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Tips to Minimize Eye Strain When Using Screens

Do you spend hours in front of the computer screen and end up with tired eyes? It is normal. We spend the day looking at screens (computers, cell phones, tablets, TVs …) that increase eye strain.

Next, we are going to see a series of tips that can help you reduce eye strain and headaches due to eye fatigue.

How to Prevent Eye Strain From Screen

The rule of 25

It is probably the most important advice to take care of the health of your eyes. It consists of taking a 25-second break every 25 minutes. During those 25 seconds we must separate the view of the monitor and look at a distant point that allows us to relax the muscles of the eyes.

The ideal is to look towards a point that is more than 5 meters from us. The rule is very easy to memorize, but somewhat more complicated to carry out. I recommend that you use an alarm or use a Pomodoro app so that you remember to pause every 25 minutes and not once a month.

Brightness and reflections on the monitor

The brightness of our monitor should match the lighting of the surrounding work area. A good way to set the appropriate level of brightness is to put a white image on the monitor, for example, the background of a web page, and move a few meters away.

Look at the monitor and see if it is lighting something in the room. If it illuminates any area, it is too bright, you will have to lower the brightness. If it looks dull and gray, it’s probably too dark and you’ll need to turn it up a bit.

It is also important to reduce reflections on the screen. To do this, try to place the monitor perpendicular to the closest window. Since this is not always possible, you can also choose to use an anti-reflective filter.

Position the monitor well

The computer screen should be at a distance of between 50 and 75 centimetres from our face. Also, the centre of the screen should be 15-20 degrees below horizontal eye level, this means you should be looking down a little bit in your work.

A good method to achieve this is to adjust the top edge of the monitor so that it is at the same height as your eyes. If you can’t adjust the height of the screen, put a pack of folios or books underneath to raise it.

Text size

This is usually a very subjective aspect because many people prefer to have very small text to be able to see more things at once. However, if we want to take care of our eyes, a good rule of thumb is to set a font size in which the text is three times larger than the smallest size that you can read (from your usual position).

Background and font colors

In terms of colors, the combination that least forces our eyes is a very light white or yellow background with black letters. But there is no problem using light text on a dark background either. Of course, you have to avoid intermediate color combinations, since they do not have enough contrast.

Take care of your eyes

If you wear contact lenses, your eyes have to work harder when looking at the screen.

In that case, I recommend using glasses once or twice a week, it will delay the appearance of eye fatigue. If you can’t, remove your lenses as soon as you get home.

If you wear glasses, use anti-reflective glasses. They cost just a little more, but you will greatly improve your eyestrain.

In all cases, including people who do not wear glasses or contact lenses, use artificial tear drops to improve the moisture of your eyes. When we look at a screen we blink less frequently, so the eyes dry out.

To fix it, use a moisturizing solution that hydrates your eyes.

Adjusts the color temperature according to the ambient lighting

It is better to use a warmer (yellowish) color temperature in dark rooms and a cooler (more bluish) color temperature in bright rooms.

Color temperature is measured in degrees Kelvin (K), on a scale that ranges from 1,000 to 10,000.

During daylight hours, it is best to keep the monitor at a color temperature of about 6,500K. And at night, we can make the screen warmer by lowering the color temperature to about 3,400 K.

Although most monitors allow you to adjust the color temperature manually, the easiest way to do it by software, since you can adjust the color temperature automatically based on the time of day:

Windows 10 already includes a feature that can be found under the name “Night Light.”

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  • Most mobile operating systems also incorporate similar modes (night mode, reading mode, etc.).
  • We can also use the free F.lux program, compatible with almost all operating systems.
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TUTORIALS

Auto Change Wallpaper on Android Automatically

Many Android smartphone owners don’t want to be commonplace. Having a device that is the same as the others, which works the same as the others, behaves the same as the others or that looks like any phone that can be found in an operator’s store, is not ideal for many people.

