user3840: I would like to extend my arduino uno with WIFI and I am checking different options.
These are:
Adafruit-CC3000-Breakout-with-Onboard-Ceramic-Antenna
Arduino WiFi Shield (integrierte Antenne)
Viewing the price, obviously I understand that the shield will have more functions, I think also it is more "friendly" for programming and the breakout requires more low level code(I am not afraid of it...)
I already have an arduino yun but it is busy with a project, so I need something for the uno.
For what kind of projects could be better each of them? and what are the main differences between a shield and a breakout?
Also in the future I would do some projects with gsm, so this question could be similar ... gsm shield vs breakout.

user3825: If you prototyping for a device intended for production then use breakout board with supposed WiFi module. Also if space is constraint then shield might be problem. For a hobby system use WiFi shield, which uses rather complicated circuit with AVR32 MCU, but you just plug-in and uses prooved libs. For production MCU would mean one more firmware flashing, upgrades, maintainance and higher price - from my point of view useless.

user313: A breakout board usually has the sole purpose of making a single chip (gross generalization here...) available to the experimenter by "breaking out" its signal lines on to dedicated pins - header pins, for instance. It is only large enough for the chip and the printed circuit wiring to do this, and seldom adds any function beyond what the chip itself provides.
A "shield" is a larger board that usually plugs directly onto an Arduino board, matches its form factor, and is built for a dedicated more complex function, like a complete GPS system or cellular communication system (although some shields are left mostly blank to provide you the space to build your own device). They probably have several chips engineered and built into a complete plug-and-go sub-system.
One is to learn to use a chip or other device without having to solder up your own board, especially with surface mount devices. The other is a ready-to-go system building block.

user368: Shields are in a form factor suited for direct attachment to the Arduino, but have fixed functionality for their connections. Breakout boards require more wiring work, but allow you to connect to any appropriate pins.

3840: <p>I would like to extend my arduino uno with WIFI and I am checking different options.</p>

<p>These are:</p>

<p><a href="http://www.exp-tech.de/Shields/Wireless/WiFi/Adafruit-CC3000-Breakout-with-Onboard-Ceramic-Antenna.html" rel="nofollow">Adafruit-CC3000-Breakout-with-Onboard-Ceramic-Antenna</a></p>

<p><a href="http://www.exp-tech.de/Shields/Arduino-WiFi-Shield-integrierte-Antenne.html" rel="nofollow">Arduino WiFi Shield (integrierte Antenne)</a></p>

<p>Viewing the price, obviously I understand that the shield will have more functions, I think also it is more "friendly" for programming and the breakout requires more low level code(I am not afraid of it...)</p>

<p>I already have an arduino yun but it is busy with a project, so I need something for the uno.</p>

<p>For what kind of projects could be better each of them? and what are the main differences between a shield and a breakout?</p>

<p>Also in the future I would do some projects with gsm, so this question could be similar ... gsm shield vs breakout.</p>
 3825: <p>If you prototyping for a device intended for production then use breakout board with supposed WiFi module. Also if space is constraint then shield might be problem. For a hobby system use WiFi shield, which uses rather complicated circuit with AVR32 MCU, but you just plug-in and uses prooved libs. For production MCU would mean one more firmware flashing, upgrades, maintainance and higher price - from my point of view useless.</p>
 313: <p>A breakout board usually has the sole purpose of making a single chip (gross generalization here...) available to the experimenter by "breaking out" its signal lines on to dedicated pins - header pins, for instance. It is only large enough for the chip and the printed circuit wiring to do this, and seldom adds any function beyond what the chip itself provides.</p>

<p>A "shield" is a larger board that usually plugs directly onto an Arduino board, matches its form factor, and is built for a dedicated more complex function, like a complete GPS system or cellular communication system (although some shields are left mostly blank to provide you the space to build your own device). They probably have several chips engineered and built into a complete plug-and-go sub-system.</p>

<p>One is to learn to use a chip or other device without having to solder up your own board, especially with surface mount devices. The other is a ready-to-go system building block.</p>
 368: <p>Shields are in a form factor suited for direct attachment to the Arduino, but have fixed functionality for their connections. Breakout boards require more wiring work, but allow you to connect to any appropriate pins.</p>
