Film the flash-family effects on the roofline controller to verify the photosensitivity table #168

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opened 2026-09-26 09:12:50 +00:00 by claude-bot · 0 comments

claude-bot commented

2026-09-26 09:12:50 +00:00

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Why

The photosensitivity guard (#150 / #167) enforces limits taken from backend/app/data/flash_safety.json. That table was derived from WLED 16.0.0's firmware source (wled00/FX.cpp at commit 4374f01), not measured, and it carries verified_on_hardware: false. The derivation assumes the worst-case frame time and uses conservative judgement. It still needs one real measurement, the same way #21 measured transition wrap on the device instead of trusting the documentation.

Method (also in `docs/photosensitivity.md`)

Film each row at 240 fps on a phone, pointed at the roofline controller, and count flashes per second.
Speed-limited effects:
- Blink, Strobe, Strobe Rainbow and Blink Rainbow at sx 238 (the limit) and 239. Expect about 2.9/s and about 3.1/s.
- Dynamic at sx 247 and 248.
Unsafe effects (Strobe Mega, Lightning, Chase Flash, Chase Flash Rnd, Sparkle+): confirm they really do exceed 3/s at their default and minimum speeds. The table claims they have no safe speed.
Judgement calls:
- Fire Flicker first. The table allows it because the flicker averages out across pixels. Confirm it doesn't read as a whole-segment flash on a real run of LEDs.
- Single-pixel sparkles (Sparkle, Sparkle Dark, Glitter): confirm they don't read as a general flash at the roofline's pixel density.
Check the effective frame rate on this controller (/json/info → fps). Limits were computed at the 2 ms worst case. If the real frame rate is much lower, record that too, but don't loosen the table on the strength of one controller's frame rate.

Done when

Measurements are recorded in docs/photosensitivity.md (effect, sx, measured flashes per second, date, firmware).
Any row that disagrees is corrected, with its test updated.
verified_on_hardware is set to true, per row or for the whole table.

## Why The photosensitivity guard (#150 / #167) enforces limits taken from `backend/app/data/flash_safety.json`. That table was **derived from WLED 16.0.0's firmware source** (`wled00/FX.cpp` at commit `4374f01`), not measured, and it carries `verified_on_hardware: false`. The derivation assumes the worst-case frame time and uses conservative judgement. It still needs one real measurement, the same way #21 measured `transition` wrap on the device instead of trusting the documentation. ## Method (also in `docs/photosensitivity.md`) - Film each row at 240 fps on a phone, pointed at the roofline controller, and count flashes per second. - **Speed-limited effects:** - Blink, Strobe, Strobe Rainbow and Blink Rainbow at `sx` 238 (the limit) and 239. Expect about 2.9/s and about 3.1/s. - Dynamic at `sx` 247 and 248. - **Unsafe effects** (Strobe Mega, Lightning, Chase Flash, Chase Flash Rnd, Sparkle+): confirm they really do exceed 3/s at their default and minimum speeds. The table claims they have no safe speed. - **Judgement calls:** - **Fire Flicker first.** The table allows it because the flicker averages out across pixels. Confirm it doesn't read as a whole-segment flash on a real run of LEDs. - Single-pixel sparkles (Sparkle, Sparkle Dark, Glitter): confirm they don't read as a general flash at the roofline's pixel density. - **Check the effective frame rate** on this controller (`/json/info` → `fps`). Limits were computed at the 2 ms worst case. If the real frame rate is much lower, record that too, but don't loosen the table on the strength of one controller's frame rate. ## Done when - Measurements are recorded in `docs/photosensitivity.md` (effect, `sx`, measured flashes per second, date, firmware). - Any row that disagrees is corrected, with its test updated. - `verified_on_hardware` is set to `true`, per row or for the whole table.

claude-bot added this to the v1.2.0 milestone

2026-09-26 09:13:01 +00:00

claude-bot added the

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2026-09-26 09:13:02 +00:00

claude-bot referenced this issue from a commit

2026-09-26 09:27:00 +00:00

Keep strobes under 3 flashes a second (#150) (#167)