SolderHub Editorial
Articles &
Guides
In-depth tutorials, component deep-dives, and hardware engineering insights — written for builders.
Page 9
Blynk Relay Control with ESP32: Safe Boot and State Synchronization
Build a Blynk-controlled ESP32 relay interface with explicit safe boot behavior, separate requested and reported state, and reconnection synchronization. Covers active-low module differences and why dashboard state is not proof of a switched load.
Blynk vs Node-RED vs Home Assistant vs MQTT: Which Should You Choose?
Compare Blynk, Node-RED, Home Assistant and MQTT by purpose, hosting, dashboards, automation, offline behavior and maintenance. Choose a practical stack for ESP32 and ESP8266 projects without adding unnecessary components.
8-Channel Relay Control with Node-RED and MQTT State Feedback
Build an 8-channel relay dashboard using Node-RED and MQTT with separate command and reported-state topics. Plan reconnect behavior, retained-state policy and safe startup without letting the UI misrepresent the hardware.
HTTP In Node-RED: Build an API and Receive ESP32 POST Data
Create a Node-RED HTTP POST endpoint, send JSON from an ESP32, validate headers and payload fields, return meaningful HTTP status codes, and connect an API response to a flow. Includes network and access-control cautions.
PIR Motion Alerts from Node-RED to Telegram or Email
Turn PIR sensor events into Node-RED Telegram or email alerts without spamming your inbox. Detect state transitions, add a cooldown and test unavailable-network and repeated-trigger scenarios.
Secure Node-RED: Login, HTTPS, MQTT TLS, Backups and Git
Harden a Node-RED deployment with editor authentication, HTTPS or a secure reverse proxy, restricted network access, MQTT security, secret handling and recoverable flow backups. Learn what not to expose to the internet.
Store Node-RED Sensor Data in InfluxDB 2.x and Chart It in Grafana
Build a time-series logging path from Node-RED to InfluxDB 2.x and Grafana. Validate MQTT sensor payloads, write measurements with units, configure a least-privilege token and chart trends without confusing missing samples with zero.
Node-RED Automations: Schedules, LDR Lighting and Context Variables
Build practical Node-RED automations with scheduled Inject nodes, an LDR-based light rule, hysteresis and context variables. Learn to avoid rapid switching, handle stale readings and decide which state should survive a restart.
Reliable Node-RED Flows: Subflows, Link Nodes, Catch and Backups
Organize large Node-RED projects with subflows, Link In/Out nodes, Catch and Status handling, message validation and versioned backups. Learn how to make imports, deployment and recovery more predictable.
ESP32 Relay Control over MQTT with State Feedback
Control relay channels from MQTT with separate command and reported-state topics. Define a safe startup policy, validate commands, handle retained messages carefully and test the relay controller with low-voltage loads.
ESP32 Automatic Plant Watering with Blynk and Soil Moisture Sensor
Build an ESP32 plant-watering system with a soil-moisture sensor and Blynk dashboard. Calibrate wet/dry readings, use hysteresis, limit pump runtime, and keep a safe local policy if Wi-Fi or cloud access disappears.
PIR Motion Notifications with Blynk Events on ESP32
Use an ESP32 PIR input to send Blynk event notifications on a new motion transition. Configure the event, add a cooldown to reduce repeated alerts, and handle sensor warm-up and cloud disconnection.