The LilyPad Arduino USB is the perfect board for e-textiles and wearables projects. It can be sewn to fabric and to power supplies, sensors and actuators with conductive thread. You can attach this board directly to your computer using only a micro USB cable.
The LilyPad Arduino USB is a microcontroller board based on the ATmega32u4. It has 9 digital input/output pins (of which 4 can be used as PWM outputs and 4 as analog inputs), an 8 MHz resonator, a micro USB connection, a JST connector for a 3.7V LiPo battery, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a battery to get started.
The LilyPad Arduino USB differs from previous LilyPad boards in that the ATmega32u4 has built-in USB communication, eliminating the need for a separate USB-to-serial adapter. This allows the LilyPad Arduino USB to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port. It also has other implications for the behavior of the board; these are detailed on the Getting Started page.