Thank you to "Geo" for writing in and sharing with us his open source project called "ESP32-Bus-Pirate" which he thinks might be of interest to those in the RTL-SDR community. The ESP32 is a popular low-cost microcontroller due to the fact that it has WiFi and Bluetooth capabilities built in. Although the ESP32 does not have true SDR capabilities, it can leverage its numerous built-in hardware radio components to achieve various interesting feats. Geo writes:

This firmware turns an inexpensive ESP32-S3 board into a multi-protocol debugging and hacking tool, inspired by the original Bus Pirate and the Flipper Zero.

It currently supports a wide range of protocols and devices, including I²C, SPI, UART, 1-Wire, CAN, infrared, smartcards, and more. It also communicates with radio protocols as Subghz, RFID, RF24, WiFi, Bluetooth.

Compared to existing solutions, the focus is on:

Accessibility — runs on cheap ESP32-S3 hardware (around $7–$10).

Versatility — one device can probe, sniff, and interact with multiple buses.

Extensibility — open-source and modular, making it easy to add new protocol support.

I believe this could be useful for hardware hackers, security researchers, and hobbyists looking for a low-cost, flexible alternative to commercial tools.

With the firmware installed on a compatible ESP32 device, it is possible to create WiFi, Bluetooth, and RF24 sniffers, scanners, and spoofers, as well as perform general sub-GHz and RFID sniffing, scanning, and replay attacks. It also has a host of non-RF capabilities useful for hacking devices.