ESP32-S3 probe – a UART "flight recorder" with auto frame decoder

Name: ESP32-S3 probe – a UART "flight recorder" with auto frame decoder
Availability: InStock
Author: octablock

by octablock·Feb 20, 2026·2 points·0 comments

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AI Analysis

●●●BangerWizardrySolve My ProblemDark Horse

DIY logic analyzer: COBS framing + auto-CRC brute-force replaces $500 tools on a $20 chip.

Strengths

•Solves real friction: detects packet drops, jitter, and frame corruption that terminal UARTs hide
•Clever framing and replay: COBS encoding + offline .anlog files enable robust recovery and reproducible debugging
•Smart auto-decoder: magic-byte scanning + CRC brute-force learns unknown frame formats without code changes

Weaknesses

•Windows-only standalone EXE limits adoption; Linux/Mac users must run from Python source
•Only 921600 baud max; some modern MCUs (STM32H7) go 3+ Mbps, so limited ceiling

Post Description

Hi HN,

I built a small UART analyzer using an ESP32-S3 as a cheap probe. It taps the target’s TX at 921600 baud and streams raw bytes to the PC over USB CDC.

On the PC side (Python/Tkinter), the UI shows: - RAW hexdump + throughput graph + health stats (seq gap / overflow) - LOG/TEXT views (extract printable ASCII runs) - Record/Replay (.anlog) for offline reproduction - AUTO parser: scans magic bytes and brute-forces CRC variants for unknown inner frames

This started as a personal debugging bridge between firmware and host, and helped me catch dropped chunks, burst patterns, and protocol mistakes without a logic analyzer.

Repo: https://github.com/choihimchan/linkscope-bpu-uart-analyzer

I’d love feedback on framing, replay formats, or parsing heuristics. Thanks!