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Lesson 3 - To show or not to show?

πŸ§‘β€πŸ’» Duration: 30 minutes
🎯 Target audience: individuals (or groups that don’t argue)

1. Introduction​

You already know how to connect HARDWARIO TOWER modules and display their outputs using charts and gauges.

In this lesson, we will dive deeper into programming in the HARDWARIO Playground environment. You will learn how to:

  • work with messages (messages)
  • filter them by topic
  • create conditional outputs (e.g., turn on an LED only when a certain value is met)

This way, you will start programming the system behavior, not just collecting data.

2. What’s Ready​

βœ… The PIR Module is connected, powered, and paired.
βœ… Playground is receiving data about orientation, temperature, and presence.
βœ… The dashboard displays current values from the module.
βœ… You know how to display or adjust the values again if they disappear.

3. Who Starts It All​

In your flow, start with the mqtt in node, which will subscribe to orientation messages.
In my case it is named: node/motion-detector:0/orientation, but on your device it may differ slightly depending on the module name.

info

In order to work with a message, it must arrive first. For testing, the PIR sensor is perfect, specifically its gyroscope, because you can easily influence the number and frequency of messages simply by tilting the module.

You already know from the previous lesson what this node returns β€” for example, it can be plotted on a chart.
For better understanding, however, we recommend connecting the output of the mqtt in node to a debug node.

  • By default, the debug output displays the content of msg.payload, i.e., the actual value coming from the sensor.
  • On my PIR Module, numbers in the range 1 to 6 appear depending on its orientation β€” and this is exactly the value we will work with further.

4. Switch Splits the Output​

The Switch node (from the Function section) has one input and at least one output.
After opening it, you can name the node, which will help you keep your flow organized.

  • In the Property field, set the value the node should work with β€” in this case msg.payload.
  • Below, define the individual output conditions.

For this task, we are interested in the situation when the orientation has the value 6 (the module is lying on the PIR sensor).
Everything else will be caught using the otherwise option, which is located at the end of the condition list.

5. Change Modifies the Message​

At this point, msg.payload is still set to a value of 1–5 or 6, depending on which Switch output the flow is currently using.

  • The Change node modifies msg.payload to your chosen text value.
  • In my case:
    • values payload 1–5 β†’ "I am calm"
    • value payload 6 β†’ "Careful, I’m falling"

So two Change nodes are used.

6. Text in the Dashboard​

To display text, use the Text node from the Dashboard section.

  • Give it a name (e.g., β€œWhat about the PIR sensor?”)
  • Set it to display msg.payload β€” at this point, it will take

7. Guard​

So far, the PIR module has been used as a gyroscopic cube. Now, use it as a proper PIR sensor!

πŸ‘‰ Program it so that it monitors the presence of a person and writes to the Dashboard whether it detects someone or not.

8. Summary​

βœ… The input generates messages, and you can modify them using Change. βœ… You can filter messages using Switch and pass them on to other nodes for processing. βœ… In the Dashboard, you print your own messages.