The USB (Universal Serial Bus) is a standard that defines the cables, connectors and used a bus to connect, communicate, computers, peripherals and electronic devices protocols Transmission Rates Low speed (USB 1.0). Transfer rate up to 1.5 Mbit/s (188 kB/s) used in keyboard, mouse ... transfer rate up to 12 Mbit/s (1.5 MB/s) High Speed ??(USB 2.0): Rate transferencia up to 480 Mbit/s (60 MB/s) SuperSpeed ??(USB 3.0) transfer rate up to 4.8 Gbit/s (600 MB/s) Connector Types 1 - USB type A (4 pin) 2. - USB type B (4 pin) 3 - Mini A (5-pin) 4 - Mini B (5-pin) 5 - Micro A (5-pin) 6 - Micro B (5-pin)

or horizontal. The micro USB with five pins, which pins identification (ID) Micro AB USB connectors special work. AB connectors with pin ID can allow the device to function as a connector A or B to standard USB technology. This gives the new smart phones and other devices the option to act as either a single storage device or as provi

The mini USB connectors are smaller than their standard counterparts and have USB fifth pin. The fifth pin is known as the pin ID and is typically not used in mini USB connectors. It was designed to allow later improved USB technology. The mini USB connectors have a cycle life of at least 5000 connections and disconnections, which accommodates the mobile nature of the devices that are designed to interact. The standard USB connectors are generally used with devices that are stationary and not disconnected often.

The impedance (Z) is a measure of opposition that a circuit to a current when a voltage is applied. The impedance extends the concept of resistance circuits alternating current (AC), and has both magnitude and phase, unlike resistance, which has only magnitude. When a circuit is powered with direct current (DC), there is no distinction between the impedance and resistance; the latter can be thought csa impedance with zero phase angle.

USB 3.0 is the second major revision of the standard Universal Serial Bus (USB) connectivity for computing. USB 3.0 has transmission speeds of up to 5 Gbit/s, which is 10 times faster than USB 2.0 (480 Mbit/s). Connector Types 1 - USB type A plug 2 - 3 USB type A female - USB type B 4 - Micro USB B

USB-C reversible USB version called USB cables USB Type C Type C or USB reversible. The important thing is this type of USB is that it has top and bottom. So you may save the blows that are given involuntarily to connect the connector upside down. It is also characterized in that when connected will make an audible "click". The USB-C or reversible USB cables can reach 10 Gbps and support USB 3.0, 3.1Use is estimated up to 10,000 applications and has some measures 8.4mm x 2.6mm is also compatible with USB 3.1 and USB indicate creators

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).

for fine adjustments, in very small capacitance ranges.

Arduino is defined as a combined system between hardware and software, which allows users with or without programming knowledge to create projects from scratch. Thanks to its low cost and its wide range of accessories, it has become one of the most appreciated devices by the creative community or called makers (creators).

Within the Arduino range we can find different devices, which will allow us to easily create projects that perform different functions. Its open source GNU free access is essential in the maker community, which allows its creator to develop almost any prototype he can think of.

Arduino was created with the aim of reducing and lowering the material costs needed by interactive design students from Ivrea, Italy, since the devices they used previously were very expensive. This new Arduino project reduced the cost of the material each student needed and eventually became a commercial product as we know it today.

These small plates consist of a SRAM memory, with its own flash storage system (EEPROM), microcontrollers and a microprocessor, currently we can find different processors for the most current models, such as processors:

- 8-bit Atmel AVR
- 32-bit ARM Cortex-M0+
- 32-bit ARM CortexM3
- Intel Quark (x86) 32-bit

Arduino has an open source programming software called the Arduino IDE, with which anyone can create the basis of a new project. Both software and hardware are compatible with Windows, MacOS, and Linux operating systems. Its programming only requires a USB connection to the PC and the free programming software.

Among the different devices we can find the main Arduino board, the nerve center of any project, among which we can find:

- Arduino Uno R3
- Arduino Leonardo
-Arduino 101
- Arduino Explore
-Arduino Zero
- Arduino Mega 2560
-Arduino Due
-ArduinoMicro
- Arduino Nano
- Arduino MXR 2 UNO Adapter
- Arduino MKR Zero
- Arduino Yun
- Arduino Ethernet among others



In order to expand its functionality, we have a wide range of shields or modules that allow you to expand its functionality, such as screens, Wi-Fi modules, etc. these can be attached to the Arduino board itself, thus allowing it to read inputs and send data outputs. Among some shields we can find:

- Xbee wireless modules
- USB ports
- Sensors
- Breadboard
- Card readers
- WiFi connection
- Motors or servos
- Ethernet connection
- GPS module
- GSM module
- RS232 module
- Relays
- LCD screens
- Sound and DMX

Among some examples that we can create with Arduino and its external components we can find clocks, scales, alarms, automated irrigation systems, a battery tester, control of mechanical arms and much more.

Thanks to its large community of makers, we can find hundreds of projects to carry out on the net, ideal for delving into the world of electronics and programming, whether at an educational, professional or domestic level.