The system consists of 2 interconnected networks: the first network, formed by the Sparrow nodes, is connected to an external network through a border router. Once data reaches the external network, it can be stored in a database and/or sent to user devices.

One of the Sparrow nodes is chosen to be the border router that communicates with a host using a tool called tunslip6. Tunslip6 creates a virtual network interface(tun0) and uses SLIP (Serial Line Internet Protocol) to encapsulate the traffic on the serial line. The border router will receive the address aaaa::1 and it will form a network with the other Sparrow nodes, by passing the prefix received from the host to all nodes.

The other Sparrow nodes will run Contiki with a CoAP server as the main application. Those nodes will acquire data using different sensors and will pass the data to the CoAP client in the external network. Since CoAP is based on the REST model, obtaining data from the nodes using CoAP is similar to performing HTTP requests. The general syntax for making such a request looks like this:

coapclient -o REQUEST -p PATH

where “REQUEST” can be one of the following: GET|PUT|POST|DELETE|DISCOVER|OBSERVE and PATH is the path where the resource is found on the server. For example, here is a command that requests the temperature value from the server:

coapclient -o GET -p coap://[aaaa::11:22:33:44]:5683/sensors/temperature

The data received by the CoAP client can be stored in a cloud database, to be accessible from anywhere, at anytime.