Smart Ruler Pro (ver 2.7) manual

Hello. I'm android boy, the chief developer of Smart Tools co,.

Smart Ruler Pro is the 1st set of Smart Tools suite. It is the collection of the 6 tools (ruler, 3 protractors, surface level and thread pitch gauge).


※ Introduction video



Ⅰ. Ruler : for length, by touch

single touch

multi-touch, horizontal x vertical ON

Ⅱ. Touch Protractor : for angle, by touch

single touch, multi-touch

Ⅲ. Plumb Protractor : for slope, by plumb

- zero calibration : click the icon to set to zero.

- locking plumb : touch anywhere on the screen. "Holding..." text will blink.

- screen capture

- auto-focus

Ⅳ. Camera Protractor : for tilt, by camera

- B/W : change the line and text color

Ⅴ. Surface level : for horizon, by balls

Ⅵ. Thread pitch : metric, US, NPT, BSPT, Screws

※ Menu & Setttings

- Scale option for maps and drawings. enter [Scale] at the settings.


※ Orientation sensor ??
Most protractors and level apps are using only an acceleration sensor. But, this way has a limitations. When the slop is bigger than 60 degrees, the result can be inaccurate.

This app provides the best solution. Orientation sensor!! It calculates tilt using both magnetic sensor and acceleration sensor. The result becomes more reliable. I recommend that you turn on this option. But some custom ROM and non-magnetic devices cannot activate orientation sensor. Please check your specifications.


※ Measure longer object than your screen (ruler)



※ Caliper mode (thread)

 touch the screen with 2 fingers

※ FAQ
Q. The default screen width is not correct.
A. Click [Calibrate] icon on the app bar. You can enter correct size (long-side, not diagonal) for yourself.

Q. The level does not work.
A. Some custom ROM and OS have this problem. Release [Orientation sensor] option at the settings.

Q. I cannot calibrate the level with zero-calibration
A. You have to reset all settings. Go menu > Settings > Reset settings.

※ What's new
  - v2.7 : Support for OS 11

  - v2.6 : Sound effect, new icon
  - v2.6 : Material design
  - v2.5 : Action Bar
  - v2.3 : Thread pitch gauge
  - v2.1 : Multi-touch
  - v2.0 : Smart Ruler Pro released (Oct. 2010)
https://play.google.com/store/apps/details?id=kr.aboy.ruler

If you have any idea to improve it, feel free to contact me. androidboy1@gmail.com
Thank you.

Smart Protractor (ver 1.5) manual

Hello. I'm Android Boy.

After releasing [Smart Ruler] for length measurement, I had to develop an app for angle measurement. This app has 3 protractor modes below (touch, plumb, camera).


※ Introduction video



Ⅰ. Touch mode

Ⅱ. Plumb mode

Ⅲ. Camera mode

※ How to lock the plumb?
In plumb and camera mode, touch anywhere on the screen. The red "Holding..." text will blink.


※ Menu & Settings

※ Orientation sensor ??
Most protractor apps are using only an acceleration sensor. But this way has restriction. When the slop is bigger than 60 degrees, the result can be inaccurate.

I tried to find a good solution with an orientation sensor!! It calculates tilt using both magnetic sensor and acceleration sensor. The result becomes more reliable. I recommend that you turn on the option [Orientation sensor] if possible.

Several custom ROM and devices without a compass sensor cannot activate orientation sensor. Please check the specifications and turn off this option.

※ Pro version additional features:
 1) 6 tools (ruler, level, thread) are integrated
 2) More Tilt units
 3) More languages supported
 4) No ads



※ What's new
 - v1.6 : Support for OS 11

 - v1.5 : Support for OS 10

 - v1.4.6 : Galaxy S6 support, Optimized on OS 8.0
 - v1.4 : Material design, camera mode
 - v1.3 : Action bar
 - v1.2 : New icon
 - v1.0 : Smart Protractor released (Sep, 2010)
https://play.google.com/store/apps/details?id=kr.sira.protractor

If you have any idea to improve the app, feel free to contact me at androidboy1@gmail.com. Thank you.

Thread pitch (ver 1.4) manual

Hello. I'm Android Boy.

Smart Ruler Pro included a thread gauge for screws, nuts and bolts. Several users required an individual app, so that I released this app for the experts who had a paper to measure thread pitch.


※ Introduction video



※ Screenshots

※ Multi-touch

Touch your screen with 2 fingers. You can choose background color at the settings.


※ Menu & Settings

※ Calibration
  - This app includes a database of 2000+ major android devices. If yours is a brand-new or unique device, please calibrate for yourself. Measure your ACTUAL screen width and input the number at calibrate menu. See the screenshot below.

※ FAQ
Q. I need more thread tables.

A. I'm not a hardware expert, so that I need standard documents. Please contact me at androidboy1@gmail.com.


※ Pro version additional features:
 1) 6 tools (ruler, 3 protractors, level) are integrated
 2) Screen lock/unlock
 3) More languages supported
 4) No ads



※ What's new
 - v1.4.7 : Support for OS 11

 - v1.3.3 : New icon
 - v1.3.2 : Galaxy S7 support, sound effect on/off
 - v1.3.1 : Material design
 - v1.3 : Screw sizes
 - v1.2 : Action bar
 - v1.0 : Thread Pitch released (June, 2011)
https://play.google.com/store/apps/details?id=kr.sira.thread

If you have any idea to improve the app, feel free to contact me at androidboy1@gmail.com. Thank you.

Smart Ruler (ver 1.6) manual

Hello, I'm Android Boy. Thank you for your visit.

Smart Ruler is the first app that I developed. It is in the 1st set of Smart Tools suite. When I tried to develop a distance-app, I saw a similar iPhone app. At the time, there was no such app in Google Play, so that I had developed it for 2 days. I have updated it for 5 years. :-)


※ How to use??
1) Put an object on the screen of your device.
2) Adjust its left edge to the left of the screen.
3) Touch the screen, and adjust its right edge with a red line. That's it.


※ Introduction video



※ Screenshots
1) single-touch

2) multi-touch

You can choose text and background color at the settings.


※ Menu & Settings

※ Calibration
  - This app includes a database of 2000+ major android devices. If yours is a brand-new or unique device, please calibrate this app on it. Measure your ACTUAL screen width and input the number at calibrate menu. See the screenshot below.

※ FAQ
Q. The screen width is not correct.
A. Click [Calibrate] icon on the app bar. You can enter actual size (long-side, not diagonal).

Q. I cannot touch my screen.
A. A wet finger or a conductive material may frustrate your touch.


※ Pro version additional features:
 1) 6 tools (3 protractors, level, thread) are integrated
 2) Horizontal x Vertical
 3) Architectural and Engineering Scales
 4) More languages supported
 5) No ads



※ What's new
 - v1.6.3 : Support for OS 11

 - v1.5.0 : More models are calibrated
 - v1.5 : Material design
 - v1.4 : ActionBar added
 - v1.3 : App2SD
 - v1.2 : Tablet PCs support
 - v1.0 : Smart Ruler released (June, 2010)
https://play.google.com/store/apps/details?id=kr.sira.ruler

If you have any idea to improve the app, feel free to contact me at androidboy1@gmail.com. Thank you.