Simple RESTful sensor application development model using CoAP

Gateway or cloud based interaction models are widely used for automation solutions that use networked sensors and actuators. In this model, every sensor/actuator interaction goes through the gateway or via the cloud. In order to realize the true Internet of Things philosophy where everything is interconnected, direct interactions between sensors and actuators, also called bindings, are important. In addition to this, alternative IoT application development models which facilitate application development and improve efficiency are required. In this paper, we first introduce a CoAP based sensor/actuator binding solution where a 3rd party is responsible for setting up the binding, but is not involved in any of the further interactions. Next, the binding concept is extended to introduce (pre-)processing into the sensor/actuator interactions in the form of RESTlets. RESTlets are small application building blocks with internal processing logic and RESTful interfaces for input, control and output. Finally, we present how IoT applications can be created by binding different RESTlets to each other and to sensors and actuators.