Expected completion time of this lab:
- The IBM Watson IoT platform acts as an MQTT broker: applications publish messages to it, others subscribe to messages.
- in Node-RED, you subscribe to messages through the ibmiot input node:
by double-clicking on that node, you can configure the following (leave other fields untouched):
Authentication set to "API Key" API Key
Functions like a username/password pair to authenticate to the Watson IoT Platform
Tip icon false
You instructor has already created a key. Ask for it.
Input Type set to "Device Event" Device Type allows you to choose the type of device you want to subscribe to, in this lab either "manager" or "mote" Device Id unique identifier of the device, in this lab its MAC address, e.g. "00-17-0d-00-00-58-f5-23" start by creating the following flow in which you subscibe to all devices types, all device ids, all event types and all formats. Event The type of event you want to subscribe to, e.g. "oap.temperature"
on your IBM Cloud-based Node-RED, instance, start a flow which subscribes to all events.
- make sure you see the messages appear in the debug tab
modify the flow by inserting a function node with the following code:
var count = flow.get('count')||0; count += 1 flow.set('count',count); msg.payload = count; return msg;
What does the function above do?
Info icon false title Answer 1:
How many messages are published per minute to the Watson IoT platformbroker, on that topic?
Info icon false title Answer 2:
Each MQTT message contains a topic, a string identifying the type of message. The following topics are examples of what is used by Watson IoT: