Battery-powered modular ESP32-S3 field toolkit for authorized NFC, sub-GHz, infrared, USB, and wired hardware debugging experiments, developed first as a serviceable proof of concept and later as a sealed handheld.

STM32L4 Discovery kit IoT node, low-power wireless, BLE, NFC, SubGHz, Wi-Fi

Single M5Stack Cardputer ADV HAT integrating CC1101 sub-GHz radio, nRF24L01+ PA/LNA 2.4GHz radio, LoRa RA-02, and PN532 NFC with shared host interface, 3.3V power distribution, decoupling, and RF layout constraints.