Screen Brightness — tdlidar_brightness

Steal the phone’s own brightness slider and use it as a spare 0–1 fader for anything in your scene.

Category: Device · Tier: Free · Needs: any iPhone (no special hardware)

What it does

Streams the phone’s screen brightness as a single 0–1 value. On its face it tells you how bright the display is, but its real use is as a free hardware fader: the brightness slider in iOS Control Center is smooth, always available, and tactile, so you can repurpose it to drive any parameter in TouchDesigner without building a custom control surface.

OSC in

address type range rate
/tdlidar/device/brightness float 0–1 2 Hz

Outputs

  • out1 (CHOP) — one channel: tdlidar/device/brightness (0–1).

Parameters

par default what it does
OSC Port 9000 UDP port to listen on (match the app)

Quick start (beginner)

  1. Enable device sensors in the app.
  2. Drop tdlidar_brightness.
  3. Drag the brightness slider on the phone (Control Center) and watch out1 glide 0→1.
  4. Export out1 onto any TOP/SOP parameter to use it as a live fader.

Advanced patterns

  • Spare fader (the point of this op): Math/Range CHOP remap 0–1 to whatever range your parameter needs — e.g. 0–1 → 0.5–4.0 for a feedback gain, or 0–1 → 0–360 for a hue rotate.
  • Smooth the steps: updates arrive at 2 Hz, so the raw signal stairsteps. Put a Lag/Filter CHOP after it (lag ~0.3 s) before driving anything visible, or it will feel notchy.
  • Detents: if you want discrete stops instead of a continuous fade, run it through a Math CHOP (floor(value*N)/N) to quantize to N steps you can feel on the slider.
  • Pair with another sensor: use brightness as the amount and a gesture/beat as the trigger — brightness sets how strong an effect lands when an onset fires.

Gotchas

  • 2 Hz only — it is not a per-frame control. Always Lag/Filter it before it touches anything the audience sees.
  • iOS auto-brightness will move this value on its own as room light changes; turn auto-brightness off on the phone if you want it to behave purely as a manual fader.
  • Raising brightness drains the battery faster — watch tdlidar_battery if you park the slider near 1 for a long install.