diff options
Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/README.md b/README.md new file mode 100644 index 0000000..5926409 --- /dev/null +++ b/README.md @@ -0,0 +1,37 @@ +## WALT Latency Timer ## + +**DISCLAIMER:** This is not an official Google product. + + * [Post about WALT on Android Developers Blog](http://android-developers.blogspot.ca/2016/04/a-new-method-to-measure-touch-and-audio.html) + * [Instructional videos showing how to use WALT](https://www.youtube.com/playlist?list=PLd6Fi7WgXfcCEJg1FDqNCoQfpWo7W3J5a) + * [Detailed usage instructions](docs/usage/WALT_usage.md) + * Mailing list - [walt-discuss](https://groups.google.com/forum/#!forum/walt-discuss) + * Low-traffic mailing list for major announcements [walt-announce](https://groups.google.com/forum/#!forum/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](docs/TapLatency.md) - 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](docs/DragLatency.md) (scroll). + * [Screen draw latency](docs/ScreenLatency.md) - using a photodiode that detects whether the screen is black or white. + * [Audio output and microphone latencies](docs/AudioLatency.md). + * MIDI input and output latencies + +The WALT app for Android can be +[installed from Google Play](https://play.google.com/store/apps/details?id=org.kamrik.latency.walt) +or downloaded in the [releases section](https://github.com/google/walt/releases); 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](android/WALT/app/src/main/jni/README.md). +* 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](https://chromium.googlesource.com/chromiumos/platform/touchbot/+/master/quickstep/). + |