Therefore, the customization tips for Android devices end up being very successful. For those users who can’t (or don’t want to) spend money on buying a new device or swapping out the current model for a more modern one, a simple change in the way visuals are presented can make a big difference to the experience of daily use.

Therefore, in this post, we will show how you can automatically change the background of your Android smartphone, with the help of an official Google application.

After all, everyone has a wallpaper installed on their smartphone right now, and, perhaps out of laziness, we haven’t changed that wallpaper as much as we’d like.

With the tutorial in this publication, you will configure your mobile so that the wallpaper changes automatically, every day. Something comfortable that saves you time.

And without depending on your daily intervention. Also, these changes will occur based on the preferences you set. The setup process itself is quite simple and unknown to many people as they need this little-talked-about add-on from Google.

How to change the wallpaper automatically

To perform the trick, you need to download the Google Backgrounds app. It has a very useful feature that allows you to change Android wallpapers automatically, every day.

And it is not a feature that is so hidden from users, but most do not even know about this function, have not even heard of it, or even do not know where it is located on the smartphone.

To configure this feature, simply follow the steps below.

1. Download and install the Google Wallpapers application from the Play Store.

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2. Open the application and select any of the many categories available.

3. Select the item for the daily wallpaper and configure how you want the backgrounds to download.

Please note that the wallpaper will change every day and the wallpaper will be downloaded via Wi-Fi unless you specify otherwise. At some point in the future, these wallpapers will repeat as all the images within the category you chose were saved to your smartphone.

You can switch between categories to change funds.

Clever. With this little tutorial, you will be able to make the automatic change of wallpapers on your mobile in a matter of seconds. The Google Wallpapers app is completely free, ad-free, and weighs only 2.3 megabytes, so you shouldn’t have to worry about internal storage.

This way, you will forget about changing the wallpaper and seeing new images every day.

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TUTORIALS

Types of Keyboards: Advantages and Disadvantages

Until recently, all keyboards were very similar. Big and gray… Or well, there were also black ones. However, with the increase in popularity of mechanical keyboards, users have increasingly demanded more types of keyboards and when there were none, they have created them. Thus, little by little its form and variety has grown; and now we have keyboards of different sizes for all tastes and possible desks. Next, we are going to look at some of the most popular keyboard sizes.

Keyboard Layout

The 100% keyboard

Full-size keyboards are typical computer keyboards. They have four different areas separated by spaces with a total of 105 keys in the ISO (European) format.

The 100% keyboard

  1. On the left we have the area with the letters.
  2. In the middle the navigation area (arrows, page turn, etc.).
  3. On the right we have the numeric keyboard.
  4. At the top we have the function keys and the escape.

There are also keyboards that are larger than a normal Full Size because they have macro keys on the sides. Some even have screens …

The Logitech G19

The Logitech G19

1800-Compact

1800-Compact layout keyboards have the same number of keys as a full-size keyboard, but the layout is slightly more compact:

  • The arrow keys, instead of being separated, are below the Enter key.
  • The other navigation keys become above the numeric keypad.

1800-Compact

The result is a keyboard that has all the keys of a full-size keyboard, but takes up slightly less space.

TKL (Tenkeyless or 80%)

TKL keyboards are the second most popular keyboards. They are like full-size keyboards, but without the numeric keypad.

The TKLs are very popular because even being smaller than the Full Size they have all the alphanumeric, navigation and function keys in their normal position, so the learning curve is minimal.

Its size is around 80% to 87% of the Full Size , which has some advantages:

  • The first and most important is that they allow you to adopt a more ergonomic position in front of the keyboard.
  • There is more space for the mouse.
  • They are easier to store and transport.

TKL keyboards have are like a Full Size keyboard, but without the numeric part

Furthermore, they are very easy for manufacturers to design and build. Mind you, although they have fewer switches, they are typically not cheaper than their full-size variants.

