gerrit-public.fairphone.software / platform / external / walt / 2e1d8eaca5b604d62bde90925c53ff1137e6a3ce
| commit | 2e1d8eaca5b604d62bde90925c53ff1137e6a3ce | [log] [tgz] |
|---|---|---|
| author | Bob Badour <bbadour@google.com> | Thu Mar 26 16:45:43 2020 +0000 |
| committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | Thu Mar 26 16:45:43 2020 +0000 |
| tree | 11af8e90dc3ca95b5850b8d5734e7cc2da37ba03 | |
| parent | 7af2b12b8bca1dca39cdb90407bf492206acfd0d [diff] | |
| parent | 99c3e76c447f8e9d95d74c1457c25532997005b5 [diff] |
Remove redundant NOTICE copied from LICENSE. am: 735624bc34 am: 99c3e76c44 Change-Id: Ia0e23e75291bad41819704dd811e3d9f7bbead3f
tree: 11af8e90dc3ca95b5850b8d5734e7cc2da37ba03
- android/
- arduino/
- docs/
- hardware/
- ios/
- pywalt/
- server/
- AUTHORS
- CONTRIBUTING.md
- CONTRIBUTORS
- LICENSE
- 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.