This is a simple project to show the capabilities of Node-RED. Goal of the project is to switch on or off a led remotely, from a smartphone or a laptop. To accomplish this, two devices will be used: a NodeMCU and a Raspberry. 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
• A log file that will be updated each time that the led is turned on or off

To interact with the led, it is required to open a web browser and connect to «yourIP:1880/ui/».

Note: if you want to switch on or off the led from an external network, you need to:

• Change the firewall to allow inbound traffic on port 1880
• Set up a Network (and/or Port) Address Translation (NAT/PAT) entry that links requests from any address on port 1880, to 192.168.1.2 on port 1880.

Of course, security issues must be taken into account before doing this procedure.

Link to presentation slides: https://www.slideshare.net/DavidGhedalia/nodered-96151736