75%

They are known as 75% keyboards those that have a certain key layout that allows them to obtain a size that varies between 70 and 75% of a full-size keyboard. Of course, they keep the top row complete with the function keys and the escape

75% keyboard with ISO key layout

75% keyboards are already more rare to see because they save space by modifying the layout of some keys that are used a lot like Insert, Delete, Home, arrows, etc. so they have a small learning curve.

60%

The 60% size keyboards, in addition to ditching the number pad and navigation keys, also lack the top row of function keys.

60% keyboard with ISO key layout

The functionalities of these missing keys can be accessed through the Fn key usually located at the bottom right of the keyboard. To activate the function of the F1 key we will have to press the Fn key + 1.

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60% keyboards, while saving significant space and weight, have a considerable learning curve.

40%

40% keyboards are the smallest keyboards that are still relatively usable.

The 40% keyboards also dispense with the row dedicated to numbers, leaving only the letters and modifiers. The numbers must be accessed through the Fn key or with special keys.

40% keyboard with ANSI key layout

At the moment, these keyboards have not reached the general public and if you want to get one you will have to assemble it yourself or order it on request.

Tenkey (numeric keyboard or number pad)

Dedicated numeric keyboards usually have 21 keys: the normal numeric keys plus the keys with special functions Escape, Tab, and so on.

Tenkey keyboard with 21 keys

They are the perfect complement to Tenkeyless or smaller keyboards, eliminating one of the weak points of a compact design without taking up permanent table space. Having a separate Tenkey also allows you to place the numeric keypad on the left side of the keyboard.

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TUTORIALS

How Does A Bluetooth Headset Work

In this post about wireless headphones, we are going to try to clear up concerns in relation to their operation, mainly for all those who try to understand something beyond its simple use to listen to music.

This is something very interesting that helps us to have more information when buying a wireless headset and know what to take into account.

In the same way, we are going to talk about a feature that several models of headphones today include in order to provide better practicality in everyday use: wireless headphone technology called Bluetooth.

In recent times, wireless technology in headphones gained a significant following thanks to smartphones that lost the P2 (3.5mm) input for the headphones. At the same time, there was a greater popularization of the most affordable headphones from Chinese companies, which is why today it is simpler to buy a Bluetooth headset.

In today’s market, we find more than one type of wireless headphone technology, although the most popular and efficient today is Bluetooth. Due to this, we will analyze below what Bluetooth technology is, how it works and how it is applied in the audio of our headphones.

How Bluetooth Technology Works

Bluetooth wireless technology uses radio waves to connect different types of gadgets such as laptops, smartphones, and tablets.

Bluetooth makes use of radio frequencies, more specifically the 2.45 GHz frequency, and as this frequency band is widely used, it is a requirement to ensure in some way that Bluetooth does not suffer interference and that it does not produce them either. For which, they took advantage of the communication by FH-CDMA (Frequency Hopping – Code Division Multiple Access), which allows the moderation of the interference indices, dividing the frequency into 79 channels (or 23, subject to each country).

Differences between Bluetooth 4.2 and 5.0

The first thing we notice in Bluetooth 5 is that the range was optimized. While version 4.2 has a range of up to 50 meters in an open environment and up to 10 meters in an indoor environment (with walls), version 5 manages to provide a range of up to 200 meters in an open area and up to 40 meters in a closed environment.

This increase in range potential is due to the fact that Bluetooth 5 provides a changing transmission speed. It manages to use 4 levels of data transmission and is regulated according to the requirements of the gadget being used.

You can automatically switch between the following transmission speeds: 2 Mbps, 1 Mbps, 500 kbps, and 125 kbps. The lower the data rate, the greater the distance reached in data transmission.

For example, smartwatches do not need to send a large amount of data and consequently accept a transmission speed of 125 kbps, providing a range of up to 200 meters in an open environment. However, when a large continuous stream of data such as 1 Mbps or 2 Mbps is required as is the case with wireless headphones, for example, the range is greatly reduced. But do not worry, Bluetooth 5 will allow you to walk quietly throughout your house without great losses depending on the kind of Bluetooth you use (which is different from the Bluetooth version).

