DragTree

DragTree is a reaction-time game built on a real NHRA Christmas Tree (the drag strip starting lights). Watch the ambers, react to the green, and see how fast you were. Beat your best, or beat a friend.

Launch it however you like:
• Motion sensor — mount the phone in the car, stage, and drive off. The app detects the launch and times it from the start of acceleration. No tapping.
• Tap — a big on-screen button.
• Hold to Launch — hold the button through the tree and let go on green, like a trans-brake button.
• Volume buttons and remotes — use a volume button, a wired headphone button, or a cheap Bluetooth camera-shutter remote as your launch button (Settings, off by default).

Fully offline — no internet, no account, no ads, no tracking.

TWO PLAYER
Put the phone between two people. Each gets their own lane and light; best reaction wins, and a red light loses.

TREES
• Pro Tree (.400) — all three ambers together, green 0.400 s later
• Sportsman Tree (.500) — ambers count down one at a time, green 0.500 s after the last

GRADES
Perfect (under .050) · Pro · Great · Good · Late · Red Light, which shows how early you went.

TRACK YOUR PROGRESS
• History of your last 30 runs, personal best, and a trend chart
• Consistency stats: average, spread, how often you land within ±.020, and your streak
• Series mode: 3, 5 or 10 runs back to back with a summary
• Time-slip comparison: enter the reaction time from a real slip and see how your phone differs

BUILT FOR PRECISION
• The motion sensor is read up to 200 times a second with the sensor's own timestamps, on phones with or without a gyroscope
• Accelerometer test: records 5 seconds of background vibration and suggests the most sensitive setting it won't trip
• Phone latency check: screen rate, sensor rate and a tap test, so you know how much of a time is the phone
• Three sensitivity presets plus a custom setting

Optional sounds: a tick on each amber, a beep at green and a chime for your result.

The reaction time shown is how quickly you responded after the green. A track time slip also includes the car's rollout and drivetrain response, so DragTree is best for practice and consistency, not for predicting your exact slip.

PERMISSIONS
• HIGH_SAMPLING_RATE_SENSORS — fast motion-sensor readings
• VIBRATE — touch feedback
• MODIFY_AUDIO_SETTINGS — plays the sound effects
There is no internet permission at all, and no microphone, location or storage access.