TL;DR* Here's what the license entails:
1. Anyone can copy, modify and distribute this software.
2. You have to include the license and copyright notice with each and every distribution.
3. You can use this software privately.
4. You can use this software for commercial purposes.
5. If you dare build your business solely from this code, you risk open-sourcing the whole code base.
6. If you modify it, you have to indicate changes made to the code.
7. Any modifications of this code base MUST be distributed with the same license, GPLv3.
8. This software is provided without warranty.
9. The software author or license can not be held liable for any damages inflicted by the software.More information on about the LICENSE can be found here
Looking at the messages just now...
@pedro15 If your android app is for private (?!) use, you are not distributing. If you pu it in the Google Play store (for instance), you are distributing. One of tackling this situation is to force the user to install the plugin after the instalation. Then you are not distributing anything and what the user does is none of your concern.
@RogerInHawaii In your case, it is important to know what you are patenting. Is it the unique hardware part? Even if you open source your software, your patent would protect the hardware design. As for the software side, any unique addition that you offer with OSS GPV3.0 must be open source. Patenting that part is difficult and even if you do, enforcing or protecting it would be difficult.
Disclaimer: I am not a legal expert, get advice from an IP lawer.