The second feature that stands out in Bluetooth 5 is battery saving. It manages to standby for a longer time and consume less power than its past generation (4.2). This is made possible by the enhancement of Bluetooth Low Energy (BLE) technology that was introduced in Bluetooth 4.0. It was created thinking about applications that require low data transfer (less than 1 Mbps) and for that, it uses the GFSK (Gaussian Frequency-Shift Keying) modulation system.

Finally, another feature that draws attention to version 5 of Bluetooth is the ability to transmit data in a single packet. In Bluetooth 4 this rate is 31 bytes per packet, while in Bluetooth 5 this value increases to 255 bytes per packet.

How to use Bluetooth 5.0 on technology devices

You will need a smartphone, tablet, notebook or other devices that support Bluetooth 5.0 and a headset that supports that version of Bluetooth. Both devices must be compatible with the technology to be really used, otherwise, the mobile will use an older Bluetooth version.

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Bluetooth classes

To make it possible to adjust Bluetooth to the most varied types of devices and purposes, the maximum range of the technology has been divided into four classes:

Class 1: Maximum power 100 mW (milliwatts) range up to 100 meters;

Class 2: Maximum power of 2.5 mW, range up to 10 meters;

Class 3: Maximum power of 1 mW, range up to 1 meter;

Class 4: Maximum power of 0.5 mW, range of up to 50 centimetres.

Bluetooth profiles

Bluetooth profiles are protocols that define what functions can be performed by devices that have Bluetooth.

There are currently around 40 different profiles, but some of these are found more frequently on devices that have this technology. The most relevant Bluetooth profiles for us will be presented below:

Advanced Audio Distribution Profile (A2DP)

This profile is responsible for transmitting audio from one Bluetooth device to another. It is used by all Bluetooth headphones and speakers today. Before the creation of this profile, Bluetooth audio was very grainy and only headsets were used for phone calls. The Bluetooth modules that support the A2DP profile have in them a set of audio codecs that can be executed according to the hardware capabilities. These codecs are designed to balance the needs for power use, audio processing, and sufficient data rates according to what is required.

Headset Profile (HSP)

This profile provides the ability to stream audio through the microphone to answer calls, and adjust the sound volume level. It is used together with the A2DP profile to be able to transmit the audio of the voices.

Handsfree Profile (HFP)

This profile gives the Bluetooth device the ability to make hands-free audio calls in cars or smartphones. Add features such as accepting, rejecting or ending a call without needing to touch, for example, on the mobile phone to execute the command.

Audio / Video (A / V) Remote Control Profile (AVRCP)

This profile allows the user to control the music or sound of the Bluetooth device by performing functions such as play/pause, forward / backwards; beyond controlling the volume. It is generally used in conjunction with the A2DP profile to enable sound transmission and control.

Audio codecs

The codec determines how Bluetooth will transmit data from the source to the headphones. Encodes and decodes digital audio data in a specific format. Thinking of an ideal situation, the data is transmitted through a high fidelity signal at the specified minimum bit rate. This will use less band while maintaining good playback quality, better distance capacity, and better headphone battery life.

Before we begin, it is important to say that to get the quality of the desired codec, both the source and the headphones must have support for that codec. Furthermore, it is also necessary to know the meaning of some terms to make it easier to read about the codecs below.

