To understand the arduino you should understand what is the single chip microcomputer first, the basis of the arduino platform is AVR microcontroller instruction set.
1 What is a single chip?What's the difference between it and personal computer?
A computer can work to have such a few parts: central processing unit CPU(Operation, control),Random access memory RAM(memory data),Memory ROM(memory program),input/output devices/IO(Serial port, parallel output, etc).these parts are divided into several chips,installed on a printed circuit board called mainboard, but these parts are all made in a piece of integrated circuit chips named single chip.
2.What's the use of single chip?
In practical work is not any occasion needed computer has high performance,is there any reason for refrigerator to use core processor?the key of application is to see whether function is enough,if there is a good price performance ratio?
Single chip commonly used in industrial production related to program and control in the life such as Electronic organ, refrigerator, intelligent air conditioning.
Arduino is a set of tools used to sense and control l the physical world,It consists of a hardware platform based on single chip microcomputer and open source, and a set of program development environment for the Arduino board.Arduino can be used to develop interactive products.For example, it can read a lot of switch and sensor signals,control all kinds of lights, motors, and other physical devices.Projects can be alone, also can at run time and you run the program in the computer communications.Arduino projects can be alone, also can communicate with your program (flash,Processing，MaxMSP).You can choose to manual assembly or buy already assembled,Arduino open source IDE can be downloaded for free.
4.Why do you want to use Arduino?
There are a lot of single chip and single chip platform is fit for design to be used for interactive systems.For example,Parallax Basic Stamp， Netmedia’s BX-24，Phidgets，MIT’s Handyboard and so on.All of these tools is an easy to use toolkit., you don't need to care about single chip programming tedious details.Arduino also simplify the process of work with single chip, but compared with other systems Arduino has more advantages in many places,Especially suitable for teachers, students and some amateurs to use:
Cheap- Compared with other platforms, the Arduino board is quite cheap,The cheapest version of the Arduino can be made by yourself, even the assembled product, the price will not exceed 40 dollars.
cross-platform - The Arduino software can operated on Windows，Macintosh OSX and Linux operation system,.Most other single chip system can only operated on Windows.
Simple programming environment -Beginners can easily learn to use the Arduino programming environment,It can offer enough advanced application for advanced users as well.
Open source software and can be extended- The Arduino software is open source, for experienced programmers can extend it.Arduino programming languages can be extended by c + + library,If someone want to go to understand the technical details, you can skip the Arduino language using AVR C programming language directly (because Arduino language is based on AVR C),Similarly, you can also add AVR - C code into your Arduino program directly
Open source hardware and can be extended- Arduino board based on Atmel ATMEGA8 and ATMEGA168/328 single-chip.Arduino based on Creative Commons license, so experienced circuit designers can design your own needed module to extend or improve it. even for some relatively no experience of users, can also through testing board to understand how the Arduino work, save money and save trouble.
Digital I/O digital input/output port 0-13
Analog I/O digital input/output port 0-5
Support ICSP download,support TX/RX
The input voltage: USB port power supply or outer power supply 5- 12 V
Output voltage:support 3.3V,5v dc output
Processor: use the Atmel Atmega168 328 processor, because of its numerous supporters,Company developed a 32-bit MCU support arduino platform.
* Moved by moderator. *
[sorry but I had to switch the bold off too - that was close to 100% illegible otherwise! - Cliff]