Smart Protractor - Angle & slope measurement

Smart Protractor belongs to the first set of the Smart Tools collection.

This application is designed to measure both the angle and the slope of an object. It offers three distinct protractor modes.

1.Touch mode：for measuring angles. Place the object on the screen and then tap the display。

2.Plumb mode：for assessing slope. A weight indicator shows the inclination of your device。

3.Camera mode：functions as a goniometer and inclinometer, utilizing the device's camera view。

* Key features:

- Tilt units available in degree, percent, and radian

- Zero calibration functionality

- Option to enable or disable the orientation sensor

- Material design interface

* Pro version additional features:

- Ad-free experience

- Multiple tilt unit options

- Screen capture capability

- Includes ruler, level, and thread pitch tools

* Interested in more tools?

Consider downloading the packages Smart Ruler Pro and Smart Tools.

Thank you for your attention!

【Real Use Experience】Smart Protractor Tool Test Notes

1. Touch Mode: The Convenience and Limitations of Screen Protractor

When trying to measure the tilt angle of the mobile phone holder, align the edge of the holder with the screen baseline. The touch point is sensitive but affected by the screen reflection. In a direct sunlight environment, the reflection of the stainless steel edge causes the virtual protractor scale to be blurred, and the angle needs to be adjusted repeatedly. The measured value is 75.3 degrees, and the error compared with the physical protractor is ±1.5 degrees, which is acceptable for daily small object measurement.

2. Plumb mode: The savior of furniture installation

Use this mode to detect verticality when installing a bookshelf. The phone is close to the side of the bookshelf, and the gravity sensor instantly displays the tilt percentage. After finding that it tilts to the right by 2%, fine-tune it and finally control the error within 0.3%. However, it is easily affected by the thickness of the mobile phone case on the uneven wooden surface, and the bare phone measurement is more accurate.

3. Camera mode: A combination of virtual and real outdoor measurement

When measuring the tilt angle of the balcony railing, there is parallax between the virtual protractor line superimposed by AR and the actual railing. You need to step back 3 meters to get a more accurate reading, and the screen delay is about 0.5 seconds when moving the device, which is suitable for measuring static objects. The measured iron railing is actually tilted 5 degrees (drainage design), which is consistent with the property drawing data.

Actual pain point record

• Touch mode range limitation: the maximum measurement angle is 160 degrees, which cannot meet the measurement of some mechanical parts

• Plumb mode unit switching is cumbersome: you need to enter the third-level menu to switch radians/percentages, and shortcut keys are urgently needed at the construction site

• Camera mode focus problem: automatic focus causes the angle line to shake during close-range measurement, and it is recommended to add manual focus lock

• Free version advertising interference: pop-up ads are easy to touch by mistake during measurement, resulting in data clearing

Professional version value assessment

✓ Screenshot function: automatically mark timestamps when saving measurement results, which is convenient for engineering records

✓ Integrated ruler tool: no need to switch APP for sudden measurement needs (such as temporary need to measure screw spacing)

✘ Additional tool accuracy: the built-in level is less accurate than professional tools and is only suitable for civilian-grade detection

Usage suggestions

• Calibration tips: zero calibration on a flat glass table (it is recommended to use the hard plastic sheet left over from the phone film)

• Error compensation: take the average of three readings during measurement to reduce the deviation caused by hand-held shaking

• Environmental optimization: turn on the black and white inversion mode at night to enhance the visibility of the virtual protractor scale

As a student majoring in mechanical engineering, this APP replaces 60% of the basic measurement needs in class, but still relies on professional instruments in precision scenarios such as CNC machine tool debugging. The most practical scenario is to help the elderly at home detect the slope of the wheelchair ramp (the plumb mode measured 8.6%, close to the upper limit of the barrier-free standard of 9%), and contact the property management for renovation in time to avoid safety hazards.