Since a couple of years, engineering apps have been making their way to app stores. Mobile apps have been doubling up as testing and measurement (T & M) tools. If you have an Android phone with stunning sensors, Smart Tools Pro is an app that makes the most of them.

Home screen v1.5

Home screen of the app

Smart Tools Pro is a suite of tools consisting of a ruler, callipers, three types of protractors, spirit level, tape measure, distance meter, compass, magnetometer, flashlight, magnifier, decibel meter, and a contact vibrometer. For those who do not need all of them, each tool (named Smart Ruler Pro, Sound Meter Pro etc) is available as a standalone app for Rs 50 a piece. Smart Tools is one of the top selling apps on Google Play. It was among the apps put up for this year's Google Play sale. The free versions of the standalone apps come with ads and fewer features.


Protractors III, II and I

Smart Ruler Pro
This app consists of six tools –  a ruler, three protractors, spirit level and a thread pitch gauge. The ruler measures the length of any object placed along the length of the screen. Measuring the length of an object greater than that of the screen is tedious. You have to divide the length into many parts and moving the virtual ruler across the screen upsets the position of the guideline. You can use two guidelines like a pair of callipers. To measure an angle, hold the screen along the horizontal of Protractor I and drag the guideline until you reach the object. Protractor II is a clinometer. To measure slope, hold the phone along the incline. The third protractor is a goniometer. To measure the angle of a real-world, fixed object against which you can’t hold your phone (like the Leaning Tower of Pisa), point your camera in its direction. Choose Protractor III and set the guidelines (which, by the way, should tell you that the tower is inclined at 3.9 degrees with respect to the vertical). In case you are measuring the angles at night, you can switch the colour of the protractor visible on the screen to white. Keep the phone on a surface and the level gauge will indicate its flatness in terms of roll and pitch over a pair of cross hairs. Place a screw adjacent to the many markings on the thread pitch gauge to determine the pitch of the screw. Zero calibration can be done in one touch and you can switch between tools easily using a menu that pulls up.

Smart Measure Pro
This tool measures distance from an object in terms of metres or feet. It also measures the height and width of the object. The maximum measurable distance is 30.48 metres (100 feet). This tool takes a little practice before you can comfortably use it. Point the camera in the direction of the object from which you are trying to measure distance, set the crosshairs along the bottom and bring the spirit bubble to the centre. Once the distance is calculated, a ‘height’ button appears on the screen, which should be pressed to begin determining the height of the object. The readings could be somewhat inaccurate for a number of reasons including that the phone’s height is set to 0.3 metres (1 foot) subtracted from your height.

Smart Compass Pro
The compass displays the latitude and longitude, roll, pitch and a bar with the strength of the earth’s magnetic field. You can set it to point to the true north and turn on the rear camera for a background. You can also share your location details via email or Bluetooth. The Metal Detector tool displays the surrounding magnetic flux density in micro Tesla along a colour-coded indicator bar; x, y, and z space coordinates, and a running line chart that measures the flux density against time. If the flux density exceeds the maximum capacity of the phone’s sensor, it rings an alarm or beeps or sets up vibrations depending on the chosen settings.

Smart Light Pro
It’s a flashlight added on popular demand. It lights up either the screen or the device’s LED.

Smart Magnifier

The magnifier has zoom in and zoom out functions, an LED button and a function that limits your field of vision on the screen to a circle like a real magnifying glass. It also has an auto-focus touch button.

Sound Meter Pro
The decibel meter measures the ambient sound level by placing a pointer along a dial and also displays the numerical value in dB. Guidelines indicate the lowest, highest and mean values recorded. A running line chart at the bottom plots the decibel level against time. You can save and export the recorded graph of dB versus percentage. You can also access previously saved graphs. This app has nifty little functionalities such as a camera button that takes a snapshot of the screen. A list of decibel levels describes the corresponding ambient noise level settings.

vibrometer and magnetometer

Vibrometer (left) and magnetometer (right)

Vibration Meter

The contact vibrometer UI shows a line chart with a stylus that plots vibrations. It constantly updates the mean and maximum values. The tool can function as a seismograph. You can temporarily stop the line chart by touching the pause button, set its duration and change the baseline. It also shows eight degrees (I to VIII) of the Mercalli scale. We wonder why higher degrees weren’t included. One reason could be an upper limit on the capacity of the accelerometer; another could be that you aren’t likely to fire up your seismograph app when an earthquake of so high an intensity is occurring. The graph of the Modified Mercalli Intensity (MMI) is plotted against percentage. Like with the decibel meter, you can save and export graphs and view graphs saved earlier. You can adjust its sensitivity.

Design and layout
All the apps are laid out on the homescreen with icons for every meter and tool. The system of units – metric or imperial – is set from the homescreen. The UI is minimalistic and easy to use for all the tools. There is no trouble switching between landscape and portrait orientations.

Like with any measurement and calibration tool, the performance, sensitivity and accuracy of the tools in the app are determined by the hardware of the device. The sensitivity of the touchscreen could affect the placement of the guideline in the ruler and, by extension, affect the accuracy of the measurement. The hardware also determines the maximum or minimum possible measurable values. Also, some tools may not function if the phone or tablet lacks the required sensor. For example, the vibrometer would not work with a device without an accelerometer. Several tools do not work with the Nexus 7 for lack of a rear camera. If you intend to buy any of the tools as standalone apps instead of the composite app, do check if your device supports them. You can calibrate all the tools and adjust the sensitivity of some tools such as the vibrometer.

If you are someone who needs greatly precise and accurate measurements, you possibly carry your set of tools with you. For rough measurements and estimates, this app with its wide range of functions, variety of tools and a price of Rs 125, is immeasurably amazing. 

Smart Tools v1.5 was tested on the Sony Xperia go operating on Android Gingerbread.

Download Smart Tools for Android phones and tablets from Google Play.

Download standalone apps: Smart Compass Pro, Sound Meter Pro, Smart Measure Pro, Smart Ruler Pro, Smart Light Pro

Download free versions: Smart Compass, Sound Meter, Smart Measure, Smart Ruler, Metal DetectorVibration Meter, Smart Protractor, Smart Flashlight, Thread Pitch Gauge, Smart Magnifier

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