How to check the touchscreen on android. Checking a used Android gadget before buying

When buying a smartphone / tablet or out of a sense of their own curiosity, many users want to check the functionality of the device, the main functions and sensors.

The external state of the gadget can be assessed without additional utilities, but the "filling" requires a more thorough approach. The easiest way to test basic sensors and functions is by application. They are very convenient and easy to use, but there are two significant drawbacks:

1. Provide insufficient full information.
2. They do not work on all smartphones (for example, some Chinese smartphones understand only half of the queries).

Diagnostic programs

The developers offer a huge list of utilities with similar functions to check the performance of various sensors, Wi-Fi, Bluetooth, cameras, processors and much more. We have selected the most functional and useful ones and tested them on our experimental Xiaomi Redmi 2.

The order of software review is random. In general, the apps are equivalent, but Phone Doctor Plus has a slight advantage - it's simple and focused on.

The home screen displays general information about the device. To make them as comprehensive as possible, you need to go to the second tab, where more than 20 tests are located, including multitouch, accelerometer, GPS and much more (see screenshots). Each of them is performed separately, some ask you to do a simple action, for example, shake the phone or insert headphones. Upon successful completion, a green icon with a check mark appears - this means that the function is working correctly.

The program came from the computer sphere (Windows), where it managed to prove itself from the best side. The Android version is no exception, which is why it was included in our selection.

The main screen looks plain, there is not even a hint of a minimalist design. But we are not here for that, so let's move on to the functionality. AIDA64 provides information on the following points:

• System: device model, board, RAM, storage and more.
• CPU: exact processor model, technological process, bitness, number of cores, frequency range and, most importantly, load. If the latter is constantly striving for 100 percent, then either the smartphone is clogged and requires a complex one, or there are serious problems with the chipset.
• Display: All display data, including resolution, technology, diagonal, video accelerator and OpenGL version. Pay attention to the "GPU load" - it should only occur in games or when working with graphics. In normal mode, on the tested gadget, the indicator was at zero.
• Net: operator, country, provider code and other details. To check the connection, it is easier to just call someone and go to the Internet.
• Battery: charge level, battery status, temperature and capacity. For a detailed battery check, see.
• Android: version, API level, build ID, and so on.
• Devices: rear and front cameras with descriptions of features such as stabilization, auto exposure, flash and other functions. Comprehensive information about the video processor.
• Temperature components in Celsius ().
• Sensors. Lines with constantly changing numbers will appear on the screen. They characterize the operation of a gyroscope, compass, accelerometer and others. With a slight movement of the smartphone, the numbers should change. As a reminder, this is much easier to check with Phone Doctor.
• Applications... List installed games and programs.
• Codecs, folders, system files.

The main screen immediately presents a list of tests. Let's get started!

• Sensor status: by analogy with AIDA64, only more understandable in Russian. There are also properties for each of the sensors.
• Wi-Fi status: information about the connection, little useful.
• Telephony: operator, signal, provider code and other uselessness.
• GPS status: satellites, signal transmission accuracy, latitude, longitude, bearing.
• Battery: charge level, capacity, technology, voltage, temperature and battery status.
• Multi-touch test: touch the screen with all fingers, check the display. For this it is better to use.
• Camera: basic information, the previous program has a more informative and complete list.
• System information.

The instruction is relevant for Android smartphones version 4.2. This method suitable for most sony smartphones Xperia differences may vary depending on the installed android version.

Using the Adnroid service code.

One of the best ways to check touch screen on the Android smartphone is to use the built-in diagnostic tool. To do this, we need to launch the service menu, you can do this by typing a certain service code.

To dial this code you need to open the dial pad on your phone. home page phone in the lower corner of the display, press the call key.

We dial the following service code * # * # 7378423 # * # * or * # * # SERVICE # * # *. A menu will open that will allow you to customize your phone in more detail, check its parameters or run diagnostic tests. If, after entering the code, the menu does not appear automatically, try pressing the call button to execute the command. If nothing happens, this code does not work for your phone model.

After you have typed the code, a service menu will appear.

Selecting Service Tests
In order to diagnose the sensor, go to the Touch screen item. In our example, everything is obvious, on other phones the menu items may be named differently.