Basic codec terms

  1. Sample rate (Hz): is the number of data points per second in an audio file. You need two samples to accurately capture any frequency, so the audio is sampled at least twice the limits of human hearing (approximately 20 kHz). The sampling frequency of the CD is 44,100 Hz, which means that with every second of sound, 44,100 measurements of the signal’s voltage variation are taken. In this way, the higher the sampling frequency, the more accurate the representation of the signal. A higher sample rate means a larger file size.
  2.  Bit depth (-bit): is the number of bits saved for each audio sample. A sample represented by only one bit could receive only two values: “0” or “1”. On the other hand, a representation with 3 bits could receive 8 different values ​​(23 = 8): 000, 001, 010, 100, 110, 101, 011, 111. A CD has a resolution of 16 bits, which allows a binary resolution with 65,534 (216) values. A higher bit depth records a signal more accurately. A higher bit depth multiplies the file size.
  3. Bit rate per second (kbps): generally measured in kbps or Mbps. That’s the amount of audio data transferred per second, in our case via Bluetooth.

SBC codec (Low-complexity sub-band codec)

The simplest existing codec is the Low Complexity Subband Codec (SBC). It is present in all Bluetooth devices that have the A2DP profile, being a universal codec. Its transfer rates reach up to 345 kbps, enough to play compressed MP3 files. So in case you want high-fidelity audio, don’t expect too much from this codec.

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AAC (Advanced audio coding) codec

The AAC codec was developed by Bell Labs, Fraunhofer Institute, Dolby Labs, Sony, and Nokia. It is the standard format for iPhone, iPod, iPad, Nintendo DSi, Nintendo 3DS and PlayStation 3. It is compatible with PlayStation Vita, Nintendo Wii, Sony Walkman, Android and BlackBerry.

The codec can provide a data transfer rate of up to 250 kbps. But despite having slightly lower performance, AAC is widely praised among compression algorithms and is considered a breakthrough over the SBC codec.

Apple has chosen to adopt the AAC codec for all its devices, in addition to the SBC codec, which is a requirement to have the Bluetooth A2DP profile. Apple Music streams with AAC natively, making it the best choice for an AAC or ALAC file library. For best results, you should pay attention not to use your iPhone to stream other compressed audio formats. The compressed files in MP3 or Ogg Vorbis format Spotify must be decoded by the iPhone and then encoded in AAC before they are transmitted to the headphones.

AptX codecs

The aptX codecs were developed by Qualcomm with the aim of offering a quality that was close to that of a CD, offering a rate of 16bits / 48KHz with a data transfer rate of up to 352 kbps. Even in this way, aptX still adds lossy file compression, compromising the final sound quality.

The aptX HD was created specifically to obtain higher resolution audio and fewer losses than the first version. It is a codec capable of reaching a speed of 24bits / 48kHz in LPCM (Linear Pulse Code Modulation) with a data transfer rate of up to 576 kbps. This already provides significant gain compared to aptX or SBC in terms of sound quality.

To decrease audio latency in Bluetooth headphones, aptX Low Latency was created, thus enhancing gaming and video experiences. It is a codec that has a latency of fewer than 40 milliseconds with a data throughput of up to 420 kbps.

And finally, to improve the battery consumption of the headphones, Qualcomm has developed the aptX Adaptive codec that changes the data transfer speeds according to what the file that is being played requires. This codec supports a data transfer rate of up to 420 kbps.

LDAC codec

Sony, in order to achieve the best sound quality in the Bluetooth headphone market, has created its own codec called LDAC. It has the ability to vary the bit rate according to the definition of the song and is capable of maintaining a speed of 96KHz / 24bits with a data transfer rate of up to 990 kbps. This data transfer speed is almost twice that of aptX HD and three times that of SBC. Fortunately, in the case of LDAC, it is possible to find non-Sony Bluetooth devices that support this codec. In this way, you will be able to obtain an audio quality superior to the aptX HD codec.

UAT codec

Hiby has recently developed its own codec, Ultra Audio Transmission (UAT), to overcome all the barriers of the existing ones, including Sony’s LDAC, and has managed to achieve a sampling rate of 192 kHz with a data transfer rate of 1200 kbps. There are still few devices compatible with this technology, but it is something surprising and that raises the quality that we have in our Bluetooth headphones even more.

