ESP32RET — CAN Bus Reverse Engineering Tool with SavvyCAN
Turns the LILYGO T-CAN485 into a sub-$15 professional CAN bus reverse engineering and sniffing tool with WiFi streaming to the SavvyCAN desktop analyzer, ELM327 emulation, and SD card logging.
Overview
ESP32RET (347+ GitHub stars) is the companion firmware for SavvyCAN (1,500+ stars), a professional-grade cross-platform CAN bus analysis tool. Together they turn the LILYGO T-CAN485 into a fully capable CAN bus sniffer and reverse engineering station — replacing commercial tools that cost hundreds of dollars with a sub-$15 solution.
Key Features
- CAN Bus Sniffing: Capture all CAN frames in real time via the T-CAN485's built-in CAN transceiver
- WiFi Streaming: Stream CAN data wirelessly to SavvyCAN desktop application (Qt-based, cross-platform)
- ELM327 Emulation: Acts as an ELM327 OBD-II adapter for compatibility with standard car diagnostic apps
- SD Card Logging: Record CAN bus traffic to SD card for offline analysis
- Frame Filtering: Configure hardware filters to capture only specific CAN IDs
- Dual Interface: Use both CAN bus and RS-485 interfaces on the T-CAN485 simultaneously
- SavvyCAN Integration: Full integration with SavvyCAN's signal decoding, DBC file support, graphing, and scripting
Getting Started
Flash ESP32RET firmware via PlatformIO onto the T-CAN485. Connect CAN-H and CAN-L to your vehicle's OBD-II port or industrial CAN bus. Open SavvyCAN on your computer, connect via WiFi to the ESP32's IP address, and begin capturing frames. SavvyCAN can decode signals using DBC database files for popular vehicles.
Why This Project
Automotive and industrial CAN bus analysis typically requires expensive hardware (Peak, Kvaser, Vector adapters). The T-CAN485 with ESP32RET delivers comparable capture capabilities over WiFi for under $15. Community members have used this setup for vehicle reverse engineering, custom gauge clusters, battery management system monitoring, and industrial equipment debugging.
