Various Projects Find Hidden SDR Capabilities in ESP32 Microcontrollers
4 hours ago
- ESPARGOS discovered an undocumented feature in several ESP32 chips allowing raw IQ baseband capture, bypassing fixed WiFi/Bluetooth functionality.
- Several ESP32 models can now function as internal SDRs covering 2.2–2.7 GHz and 4.8–6.0 GHz (on ESP32-C5), with up to 80 MS/s sample rate and 13–54 MHz analog bandwidth.
- For general-purpose PC-connected SDR, output bandwidth is limited, so only snapshots can be exported, restricting use to spectrum analysis; however, the ESP32-S31 can stream continuously at up to 16 MS/s over Gigabit Ethernet.
- ESPARGOS now supports phase-coherent IQ capture, enabling direction finding on any arbitrary signal in the 2.4 GHz band, not just WiFi and Bluetooth.
- Independently, two other projects found similar features: h0m3us3r's project streams raw IQ continuously via an FPGA (with phase noise issues), and C5VRX uses an ESP32-C5 as a 5.8 GHz real-time FPV video receiver via an undocumented IQ data stream.