The publisher
A simulated sensor generates a value and publishes it to the configured broker. Start with one device and one topic so each message is easy to follow.
IoT & SENSOR NETWORKS
Follow a sensor reading.
Understand its whole journey.
Build a simulated IoT network and explore how telemetry moves from a device through an MQTT broker to a subscriber. Connect messaging behavior with the network that carries it.
MQTT / PUBLISH–SUBSCRIBEEXAMPLE
SensorPublish
BrokerRoute a topic
SubscriberReceive
lab/room/temperature
22.4 °CTHREE ROLES. ONE MESSAGE.
Make publish–subscribe visible.
In a publish–subscribe exercise, the sensor sends a reading to a named topic. The broker matches that topic to subscriptions and forwards the message to connected subscribers. nuLAB lets you investigate this flow alongside the simulated topology.
The broker
The messaging service connects publishers with subscribers. Check broker reachability and the topic before assuming that a missing value is a sensor problem.
The subscriber
A matching subscription receives the published value. Inspect the intended recipient and compare its topic with the publisher’s topic.
A SMALL MQTT EXPERIMENT
A room temperature, delivered.
Use a temperature sensor, a reachable broker, and a subscriber. Give the publisher and subscriber the same topic, then observe a reading such as 22.4 °C moving through the lab.
- Check device addressing and connectivity to the broker.
- Set a topic and a matching subscription using the controls supported by your profiles.
- Observe a publish and its delivery, then change one topic to investigate a mismatch.
Keep the network path unchanged during the topic experiment. That helps you distinguish a messaging mismatch from a connectivity failure.
Message worksheetEXAMPLE
Publisher: Room temperature sensor
Broker: Lab MQTT broker
Topic: lab/room/temperature
Payload: 22.4
Unit: °C
Subscription: lab/room/temperature
Question:
Does the subscriber receive this reading?WHEN A MESSAGE DOES NOT ARRIVE
Investigate the path in layers.
| Layer | Question to ask | What to compare |
|---|---|---|
| Network | Can the publisher and subscriber reach the broker? | Connected links, device addresses, and any routing required by the topology. |
| Messaging | Is the subscriber connected with the intended subscription? | The broker destination, published topic, and subscription filter. |
| Device | Is the sensor publishing the value you expect? | The configured sensor state and observed message, using supported device controls. |
Simulated message delivery helps explain system behavior. It does not establish radio range, battery life, physical sensor accuracy, production broker capacity, or compliance with an industrial safety requirement.
BEFORE YOU START
A few useful answers.
Can I combine IoT devices with a routed network?
You can build scenarios using supported IoT devices and network profiles. Choose the topology, addressing, and messaging features needed for your exercise, and confirm that each is available in your Enterprise configuration.
Which sensors and industrial features are available?
The platform includes profiles for sensor and actuator scenarios, MQTT messaging, and industrial simulation. Coverage varies by device and protocol. Review the platform overview and discuss your required profiles with us.
Does this test real physical sensors or wireless coverage?
This page describes simulated devices and message flows. It does not promise testing of physical sensor accuracy, radio performance, or hardware behavior. See the platform disclaimer.
Is IoT included in the standard individual trial?
IoT and industrial features require an eligible Enterprise plan. Contact us to confirm which access is available for your scenario.
TAKE THE NEXT STEP
Design an IoT exercise you can explain.
Tell us which sensors, messaging behavior, and network conditions you want to explore. We will help establish the fit and required access.
Talk about your IoT scenario