This page needs JavaScript to read the lid sensor. Read the setup instructions on GitHub.
Instrument
Appearance
Ready to start.
Connect a sensor and receive a fresh angle to begin.
Your angle—
For the best experience, open your browser in full screen.
Read your MacBook’s lid angle as you move the screen. For a little challenge, find three random angles from the menu.
Use desktop Chrome or Edge, or keep Safari and run the local native reader.
Use desktop Chrome or Edge with a compatible MacBook. Choose the lid sensor when asked. No download needed.
Run the local helper on your Mac. Requires Python 3 and Apple’s Swift compiler. Works with Safari, too.
More frequent readings in native mode on the tested Mac: about 50 reads/sec versus one browser report/sec. Rates vary; this compares read frequency, not measured latency.
Requires a compatible MacBook with a readable lid-angle sensor. Check your model in the compatibility guide below.
Move within the screen’s normal range. The challenge is a local experiment, not secure proof that a human is present.
You can reopen this guide from Menu → About & setup.
Both modes read the same built-in lid sensor. Choose browser access for a quick start, or native for smoother feedback.
Direct access in desktop Chrome or Edge. About one report/sec on the tested Mac.
A local helper with about 50 reads/sec on the tested Mac. Supports Safari.
Checking sensor access…
The native helper runs on your own Mac. Follow the GitHub setup instructions, then run this from the downloaded project directory:
./scripts/run.sh
Open http://127.0.0.1:8768/, then choose Connect your MacBook → Use native reader. The hosted page cannot run the helper against your hardware.
Read frequency and hardware update frequency are different. The display does not smooth or invent angles.
Browser arrival and native read-completion times are separate; neither is a hardware capture timestamp. Native reads delayed more than 150 ms are discarded. Native mode requests up to 60 reads/s; repeated values may reflect the same sensor measurement.
No connection diagnostics yet.