USB toy
USB toys are toys or gadgets which draw their electrical power from the USB or Universal serial bus on a computer.They are also known as "office toys".
Power supply for USB toys
The USB specification provides a 5 V (volts) supply on a single wire from which connected USB devices may draw power. The specification provides for no more than 5.25 V and no less than 4.35 V between the +ve and -ve bus power lines.
The USB connector was originally designed as a replacement for the serial and parallel ports on computers. It was hoped that eventually a number of devices would be able to daisy chain together using the USB ports. The use of a USB port to power toys was probably not what they were intended for.
There are, broadly, 2 categories for USB toys.
Useful toys
These are gadgets which aim to fulfill a useful purpose but are of limited practicality due to the restrictions on the power supply through the USB port. A good example would be a paper shredder ( see picture). Other examples would include reading lamps.
Fun toys
These have no practical use other than pure fun. An good example would be a toy missile launcher.