(2014-05-02) Arduino UNO Rev3 ($28.49)
The Arduino UNO R3 is a board based on the ATmega328.
The latest incarnation of the original Arduino UNO
is the third revision, released by Arduino in 2012 (pictured at left).
The metal connector in the upper left is a full-sized USB "Type B"
which allows the Arduino to take on the role of a peripheral device
connected to a computer via a standard USB cable.
(2014-05-02) Arduino Leonardo ($25.64)
A microcontroller board based on the ATmega32u4 (with built-in USB).
For the Leonardo (and Micro) Arduino boards, USB communications are handled
by the main microcontroller.
This solution is less costly, and possibly more flexible,
than the design of UNO boards (featuring a separate ATmega8U2 or ATmega16U2 processor
dedicated to USB communications) but some lack of compatibility occurs because of
different interferences of USB communications with other tasks.
The upside (reportedly) is that the greater flexibility could allow you to turn
an Arduino project into a true plug-and-play USB device.
The main downside is that resetting the board will abruptly break USB communications,
leading to a condition which may or may not be easy to recover from.
(2014-05-02) Chameleon by André LaMothe ($59)
An Arduino clone with a Parallax Propeller on a single board.
This powerful board can be programmed in BASIC, C/C++ or assembly language.
The Arduino part is based on an
Atmel AVR 328P
and comes pre-programmed with the Arduino bootloader,
which makes it 100% software-compatible with the Arduino UNO.
As the I/O headers are not aligned the same way as on a genuine Arduino board,
the Chameleon is heralded as "95% I/O compatible" with Arduino.
The mechanical incompatibility means that you simply won't be
able to use most of the ready-to-plug shields made for the Arduino UNO,
which connect to some pins and transmit the others for use by other stacked shields.
(2014-05-03) Cheap Arduino Clones
Avoid buying a clone as your first "Arduino-compatible" board.
The Arduino® name is protected but
the hardware and the software are not, so they can be cloned and sold by anybody under
any other name (usually ending in "-duino").
Most manufacturers produce quality clones, some don't.
There are also dishonest people who counterfeit the Arduino name and trademarked graphics,
which (unlike mere cloning) is highly illegal.
With a genuine Arduino, you'll only be faced with the normal learning process,
without having to troubleshoot a system which you're not yet familiar with.
Some cheap imports are not even pre-programmed with the Arduino bootloader,
which makes them unusable to most people. Another serious issue is the lack of fusing
on the USB link, which fails to protect the host computer in unusual circumstances.
Otherwise, the clones are a cost-effective way to duplicate projects developped in the
comfort of a genuine Arduino environment.
Purchasing at least one genuine Arduino board is also a good way to support the whole Arduino project.
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