Node-RED
- 1. A visual tool for wiring the internet of things David Ghedalia
- 2. Flow-based programming • An application constits of a set of blocks • The programmer treats each block as a blackbox • Knowing the implementation details is not necessary • Each block has one or more ports (in input, output or both) to communicate with other blocks • The communication is message-based
- 3. IoT and visual programming The very nature of flow-based programming leads to two major consequences: • It can be easily implemented in a visual manner, allowing the development of complex applications in a short period of time • Pardigm is particularly suitable for an IoT environment, in which a large amount of computation is used to exchange messages
- 4. What is Node-RED? • Node-RED is a flow-based development tool developed originally by IBM for wiring together hardware devices, APIs and online services as part of the Internet of Things • Thanks to its intuitive browser-based flow editor, Node-RED gives the possibility to build applications even to non programmers
- 5. The architecture • Runtime It is written in Javascript and based on NodeJS, taking full advantage of its event-driven, non-blocking model • UI Written in HTML and JavaScript: it enables to build flows in a visual manner
- 6. Other features • Node-RED is open source • Simple and fast to deploy • Flows stored as a JSON file In this way, they can be easily shared • Thousands of custom nodes (and flows) built by the community
- 8. Launching Node-RED • After the installation (requires NodeJS), open the command prompt and digit: «node-red» • To access the editor, open the browser and go to localhost at port 1880
- 9. Building the first flow (1) In the main page of Node-RED, there are three major sections Node palette on the left • At first, it will contain the core nodes only • The nodes are organized in categories The main work space on the center Output pane on the right • Useful for getting info about the selected node • Here you can find the debug section
- 10. Building the first flow (2) • To insert a node in the current flow, drag a node from the palette and drop it into the workspace • To edit a node, double-click on it: a pane will appear, containing all the editable settings. In certain nodes, one or more fields will be required before being able to deploy the flow • To link two nodes, click and hold the output port of the first node and release at the input port of the second node
- 11. Building the first flow (3) • Click deploy to make the flow run
- 12. The project
- 13. Description home/switchLed home/ledStatus MQTT client MQTT client + MQTT broker NodeMCU Raspberry Pi • NodeMCU acts as an MQTT client: it subscribes to topic «home/switchLed» and publishes to topic «home/ledStatus» • Raspberry Pi is both an MQTT client and MQTT broker. NodeRED will provide: A graphical interface to switch the led on and off (running at localhost:1880/ui/) A log file that will be updated each time that the led is turned on or off• HTTP HTTP
- 14. Flow
- 15. Flow (1)
- 16. Flow (2)
- 18. MQTT Client for NodeMCU
- 20. Conclusions • As you can see, there is a lot more work involved to handle the MQTT protocol compared to Node-RED • Node-RED is very good for rapid prototyping and building demos • Node-RED helps you to focus on the main goal of the app rather than on the implementation details
- 21. Thanks!