es – Web UI for debug and demo, simple applica7ons • Navigator, Dashboard, Analy7cs, Graphs and Charts – M2M Endpoints for CoAP, MQTT, and others – Test code for API – Internal features development • Build SmartObject Instances from Resource Models • Object Persistence • Data persistence and storage
- 22. MQTT Observer • Publish, Subscribe, or Pub+Sub using the mqYObserver resource class • Prototype opens a connec7on to a specified broker for each endpoint Observers.create({'resourceName': 'mqttTestObserver',! ! ! ! ! ! 'resourceClass': 'mqttObserver',! 'connection': 'smartobjectservice.com',! 'pubTopic': ’sealevel_pressure',! 'subTopic': None,! 'QoS': 0,! 'keepAlive': 60 })!
- 23. MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Connects REST Resource to MQTT Topic Publish and Subscribe
- 24. MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Publisher Publishes REST Resource updates to the broker
- 25. MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Subscriber Makes last published data available at the REST endpoint
- 26. MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Pub+Sub Repeats data updates in both direc7ons
- 27. MQTT Bridge to mul7ple REST endpoints MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish to Other Subscribers REST Endpoint ObservableProperty mqYObserver PUT GET