Connected Devices: MQTT, Bluetooth Low Energy and ESP-NOW

10 Lektionen in dieser Stufe

1. Publish and Subscribe: How MQTT Decouples Devices
   Explain broker, client, topic and message and why devices need not know each other. · Lab: Sketch the message flow of a three-device system on paper.
2. Running a Local Mosquitto Broker and Command-Line Clients
   Install a broker on a computer and exchange test messages by hand. · Lab: Publish and subscribe from two terminals, including wildcard subscriptions.
3. Publishing Sensor Data from an ESP32
   Connect to the broker and send readings as JSON at a sensible interval. · Lab: Publish temperature and humidity every 30 seconds and watch them arrive in a terminal.
4. Subscribing to Commands and Designing Topic Trees
   Receive messages in a callback and structure topics for many devices. · Lab: Control a relay by topic and define a naming scheme for site, room, device and channel.
5. Quality of Service, Retained Messages and Last Will
   Choose delivery guarantees and make device status visible when it drops offline. · Lab: Add an availability topic with last will and show the offline state after pulling power.
6. Robust Reconnect Logic with Backoff
   Recover from Wi-Fi and broker outages without blocking or flooding the network. · Lab: Stop the broker for a minute and confirm buffered readings arrive after reconnecting.
7. Dashboards and Automation Flows with Node-RED
   Visualise and react to MQTT data without writing a full application. · Lab: Build a dashboard with gauges, a chart and a rule that switches the relay on a threshold.
8. BLE Fundamentals: GATT Services and Characteristics
   Describe advertising, connections and the attribute model. · Lab: Explore a commercial BLE device or another ESP32 with a phone scanner app and list its services.
9. A BLE Peripheral with Notifications to a Phone
   Create a custom service that notifies readings and accepts written settings. · Lab: Send live sensor values to a phone app and change the reporting interval from the phone.
10. Router-Free Links with ESP-NOW
    Exchange small packets directly between ESP32 boards with fast wake-up and low energy. · Lab: Send readings from a deep-sleeping node to a gateway and measure the awake time per report.

Abschlussprojekt

A multi-room sensor network in which battery ESP-NOW nodes report to a gateway that publishes to MQTT, feeds a dashboard and offers BLE configuration from a phone.

Teile für diese Stufe

• 3 × ESP32 development board
• 3 × USB cable matching the board
• 3 × Solderless breadboard 830 points
• 1 × Jumper wire set male-male and male-female
• 2 × BME280 pressure, humidity and temperature module
• 1 × DHT22 temperature and humidity module
• 1 × PIR motion sensor module
• 1 × Relay module 3.3 V compatible single channel
• 4 × LED 5 mm assorted
• 4 × Resistor 220 ohm
• 2 × Tactile push button
• 2 × Li-ion cell 18650 protected
• 2 × 18650 battery holder
• 2 × Low-quiescent 3.3 V regulator module

In jeder Lektion legst du die passenden Teile direkt in den Warenkorb. Arduino-kompatibel →