Android Android is a kernel-based Linux operating system designed primarily for touch screen mobile devices such as smartphones or tablets, initially developed by Android, Google Inc. supported financially and later bought the company in 2005. IOS is a mobile operating system of Apple Inc. Originally developed for iPhone (iPhone OS), beingthen used in devices like the iPod Touch, iPad and Apple TV. Apple, Inc. does not allow the installation of third-party iOS hardware.

The Wifi technology is a wireless communication mechanism between devices. This technology allows you to connect devices such as computers, laptops, mobile etc... to the Internet or communicate with the devices themselves.

Applications can be several, among the most common are the access points, ideal for giving and sharing a connection signal to multiple devices. It is the typical configuration of a home user.
Repeater, ideal to repeat and amplify weak signal.

The power and range between devices basically depends on the antenna and its hardware.

The wireless signals work under a unified standard regulations, the standard that is based on the IEEE 802.11. These include IEEE 802.11b, IEEE 802.11g and IEEE 802.11n working at 11 Mbit/s, 54 Mbit/s and 300 Mbit/s, respectively.
Being any device with a standardized protocol such technology can connect to another using the same technology, making it a kind of universal connection.

The wireless networks are characterized by the ease and convenience of making connections in infrastructure, since it is not necessary to perform network cable installations.
it also allows connecting a lot of devices to a single node.

There are several ways to connect electronic devices to each other; cables, infrared, etc. Bluetooth technology is one of them and enabling wireless transmission of voice and/or data between devices by radio frequency.
It is a technology of radio waves at short range (2.4 GHz) whose objective is the communication between devices such as computers, smartphones, tablets, printers, headsets and other dispositives hand.
Bluetooth is called the communication protocol specifically designed for low-power devices. These devices can be classified according to their transmission power:
- Class 1: 100 mW, maximum range approximately 100 meters.
- Class 2: 2.5 mW, approximate maximum range between 5 and 10 meters.
- Class 3: 1 mW, maximum range approximately 1 meter.

We can also classify this technology by standard. All these versions have backward compatibility, ie, it allows the latest standard is compatible with all previous versions.

- Version 1.2: 1 Mbit/s
- Version 2.0 + EDR: 3 Mbit/s
- Version 3.0 + HS: 24 Mbit/s
- Version 4.0: 24 Mbit/s

When calculating the life of a battery it will be necessary to know the number of charge cycles that can be performed until the battery does not begin to lose its capacity.
Depending on the type of battery these charging cycles can vary, the most common being the mobile batteries, manufactured Li-Ion or Li-Po, which have a duration of between 300 and 500 charging cycles according to model and manufacturer.
Once thisE limit we will notice how the battery loses duration of operation, arriving to lose up to 25% of its capacity of load.
At this point it will be necessary to evaluate a battery change.
It should be noted that usage and charging habits can significantly affect battery life. For example, factors such as heat, charge the battery several times a day without it is almost exhausted, etc. Will be affectedits duration.
Therefore, to get the most out of the battery we must know when a full charge cycle is performed, and try to avoid misuse of charge, to increase its useful life.
A charging cycle is considered when the battery has been discharged or its 100% charge has been used.
The manufacturers advise that the charge is never made below the 58% battery, since the battery voltage would not fall so lowTo, so you could end up winning up to 4000 charge cycles.
Tips to increase the life of a battery.

• Avoid extreme heat or cold or very long applications of the device.
• Charge the battery as often as you can.
• Fully discharge the battery from time to time.
• Do not let the battery run out completely before charging.

Below is a table with theDifferent voltages (V), charge cycles (C) and battery percentage (B).