Measurement station and tools around the HPCS 6500 spectrophotometer / integrating sphere, for the buildfor.life lamp comparison and for calibrating B4L's tunable-white LED light. Everything is Rust; one binary, lampbench.

Part	Role	Where
HPCS 6500	spectrum, photometry, CRI, electrical, built-in AC/DC supply	driver: submodule `HPCS6500/` (B4L/HPCS6500)
Brother QL-820NWB	lamp ID labels, DK-11221 23x23 mm	`crates/brother-ql`, `crates/lamp-label`
TM-30-18	Rf, Rg and the 16 hue bins from the spectrum	`crates/tm30`
comparison-data	the published lamp bundles	`--data-repo` (git checkout)

Same layout as mppt-testbench: the instrument driver is its own repository, pulled in as a submodule.

Install

git clone --recurse-submodules https://git.b4l.co.th/B4L/lamp-testbench.git
cd lamp-testbench
cargo build --release          # target/release/lampbench(.exe)
cargo install --path .         # or put lampbench on the PATH

The instrument is found by its USB IDs (STM32 virtual COM port, VID 0483, PID 5741); --port COM42 picks one by hand. hpcs6500 (the driver's CLI, cargo install --path HPCS6500) reads and controls the instrument directly.

Lamp station

lampbench station                              # scan -> measure -> commit -> push -> labels
lampbench station --no-push                    # commit locally only
lampbench station --no-commit                  # just write the bundle
lampbench station --settle 0 --readings 1      # quick smoke test
lampbench station --simulate --no-commit --data-repo D:/scratch-data   # no instrument needed

Every lamp gets an internal ID (L0001, L0002, ...) as its primary key; the EAN is optional metadata, so one barcode can cover daylight and warm white variants, and unbranded lamps work too.

Every run opens with a fresh ID; it only becomes real once a bundle is written, so aborting never burns a number.
Scan the box's EAN (Enter skips it) or type an existing ID like L0004 to re-measure that lamp with everything pre-filled (this also rewrites its bundle in the current format). EANs are checksum-validated and resolved to manufacturer / model from previous lamps, the local cache (~/.cache/hpcs6500/ean-cache.json), then upcitemdb.com; GS1-restricted 20-29 barcodes are flagged as retailer-internal. Lamps already measured under the same EAN are offered for re-measurement.
Confirm the identification and type the advertised values from the packaging (flux, CCT, power, CRI, lifetime, equivalent W). They are stored under rated in metrics.json for claimed-vs-measured comparison.
Insert the lamp and press Enter. The procedure: 230 V / 50 Hz from the built-in supply, 60 s settle, 5 readings averaged (vendor single-test cycle per reading).
lamps/<ID>/ is written into the comparison-data checkout, committed and pushed; the website picks it up automatically (data-driven device list, auto-bump deploy). An .md page in the web repo is only needed for photos, buy links or notes.
Two ID labels (QR code of the ID plus the ID, DK-11221) print on the Brother QL-820NWB: one for the box, one for the lamp. Scanning a label at the station types the ID and lands in the re-measure flow. Set HPCS_LABEL_PRINTER=tcp://192.168.1.50 or pass --printer.

Ctrl+C during a measurement switches the supply off and skips the lamp; at the scan prompt, q or Ctrl+C quits.

Defaults assume C:\dev\buildfor_life_web\apps\web\comparison-data with the comparison-data submodule initialized; override with --data-repo.

Lamp bundle export

lampbench export --name philips-a60-8w --manufacturer Philips --model "A60 8W 927"
lampbench export --name philips-a60-8w --readings 5
lampbench export --name philips-a60-8w --voltage 230 --frequency 50 --settle 60   # power from the built-in supply
lampbench export --name some-lamp --parse captures/run.pcap                       # from a USB capture
lampbench export --name x --passive                                               # vendor software drives the instrument

Output lands in lamps/<name>/ (--out):

File
`spd.csv`	`wavelength_nm,value`, the full 380-1050 nm spectrum
`tm30.csv`	TM-30-18 per hue bin: reference/test a' b' (raw and normalized), Rcs, Rhs, Rf,h
`metrics.json`	name, EAN, type, rated values, TM-30 Rf/Rg, CRI Ra + R1-R15, supply, photometric, chromaticity, radiometric, electrical, sensor

The files are byte for byte what the former Python lamp_export.py wrote (tested against its output), so re-measured lamps only change where the measurement changed.

Labels

lampbench label L0006                    # 2 labels on $HPCS_LABEL_PRINTER
lampbench label L0006 --copies 1 --printer tcp://192.168.1.50
lampbench label L0006 --preview l6.png   # render only

TM-30

lampbench tm30 lamps/L0011/spd.csv            # Rf 83.2  Rg 109.3  CCT 4008 K  Duv -0.0370
lampbench tm30 lamps/L0011/spd.csv --bins     # the tm30.csv rows

crates/tm30 implements ANSI/IES TM-30-18 (CIE 2017 colour fidelity, 99 CES, CAM02-UCS, Ohno 2013 CCT) in plain Rust. It reproduces colour-science 0.4.7, which the Python tools used, on 52 golden cases (the published lamps, CIE illuminants, blackbodies, odd grids): Rf and Rg agree to 1e-10, every output to 1e-9 relative or 1e-11 absolute. The spectrum is relative; TM-30 is invariant to its scale.

Known issue: the spectrum's wavelength axis. The CCT/Duv that TM-30 derives from the spectrum (4008 K / -0.037 for L0011) disagree with the instrument's own values (4049 K / +0.0026), because the spectrum's chromaticity on the assumed linear 380-1050 nm axis is 0.09-0.13 (xy) off the instrument's x, y. The published Rf/Rg inherit this. Details and how to confirm the axis: HPCS6500/PROTOCOL.md, "Spectral Data".

LED light calibration

Calibrates the mixing table of the B4L tunable-white light (2700 K + 5000 K LEDs) over its UART, with the HPCS 6500 as the meter:

lampbench calibrate COM3                 # y-data, then up to 10 mixing-ratio passes until all 45 points are within 5 %
lampbench calibrate COM3 --skip-y        # mixing ratios only
lampbench calibrate COM3 --y-only        # LED curves only
lampbench calibrate COM3 --read          # show the table in the light
lampbench calibrate COM3 --clear         # back to firmware defaults
lampbench calibrate COM3 --generate-only # table from calibration_table.json
lampbench calibrate COM3 --write         # ... and write it to the light

Progress and results go to calibration_table.json (--output), in the format of the former calibration.py.

Development

cargo test --workspace        # everything, including the driver submodule
cargo clippy --workspace --all-targets -- -D warnings

tests/golden/bundles/ are bundles written by the Python lamp_export.py from real readings (the driver's tests/fixtures/); bundle.rs must reproduce them byte for byte.
tests/station.rs runs the whole station with scripted answers against the simulated instrument and a throwaway comparison-data repository.
The calibration is tested against a simulated light whose CCT follows its mixing ratio.
crates/tm30/tests, crates/brother-ql/tests, crates/lamp-label/tests compare against the Python libraries (colour-science, brother_ql, qrcode); tools/ in each crate regenerates the golden data.

The Python tools these replace are in HPCS6500 at tag python-final.