SolderHub Editorial
Articles &
Guides
In-depth tutorials, component deep-dives, and hardware engineering insights — written for builders.
Page 6
Test MQTT without Hardware: Mosquitto Clients and MQTT Explorer
Verify a broker and topic flow before connecting any microcontroller. Use mosquitto_pub and mosquitto_sub in two terminals, inspect topics with MQTT Explorer, and diagnose local versus remote broker access.
How to Build an Amateur Radio Telegraph Practice Oscillator (And Learn Morse Code the Way Hams Actually Do)
Build a working Morse code practice oscillator two ways -- a classic 555 timer circuit and an Arduino version -- then learn the code the way real CW operators do, with no license required to start.
STM32 vs Arduino: Which Should You Choose in 2026?
A direct, practical comparison of STM32 and Arduino — specifications, real-world performance limits, code differences, and exactly when it's time to move from an Uno to a Blue Pill.
MQTT Topic Naming Best Practices for IoT Projects
Design MQTT topic hierarchies that stay readable as IoT projects grow. Learn device naming, telemetry versus commands, wildcard filters, case sensitivity, retained state and topic permission patterns.
ESP32 Complete Beginner's Guide: WiFi, Bluetooth, Web Server (2026)
The ultimate 2026 guide to the ESP32. Learn the pinout, how to connect to WiFi, build web servers, use Bluetooth BLE, and run on battery with deep sleep.
Retained Messages and Last Will with ESP32: Online/Offline Status
Use MQTT retained status and Last Will and Testament (LWT) to show whether an ESP32 is online. Configure status topics safely, test unexpected disconnects, and separate availability from sensor freshness and retained commands.
ESP32-H2 Pinout Guide: GPIO, ADC, and the WiFi-Free Thread/Zigbee Radio Explained
A complete ESP32-H2 pinout reference — verified strapping pins, GPIO, ADC, PWM, and why this is the one ESP32 chip built with no WiFi at all, focused entirely on Bluetooth LE and Zigbee/Thread/Matter.
XIAO ESP32C6 Pinout Guide: Every GPIO on Seeed's Matter-Ready Tiny Board
A complete Seeed XIAO ESP32C6 pinout reference — all 11 GPIOs, ADC, boot-sensitive pins, and the WiFi 6 / BLE 5.3 / Thread-Zigbee radio set packed into a thumbnail-sized board.
Arduino Nano ESP32 Pinout: GPIO, Dual Numbering Modes, and VBUS Explained
A complete Arduino Nano ESP32 pinout reference — the classic Nano header layout wrapping a real ESP32-S3, its dual pin-numbering modes, three hardware UARTs, and the missing 5V pin.
Raspberry Pi 5 Pinout: GPIO, RP1, and What Actually Changed from the Pi 4
A complete Raspberry Pi 5 GPIO reference — the unchanged 40-pin header, plus the RP1 companion chip, the gpiochip4 change, and exactly which GPIO libraries still work.
Raspberry Pi Pico 2 Pinout: Every GPIO, ADC, and RP2350 Feature Explained
A complete Raspberry Pi Pico 2 pinout reference — GPIO, ADC, PWM, I2C/SPI/UART, and what the RP2350 chip actually changes versus the original RP2040-based Pico.
XIAO ESP32C3 Pinout Guide: Every GPIO on Seeed's Thumbnail-Sized Board
A complete Seeed XIAO ESP32C3 pinout reference — all 11 GPIOs, ADC, I2C/SPI/UART defaults, boot-sensitive pins, and the onboard LiPo charging circuit that makes this board built for battery projects.