ESP32 and Arduino tutorials: sensors, MQTT, TLS, deep sleep and OTA, with examples connected to the public broker broker.connectmq.com.
Connect an ESP8266 NodeMCU to an MQTT broker with PubSubClient, publish JSON telemetry, control the onboard LED, then add TLS with BearSSL while keeping the limited heap under control.
Turn an ESP32 and a cheap SSD1306 OLED into a live MQTT display that shows sensor values and messages from any device, flags stale readings and shows its own connection status.
A systematic troubleshooting guide for when your ESP32 cannot connect to an MQTT broker, covering Wi-Fi, DNS, ports, TLS certificates, credentials, client IDs and PubSubClient state codes.
Publish accelerometer and gyroscope readings from the Arduino Nano 33 IoT to an MQTT broker using WiFiNINA, WiFiSSLClient and ArduinoMqttClient, then harden it with credentials and a Last Will.
Why ESP32 MQTT sketches trigger task watchdog resets, how to read the task_wdt message, and how to restructure reconnect loops, callbacks and blocking code so the watchdog stays quiet.
A complete guide to the official ArduinoMqttClient library: the connection API, why poll() matters, streaming publish and receive, QoS and retain flags, will messages and every connectError() code.
Measure tank level with a waterproof ultrasonic sensor, convert distance to litres and percent full on an ESP32, and publish retained MQTT readings plus debounced low-level alerts.
Detect motion with an HC-SR501 or AM312 PIR on an ESP32, debounce noisy triggers, publish motion events over MQTT and keep a retained last-motion timestamp for dashboards and automations.
Build a battery-friendly ESP32 sensor that wakes on a timer, connects quickly, publishes a retained reading, confirms it reached the broker and goes back to deep sleep.
Configure a retained Last Will and Testament plus a birth message on the ESP32 so every dashboard and script can see device availability instantly, including after crashes, power cuts and Wi-Fi loss.
Drive a WS2812B addressable LED strip from an ESP32 with JSON MQTT commands for color, brightness and effects, and publish retained state so every dashboard stays in sync.
Turn an AI-Thinker ESP32-CAM into an MQTT camera that publishes JPEG snapshots on demand or on a timer, stays inside broker message limits and saves every frame with a small Python subscriber.
Get an ESP32-C6 publishing to broker.connectmq.com with Arduino core 3.x, control its RGB LED from the command line and understand the differences from the classic dual-core ESP32.
Connect an ESP32 to an MQTT broker over 4G LTE with a SIM7600 modem, TinyGSM and PubSubClient, recover from network drops and keep cellular data usage and costs under control.
Wire a DHT22 to an ESP32, read temperature and humidity reliably, publish JSON to broker.connectmq.com and view the live readings in the ConnectMQ topic explorer.
Create an account, get your broker credentials and connect your first device — no servers to install, patch or scale.
