dsh-ls125-uv-probe
A DeepSeek Harness skill plugin for the 林上 LinShang LS125 紫外辐照计 and its
UVALED-X3 UV probe: the private UART protocol between the meter and the probe,
reverse-engineered end to end, plus the tooling to capture and decode it and a
verified host firmware that replaces the original meter.
中文说明：README.zh.md
Install it and your agent gains a ls125-uv-probe skill — the protocol table, the
commands, the toolchain usage, and the traps that make a working setup look dead.
What it answers
| Question | Answer |
|---|
| Can I read this probe from my own MCU, without the original meter? | Yes — verified on an STM32F103: 21/21 frames, zero CRC errors, zero timeouts |
| What is the protocol? | 9600 8N1, polled every 500 ms, 28-byte replies, CRC-16/MODBUS |
| Is there a hidden handshake, challenge, or ID check? | No — the poll command is a constant 8-byte string |
| Can I reset the probe's records? | Yes — a second command; it clears energy, minimum, and the elapsed-time counter |
| Do I have to send the meter's startup configuration? | No — polling alone is enough (verified) |
Install
dsh plugin --profile web add dsh-ls125-uv-probe
Or straight from this repository:
dsh plugin --profile web add github:2333hutao/dsh-ls125-uv-probe
Protocol at a glance
主机 → 探头 轮询（每 500 ms） AB 20 60 00 14 00 89 07
清零 AB 21 20 00 02 00 01 00 3D 8A
探头 → 主机 28 字节帧，帧头 AB 20 60 00 14 00
偏移 6–9 float LE 实时辐照度 µW/cm²（表显 mW/cm² = ÷1000）
偏移 10–13 float LE 累积能量 µJ/cm²
偏移 14–15 uint16 LE 距上次清零的时间 ×0.1 s
偏移 16–17 2 字节 恒 0（含义未定）
偏移 18–21 float LE 最小值 µW/cm²
偏移 22–25 float LE 平均辐照度 µW/cm²
偏移 26–27 uint16 LE CRC-16/MODBUS（over 0–25，poly 0xA001 / init 0xFFFF / LSB-first）
Frame values are always µW/cm² and µJ/cm² regardless of the meter's display
unit setting, so a host never has to track that setting. The maximum is not in
the frame — the meter computes it, and so should you.
What ships in here
skill/SKILL.md the skill body (protocol quick table, commands, toolchain usage, hard rules)
skill/PROTOCOL.md full specification, command families, reference C implementation
skill/LESSONS.md transferable methodology + 13 measured pitfalls with their verdicts
skill/AGENTS.md a takeover briefing for an agent landing in the workspace
skill/tools/ fx2cap.cjs (capture, official libusb + fx2lafw) and four decode/analysis scripts
skill/firmware/ f103_probe (verified host) and f103_rgb (controllable light source)
skill/captures/ a sample capture so the toolchain can be exercised with no hardware
The toolchain bypasses a long-standing sigrok problem: every Windows sigrok build
statically links a 2016 libusb whose backend dispatch fails on some systems, so
fx2lafw reports LIBUSB_ERROR_NOT_SUPPORTED while --scan still lists the
device. Reinstalling drivers does not help. fx2cap.cjs talks to the device with
an official libusb instead, and adds what sigrok lacks: no capture duration cap
and a soft trigger.
Evidence, not assertions
Every claim above was measured, and the repository keeps the measurements: three
rounds of "frame value ↔ meter display" matched to all four decimals, a 65536-polynomial
brute force that found the checksum, a halt test that proved the probe never speaks
unless polled, and four independent experiments that ruled D4 out as a reset line.
How this was built — AI authorship disclosure
All of the code, firmware, tooling and documentation in this repository was written by an
AI agent (DeepSeek Harness), working from measurements taken on real hardware.
The protocol knowledge here was not copied from a datasheet, a vendor document, or a
third-party implementation — it was captured off the wire, cross-checked against the meter's
own display, and every claim is backed by a recorded experiment. Nothing in skill/ is
asserted without a measurement behind it, and the few open items are labelled as open.
A human operator did the parts an AI cannot: wiring, power, probes, pressing the meter's
own keys, and reporting what its display showed.
Review it as you would any machine-written code before relying on it. The measurement
evidence is all here, so the claims can be re-checked rather than taken on trust.
License
MIT
