Lesson 3 – To show or not to show?

🧑‍💻 Duration: 30 minutes
🎯 Target audience: individuals (or groups that get along)

1. Introduction

You can already connect HARDWARIO TOWER modules and show their outputs in charts and on gauges.

In this lesson, we will go deeper into programming in HARDWARIO Playground. You will learn to:

• work with messages (messages)
• filter them by topic
• create conditional outputs (for example, turn on an LED only when a value meets a certain condition)

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

2. What’s ready

✅ The PIR Module is connected, powered and paired.
✅ Playground receives data on orientation, temperature and the presence of a person.
✅ The dashboard shows the current values from the module.
✅ You know how to show or adjust the values again if they disappear.

3. Who starts it all

Start your flow with an mqtt in node that subscribes to the orientation messages. In my case, the topic is node/motion-detector:0/orientation, but yours may differ slightly depending on the device name.

info

To work with a message, it first has to arrive. The PIR sensor is great for testing, or more precisely the accelerometer in its Core Module, because you can easily change how many messages arrive and how often simply by tilting the module.

You already know from the previous lesson what the node returns: you can, for example, plot its output in a chart. For a better understanding, though, we recommend connecting the output of the mqtt in node to a debug node.

• By default, the debug output shows the content of msg.payload, the actual value coming from the sensor.
• On my PIR Module, numbers from 1 to 6 appear, depending on how it is turned. This is exactly the value we will work with.

4. Switch splits the output

The Switch node (in the Function section) has one input and at least one output. Once you open it, you can give it a name to keep your flow easy to follow.

• In the Property field, set the value the node should work with, in this case msg.payload.
• Below, define the conditions for each output.

For this task, we are interested in the case when the orientation is 6 (the module is lying on the PIR sensor). The otherwise option at the end of the list of conditions catches everything else.

5. Change modifies the message

At this point, msg.payload still holds 1–5 or 6, depending on which Switch output the message went through.

• The Change node changes msg.payload to the text you choose.
• In my case:
  • values payload 1–5 → “I am calm”
  • value payload 6 → “Careful, I’m falling”

So you use two Change nodes.

6. Text on the dashboard

You show text with the Text node from the Dashboard section.

• Give it a name (for example “What about the PIR sensor?”)
• Set it to display msg.payload, which now holds “I am calm” or “Careful, I’m falling”.

7. From number to text

Does it work?
When you turn the PIR Module, you should see the text on the dashboard change:

• “I am calm” → at orientation 1–5
• “Careful, I’m falling” → at orientation 6

If you also have the Gauge node from the previous lesson, you will see the current orientation of the PIR Module at the same time.

8. Guard

So far, you have used the PIR Module as a die that knows which side it is lying on.

Now use it as a real motion detector!

👉 Program it to watch for the presence of a person and to write on the dashboard whether it sees someone or not.

9. Summary

✅ The input generates messages, and you can change them with Change.
✅ You can filter messages with Switch and pass them on to other nodes.
✅ You show your own messages on the dashboard.