How to use the best possible audio codec

Even in the case of Bluetooth 5.0, you will need a smartphone, tablet or laptop, and a headset that supports the desired codec (either aptX, LDAC or UAT). Both devices will need to be compatible with the technology to be really used, otherwise the mobile will use the SBC or AAC codec, which are inferior in terms of audio quality when compared to the other codecs mentioned.

Bluetooth does not support high-quality audio when the microphone is in use

When only the earphone is used to listen to some sound, the A2DP profile is activated and consequently, you are able to use codecs such as aptX HD, aptX Low Latency, LDAC, etc.

However, when you need the microphone, the Bluetooth profile will change to HSP (Headset Profile) or HFP (Handsfree Profile) and this will cause the audio quality to drop sharply because Bluetooth does not have enough bandwidth to maintain the audio quality and at the same time send data from the microphone.

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This problem of lack of data transmission capacity can be improved with the use of Bluetooth 5.0 which has several improvements in terms of speed and data transmission capacity.

Apple W1 chip

Apple has a chip inside their headphones with a specific audio codec that can only be used on Apple devices. In case you do not have, for example, an iPhone and want to pair the AirPods on your Android smartphone, you will not get the same sound quality.

Also, if you have a better Bluetooth headset than Apple’s with support, for example, the LDAC or aptX HD codec, and you want to connect to an Apple device, it will unfortunately not be possible to benefit from these codecs. Your headset will use the SBC and AAC codecs which are simpler and low in quality compared to the other currently existing codecs.

Advantages and disadvantages of wired and wireless headphones

After all that has been talked about, you may have realized that Bluetooth technology in wireless headphones is by no means simple, requiring a lot of engineering and skill from both the source and the headphones themselves. All the development of Bluetooth versions and profiles, plus audio codecs, comes at a great cost.

In addition to having a cost in terms of technology built into the Bluetooth device, we still have the cost of the battery to keep the hardware working, the Bluetooth radio wave receiving antenna and the integrated chip with DAC and amplifier inserted inside the Bluetooth headphones. .

Unfortunately, this raises the price of a good wireless headset considerably. So do not fall into the mistake that cheap headphones of this type will offer you good quality since it is a challenge to balance the cost of Bluetooth technology with the sound quality of the headphones and with the quality of the materials used in the headset. manufacturing.

The Bluetooth headset, despite its high cost, makes it much easier to play sports by listening to music or a podcast, watching movies without disturbing others, or simply studying. All this without cables. However, if you prioritize sound quality above all else, it is interesting to consider the alternative of wired headphones over Bluetooth, since this technology has its limitations.

In terms of audio quality, regardless of the value, we still have some compression and degradation of the audio in headphones that work with Bluetooth technology compared to those with a cable. It also adds the audio latency problem that many wireless models, depending on the codec and the version of Bluetooth, still have.

In short, the wireless headphone market is constantly evolving and getting better and better. In the meantime, it will only be possible to obtain higher quality at a high cost, so it is important to weigh priorities.

In the future, the cost of the technology is likely to decrease, as well as an improvement in it. Meanwhile, you will hardly achieve the sound quality of a wired headphone. Just look at the headphones from the best manufacturers, none who intend to produce the best headphones in terms of quality are using Bluetooth technology. By contrast, all aspiring headphones have cables.

Does the device affect the quality of the Bluetooth audio?

If we were using the same audio codec, it will not affect the audio quality to use a different mobile phone (or laptop or tablet), model. This occurs because the function of the Bluetooth signal transmitting devices is only the transmission of the digital signal that has to be converted to the Analog signal so that the headset can emit sound.

Conversion of the transmitted digital signal (via an audio codec such as aptX HD or LDAC) and further amplification occurs within the Bluetooth headset, via an integrated circuit board that has a DAC and a system amplification.

That is if your smartphone has support for the aptX or LDAC codec and your Bluetooth headset has to support the same codec, the headset will sound the same even if you use another phone model (which also has support for the same codecs).

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