Various Projects Find Hidden SDR Capabilities in ESP32 Microcontrollers

ESP32 microcontrollers contain an undocumented feature that bypasses WiFi/Bluetooth and captures raw IQ baseband samples, enabling internal SDR operation from 2.2–2.7 GHz (and 4.8–6.0 GHz on ESP32-C5) at up to 80 MS/s and 13–54 MHz analog bandwidth. The ESP32-S31 can stream continuously at 16 MS/s via Gigabit Ethernet, with SoapySDR drivers forthcoming, while other projects use FPGA front-ends or FPV receivers to extend functionality.