Guides

Pinouts. Tutorials. Answers.

Chip and board pinouts, plus sensor and module reference guides: real GPIO tables, real specifications, and working code for each one.

Reference CC1101 868MHz SPI RF Module – Complete Guide A programmable sub-GHz transceiver for the 868 MHz ISM band with hardware packet handling, CRC and RSSI built in. This guide covers the pinout, ESP32 wiring, ESP-IDF SPI setup, register configuration, and how it compares to LoRa. Read guide

Reference PN532 NFC Module Complete Guide The PN532 reads and writes NFC tags, including the kind your phone already uses for tap-to-pay and tap-to-share, not just the 13.56MHz RFID cards the already-published RC522 handles. This guide covers its three interfaces, wiring it to an ESP32 over I2C, and when you actually need NFC over plain RFID. Read guide

Reference ESP8685-WROOM-03 Pinout The complete pin reference for the ESP8685-WROOM-03: 11 castellated pads, 8 GPIOs, six test points, Wi-Fi and Bluetooth LE in 15.0 x 17.3 mm. Read guide

Guide ESP32-C2 (ESPC2-02) Pinout The complete pin reference for the ESPC2-02 module: Espressif’s smallest, lowest-cost Wi-Fi and Bluetooth chip, and the exact pins you can safely reuse. Read guide

Reference Seeed Studio XIAO ESP32S3 Pinout The real pin reference for Seeed Studio's XIAO ESP32S3: thumbnail-sized, native USB, with a camera/display connector on the Sense variant. Read guide

Reference SCD40 / SCD41 CO2 Sensor Complete Guide The SCD40 and SCD41 measure actual CO2 concentration using photoacoustic NDIR sensing, something a temperature/humidity sensor like the BME280 or SHT series cannot do at all. This guide covers both chips' real specs, wiring one to an ESP32, and the common beginner mix-up between CO2 sensing and air-quality/humidity sensing. Read guide

Reference The Ultimate Guide to the BL0942 Energy Meter IC A calibration-free, register-driven single-phase energy metering IC: active power, RMS, line frequency and zero-crossing, all exposed over UART or SPI instead of pulse-counting alone. This guide covers its pinout, digital interfaces, and how it compares to the older BL0937. Read guide