Saturday, April 2, 2011

What Exactly is an Arduino? 2nd post

Posted by rinson

The Arduino board is made up of an Atmel AVR Microprocessor, a crystal or oscillator (a crude clockthat sends time pulses at a specified frequency to enable it to operate at the correct speed), and a 5-voltlinear regulator. Depending on what type of Arduino you have, it may also have a USB socket to connectto a PC or Mac for uploading or retrieving data. The board exposes the microcontroller’s I/O(input/output) pins so that you can connect those pins to other circuits or to sensors.The latest Arduino board, the Uno, differs from the previous versions of the Arduino in that it doesnot use the FTDI USB-to-serial driver chip. Instead, it uses an Atmega8U2 programmed as a USB-toserial
converter. This gives the board several advantages over its predecessor, the Duemilanove. First,the Atmega chip is a lot cheaper than the FTDI chip, bringing the prices of the boards down. Secondly,and most importantly, it enables the USB chip to have its firmware reflashed to make the Arduino showup on your PC as another device, such as a mouse or game controller. This opens up a whole array ofnew uses for the Arduino. Unfortunately, moving over to this new USB chip has made it a lot more
difficult for clone manufacturers to make Arduino Uno clones.To program the Arduino (make it do what you want it to) you use the Arduino IDE (Integrated
Development Environment), which is a piece of free software in which you write code in the languagethat the Arduino understands (a language called C). The IDE lets you to write a computer program, whichis a set of step-by-step instructions that you then upload to the Arduino. Your Arduino will then carryout these instructions and interact with whatever you have connected to it. In the Arduino world,programs are known as sketches.The Arduino hardware and software are both open source, which means that the code, schematics,design, etc. can be taken freely by anyone to do what they like with them. Hence, there are many cloneboards and other Arduino-based boards available to purchase or to make from a schematic. Indeed,there is nothing stopping you from purchasing the appropriate components and making your ownArduino on a breadboard or on your own homemade PCB (Printed Circuit Board). The only caveat thatthe Arduino team imposes is that you cannot use the word “Arduino.” This name is reserved for theofficial board. Hence, the clone boards have names such as Freeduino, Roboduino, etc.
As the designs are open source, any clone board is 100% compatible with the Arduino and therefore any software, hardware, shields, etc. will also be 100% compatible with a genuine Arduino.