gerrit-public.fairphone.software / platform / external / walt / d1f48d2d84bf15fd07f48803b39a4ff0235a4641
| commit | d1f48d2d84bf15fd07f48803b39a4ff0235a4641 | [log] [tgz] |
|---|---|---|
| author | Tai Kuo <taikuo@google.com> | Thu Jul 30 18:35:12 2020 +0000 |
| committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | Thu Jul 30 18:35:12 2020 +0000 |
| tree | 00e0f9517f22f9f9fc95aa6a242a072f9b188f09 | |
| parent | 55e9a490afda2fe05499520c50dbdb2d2eb83a5b [diff] | |
| parent | 26b4ade211075ab524c99a8d4e68c8593b7d8457 [diff] |
pywalt: fix stuck communication am: de48cf557f am: 842e8b8860 am: 26b4ade211 Original change: https://googleplex-android-review.googlesource.com/c/platform/external/walt/+/12239743 Change-Id: I77f31433d5b4987b3594e065d937aff80f797b84
tree: 00e0f9517f22f9f9fc95aa6a242a072f9b188f09
- android/
- arduino/
- docs/
- hardware/
- ios/
- pywalt/
- server/
- AUTHORS
- CONTRIBUTING.md
- CONTRIBUTORS
- LICENSE
- METADATA
- MODULE_LICENSE_APACHE2
- OWNERS
- README.google
- README.md
README.md
WALT Latency Timer
DISCLAIMER: This is not an official Google product.
- Post about WALT on Android Developers Blog
- Instructional videos showing how to use WALT
- Detailed usage instructions
- Mailing list - walt-discuss
- Low-traffic mailing list for major announcements walt-announce
WALT is designed to measure the latency of physical sensors and outputs on phones and computers. It can currently perform the following measurements:
- Tap latency - time from the moment a finger-like probe touches down (or up) on the screen until the kernel timestamps an ACTION_DOWN (or ACTION_UP) event. This physical contact with the screen is timed using an accelerometer mounted on the probe.
- Drag latency (scroll).
- Screen draw latency - using a photodiode that detects whether the screen is black or white.
- Audio output and microphone latencies.
- MIDI input and output latencies
The WALT app for Android can be installed from Google Play or downloaded in the releases section; the iOS app must be built from source.
Notes
- Hardware build instructions can be found in this repository under
hardware/. - Clock synchronization details are described here.
- The Android/iOS device and Teensy clocks have a tendency to diverge due to differing clock frequencies. This means they will go out of sync after several minutes. The workaround is to use the app to re-sync the clocks. Some, but not all tests in the app will sync the clocks when starting a measurement.
- Python code used to communicate with WALT from Linux and ChromeOS can be found here.