Click the Touch screen option and proceed to diagnostics.
You should see a black screen on your Sony Xperia... All you need to do is move your finger or stylus over problem areas of the screen. The screen shows all touch points and you can find areas in which the sensor does not respond or does not work properly. This checks the functionality of the touch screen.

What is a touch screen?
It is a thin transparent touch-sensitive film glued to protective glass phone screen. The exception is Samsung and Apple devices, they have a sensor film glued to the display itself.

When a broken glass is replaced in the phone, the touch screen is also replaced with it. Therefore, after you have replaced the glass, be sure to check the operation of the sensor.

To check the sensor, you can use the built-in function in Android OS. Who knows how to enable it, use it, who does not know - install a small program from the Play Store Screen Touch Test... Both of these programs leave a mark on the screen after you slide your finger across it.

To check the sensor, draw rectangle around the screenthen full screen cross through its middle, after that two diagonals from opposite corners. When drawing shapes, keep your finger on the screen and try to keep it as even as possible. It is important!

The sensor does not work correctly if, as a result of the test:
- the line was interrupted
- lines appeared, points that you did not draw
- the line is uneven, has significant splashes

After that, put your phone into standby mode, then turn it on and check if the sensor is responsive. If everything goes well after that, put the phone back on standby, call it and answer the call.

If this also works, proceed with the last operation. Go into the settings and without lifting your finger from the screen, scroll the list up and then down, then up again and hold your finger, the list of settings should freeze with your finger. If the list jumps up and down, the sensor is faulty.

Sensor malfunctions may not be permanent and do not appear immediately, therefore, a new sensor must be guaranteed at least 1 month, as a rule, this is enough. Do not change glasses or display modules in services where they are not guaranteed.

Touch screens (A touch screen is an input device that is a screen that reacts to touch. Wikipedia) are increasingly used in modern electronic technology. The vast majority of devices (about 90%) are now equipped with resistive touch screens.

The resistive touchscreen consists of a glass panel and a flexible plastic membrane. A resistive coating is applied to the panel and membrane. The space between the glass and the membrane is filled with micro-insulators, which are evenly distributed over the active area of \u200b\u200bthe screen and reliably insulate conductive surfaces.

When the screen is pressed, the panel and membrane are closed, and the controller, using the ADC, registers the change in resistance and converts it into touch coordinates (X and Y). In general terms, the reading algorithm is as follows:

A voltage of + 5V is applied to the upper electrode, the lower one is grounded. The left and right are short-circuited and the voltage across them is checked. This voltage corresponds to the Y-coordinate of the screen.

+ 5V and "ground" are supplied to the left and right electrodes, the X-coordinate is read from the top and bottom.

The above algorithm is for 4-wire screens.

But at one "beautiful moment" the screen looked like this:

We disassemble a device with a non-working screen. We are looking for a cable from the sensor (4-wire), for example, as in the photo below:

Based on the principle of operation of such a screen described above, the test method is reduced to measuring two touchscreen resistances. They should not be abnormal, that is, less than 50 ohms and more than 1500 ohms. In case of mechanical damage, the coating layer breaks and the resistance will be infinitely large. To do this, it is not necessary to break the screen, press down hard enough at the point of contact of the loop with the layers so that this contact moves away.

Those. we take an ordinary multimeter, set it to measure resistance up to 2 kOhm and try to ring the screen. In the absence of mechanical influences, two pairs of two contacts should ring among themselves (resistance up to 1 kOhm, usually 300 or 600 Ohms), and pairs of contacts SHOULD NOT ring between themselves (they call only when the screen is touched).

The rapid change in the dollar exchange rate has led to significant mobile gadgets. Today it is much more difficult to acquire new smartphone with decent technical characteristics, which is why more and more people are putting off their purchase for later or buying used devices. However, when buying from hand, there is always a danger of purchasing a device with breakdowns or a factory defect. In this article, you will find all the necessary tools to help you avoid the hassle of buying a used Android smartphone or tablet.

How to check the screen for dead pixels and other problems

The gadget screen is one of the most vulnerable parts of it. A close visual examination can determine the presence of cracks, chips, abrasions and other physical damage. But to identify defective pixels and problems with the touch, you will have to use special programs.

