A universal serial bus (USB) Arduino® is any Arduino® board that uses a USB as its primary interface. Arduino® is an open source microcontroller and electronics platform. Practically every desktop and laptop computer comes with USB ports, meaning that USB devices can interface with almost any computer. There are several varieties of these boards in production.
The purpose of the USB Arduino® interface is to allow the computer to reprogram or provide instructions to the device. For example, a programmer using a board outfitted with a short range radio might wirelessly connect to a system that controls the lights in his or her house. Once connected, the programmer could tell the program to change lighting modes and set all lights to levels appropriate for a dinner party if the program includes a dinner party mode. If the program does not include a dinner party mode, he or she could use the same interface to upload a modified version of the program to the device.
Most Arduino® devices do not use separate computer interfaces for input and programming. If a computer interfaces with an invention over a USB connection, it is unlikely to have any other mechanism for doing so. These devices can accept input from other sources, such as sensors and switches. A device being used to control lighting could also accept instructions from a dial on the wall or from a light or motion sensor. Sensors and switches, while technically interfaces, are far more limited than a USB or other computer interface and cannot be used to reprogram a device.
There are several advantages to using a USB Arduino® over other interfaces for the microcontroller. Besides being common, the USB interface is also cheap and fast. It requires very little power to operate, and the USB connection can be used to charge the device while connected. USB cables are also much simpler to wire and repair than wireless data transmission methods or older serial cables.
The main limitation of the USB Arduino® is that it must be physically connected to the computer to interface with it, so to eliminate this limitation, several wireless computer interfaces have been created for the platform. Wifi® boards can easily interface with computers as long as there is a wireless router present. Xbee® boards operate more independently and over longer distances. Bluetooth® boards still have limited range, but have the additional advantage of being able to interface with smartphones. Despite some limitations, USB Arduino® boards are cheaper and more power efficient than wireless alternatives.