Freeduino is an open-source microcontroller building platform that is based off of Ardunio® hardware. The distinction is not because the hardware is particularly different but because of the possibility of trademark infringement stemming from using Ardunio® hardware under the Freeduino name. The Freeduino system has no trademark, does not force users to ask for permission to make their own boards, and lets users make their own boards and sell them without any legal problems. All Duino systems are made to create microcontrollers, or circuit boards with all the hardware needed for a computer, that can have the programming warped and changed according to the user’s preference.
The Duino system, which is used to describe Freeduino, Ardunio®, and all derivative systems, is used to create a single-board microcontrollers. A single-board microcontroller is a small computer system made on one board. All the essential components of the computer are loaded onto the single board, making it very small and weaker than full systems but space efficient. These systems usually have command lines instead of graphic user interfaces (GUI).
Aside from saving space and being infinitely customizable hardware-wise, there is another advantage to using a Duino single-board microcontroller: controller customization. A controller or board can have new hardware added to it, but the hardware’s commands cannot be altered. A computer can access Duino systems, and the user can inject or change the existing code, meaning the user can change functions or lean the controller to prioritize other functions.
The original creator of this system was the Ardunio® company. When they made this system, they specified that it was open-source, but only under certain conditions and parameters. The lack of clarity about just how open-source the system was meant many creators were worried about making their own system.
To solve the open-source issue, Freeduino was created. This system is similar to Ardunio®, and is used colloquially to mean any system that is Ardunio® compatible, but does not use the official name. Unlike the open-source confusion, Freeduino is completely open-source. In terms of power, parts that can be used, and the software used to change the microcontroller functions, both Duino systems are practically the same.
People who create boards and hardware under this system are allowed to sell the product, configure it any way the programmer wants and change original designs. This can all be done without permission. This is why it is called "free duino" — because it is a Duino system without any restrictions on programmers.