**No ads. No waiting. No stress.**

ZeroLevel is a spirit level app designed around one principle: stay out of your way.

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**[Simple. Ready the moment you open it]**
Measurement starts the instant you launch — no splash screens, no ads, nothing in between.
Hanging a shelf, leveling furniture, aligning a camera shot — built for that exact moment.

**[Two measurement modes, automatic switching]**
- 2D Mode (flat): Place your phone flat to see tilt in all directions at once. A bubble-style graphic makes it instantly readable.
- Landscape support: Rotate to landscape for a larger bubble display with angle values at a glance.
- 1D Mode (upright): Stand your phone upright to check walls and posts for true vertical. A bar-style graphic gives you a quick read.
Auto-detects your phone's orientation and switches modes — manual override available anytime.

**[Pro-grade calibration]**
Thick cases, camera bumps — fully compensated.
Back (flat) and side (upright) can each be zeroed independently.
Every measurement starts from a true zero baseline.

**[Hold mode for awkward spots]**
One tap locks the reading so you can check it at eye level.
A red border highlights the screen while locked — no guessing whether it's frozen or live.

**[Dark UI, always-on display]**
Bright daylight outdoors or dim workspaces — high-contrast fluorescent green on dark background keeps readings clear in any condition.
Screen stays on during measurement so the numbers are always there when you need them.

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**[Pro: Feel the level — without looking at the screen]**
Pro features are available as a one-time purchase to support development.

**Stepped audio guidance (unique to this app)**
Adagio → Andante → Moderato → Allegro → Vivace → Presto → Goal —
7 stages of rising tempo and pitch guide you to level without ever glancing at the screen.
A vibration fires the moment you hit the goal zone — double confirmation.

**3-level precision setting**
- High Precision (goal under 1°): For precise, millimeter-level work
- Medium Precision (goal under 2°): Perfect for everyday DIY
- Low Precision (goal under 3°): Quick rough alignment

Precision setting controls both the audio guidance cues and the "goal color" shown in the bubble and bar graphics.

Additional Pro features:
- Vibration feedback (can be toggled independently from sound)
- Multiple calibration profiles (up to 3, each with a custom name)
※ When 2 or more profiles exist, the active profile name is shown on screen at all times
- Raw sensor data display (accelerometer X / Y / Z axes)
- Battery saving mode (reduces sampling rate to minimize power consumption)

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**[Our approach to ads and purchases]**
This app is completely free with no ads.
Pro features exist as a way to say "thanks for building this" — nothing more.
No pressure. The free version is fully usable on its own.

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**Requires**: Android 5.0 (API 21) or later