Display Tester

With the help of this program, you can detect various problems with the screen of a mobile device, including broken pixels or traces of the gadget in a liquid, which are detected only with a special test. In addition, the program will provide you with much more detailed information about the used display than you can find even in the most detailed technical description.

MultiTouch Tester

This program is well known and used by all testers of mobile gadgets. It will simply and visually show you how many simultaneous taps your device's touchpad supports. Particular attention should be paid to this parameter if you want to check whether they are trying to sell you a cheap fake under the guise of a branded device.

Yet Another MultiTouch Test

A much more powerful utility for checking the operation of the sensor, which allows you not only to find out the number of simultaneously recognized touches, but also to identify the "dead" zones of the touchscreen, if any. To do this, the program has a Paint Tester mode that allows you to draw on the screen. Just draw a grid on the screen and immediately see if all its zones have the same sensitivity.

How to check if Wi-Fi is working

Today, quite often you come across devices whose designers are striving for a spectacular appearance the gadget neglects the mandatory requirements for the layout of elements. For example, they shield the antenna of the wireless module with a beautiful metal edging, as a result of which such a smartphone or tablet can work only in the immediate vicinity of the router.

Wifi Analyzer

Wifi Analyzer will give you the opportunity to evaluate how your smartphone or tablet "sees" wireless networks and how well the corresponding path of the device is assembled and configured. In addition, you can at the same time find a free channel and determine the zone in your house in which the signal reception is the most confident.

How to find out the speed and accuracy of the GPS system

One of the most common problems you may encounter after purchasing a used gadget is the slow determination of your location. Accurate and quick determination of your coordinates depends on many parameters, including the chip used, Android version, firmware, and even the country of manufacture of the device. Therefore, we recommend that you pay special attention to this aspect when purchasing.

GPS Test

The main program for testing GPS performance, which must be installed on every smartphone. It will give you the ability to determine the time and number of satellites with which the device can establish a connection, the accuracy of positioning, the ability to work with different geolocation systems, the stability of the satellite capture and other important parameters.

AndroiTS GPS Test

A worthy competitor to the previous program, which has approximately similar capabilities. In addition to testing all the parameters of a smartphone with satellite geolocation systems, it can also be used as a regular tracker, since it has the function of recording your movements and is able to work not only with GoogleMaps, but also OpenStreetMap, BingMap and Yandex.Maps.

How to determine the health of the microphone, accelerometer, proximity and light sensors

Modern mobile gadgets are acquiring an ever more extensive set of sensors and sensors every year. Some of them are used only in certain situations or are necessary for the operation of certain programs, therefore, their breakdown or absence may not immediately catch the eye of an inattentive buyer. For a complete check of all sensors of the device, there are several special complex programs.

Sensor List

This program displays a list of all sensors that are in the device, as well as graphs of their values \u200b\u200bin real time. You can check the operation of the accelerometer, magnetic field sensors, orientation, temperature, illumination and so on, tracking changes in the signal coming from them depending on changes in external conditions. IN latest versions support has also been added for checking the battery status (temperature, voltage and percentage of charge). The Sensor List is perfect for showcasing your new phone's capabilities, as well as diagnosing hardware after a system update or restore.

Sensor Box for Android

If the graphs from the previous program seemed too boring and incomprehensible to you, then Sensor Box for Android will help you test the gadget's sensors in a more visual way. In fact, we have before us a collection of small utilities, each of which is designed to check one of the properties of a mobile device. For example, when checking the gyroscope, you will be prompted to roll a ball across the screen, the orientation sensor is tested in a virtual level, and the light sensor is demonstrated on a houseplant drawn on the screen.

Elixir 2

This is a real test lab for smartphones and tablets running Android. It will help you collect the most complete information about the sensors available in the device and their health. In addition, here you will find complete data on running processes, installed programs, operating system, shared libraries, and more.

The main feature of the application is the ability to create special widgets on the desktop that can show the change in the parameter you need in real time. A complete list of all Elixir 2 features would require writing a separate long article, so we recommend it to all users who need the most detailed information about mobile device, be sure to pay attention to this program.

Of course, the best helpers when buying a second-hand gadget from your hands are your attentiveness and common sense. Resist the temptation and remember that things that are too cheap tend to be too expensive afterwards. We hope that the programs presented in this review will help you avoid mistakes and finally make sure that your choice is justified.