Can a product created using Arduino be proprietary?-must source code be released

Here is a simple question. It seems to me that Arduino has vast potential to be used as a prototyping platform for a commercial product. After nearly 4 hrs. of researching about the GNU GPL (The GNU General Public License v3.0 - GNU Project - Free Software Foundation), I still haven't answered my own question: can a commerical, proprietary product be created using Arduino?
And if so, does the source code for the product have to be released, or can it remain proprietary? Does it [your product and "sketch," or source code] fall under the terms of the GPL, LGPL? And if so, which version of the GPL (it would be GPL 2 from what I can tell, if it falls under this at all).

It seems to me that if one uses an Arduino, or Arduino-compatible device to create a stand-alone piece of hardware, they CAN commercialize and sell their product without releasing their sketch source code, but I am not 100% sure. One particular sentence in Wikipedia, here (GNU General Public License - Wikipedia), under the heading "Use of Licenses Software," catches my attention and supports my conclusion. It says, "Software under the GPL may be run for all purposes, including commercial purposes and even as a tool for creating proprietary software, for example when using GPL-licensed compilers." This means that using the Arduino IDE does NOT require the GPL license to be passed down to programs created using the IDE (I think). However, further down it reads, "the licensing depends only on the used libraries and software components and not on the underlying platform." Well, from what I can tell, some of Arduino is GPL V2, and the libraries are LGPL. So, if you use any Arduino functions, this indicates that you are using GPL licensed source code/functions in your source code, and that muddles the situation.

Anyone a license expert here? Or, does anyone have specific real-life examples of one way or another that you can cite?

The official Arduino libraries are LGPL. You can use the bootloader or libraries in support of your commercial product without restriction. You are not required to release your "sketch". Some unofficial libraries that you can find around the 'net may not be LGPL and you will need to abide by the terms of those libraries. In other words, the official Arduino developers are happy to see you using their work in your commercial product, but that does not necessarily extend to the work of all independent developers of Arduino libraries. If the licensing of a particular library is unclear then you need to contact the developer of that library for clarification. If that particular developer does not explicitly give you the rights to use his code then don't use it.

If you modify the LGPL bootloader or libraries and use them in a commercial product then you must release your changes to those libraries. In other words, if you're making useful changes to the same software that the Arduino project provided to you then you are required to release those changes. I hope you don't see that as a restriction though; really it's just being a good person and contributing back to the community.

Only the Arduino IDE is licensed under the GPL. You are not allowed to modify the IDE and sell it as a commercial product without also releasing the source code. I assume that's not what you're trying to do but you seemed unclear on what part of the Arduino project is covered by the GPL and not the LGPL.

this helps a lot, thank you. Also, to anyone else who may stumble upon this topic, here is a thread I recently discovered and found to be useful: http://forum.arduino.cc/index.php/topic,5451.0.html

LGPL really isn't all that great for an embedded chip; it's meant for run-time-linkable dynamic libraries. (You're supposed to provide a mechanism for the user to update the version of the LGPL library in use by the application, even if your part is proprietary. Which is practically ridiculous if you're talking about an AVR chip and Arduino libraries.)

But the stated INTENT of the Arduino folk to allow proprietary software trumps that, IMO, unless your company is deeply controlled by lawyers. Unless the Gnu people start suing people based on literal interpretations of their license, against the intents of the actual OSSW authors. (Which would be pretty suicidal, I hope.)

The AVR Libc license also applies...
http://www.nongnu.org/avr-libc/LICENSE.txt

This appears to be the most relevant clause...

Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

panther3001:
this helps a lot, thank you. Also, to anyone else who may stumble upon this topic, here is a thread I recently discovered and found to be useful: http://forum.arduino.cc/index.php/topic,5451.0.html

Hi,
Referring to the admin answer on link above, it is acceptable to use "Powered by Arduino" texing on your custom boards.
Is it acceptable to use logo and texting printed on the PCB?