This paper presents the design and implementation of a wireless sensor node for a Motion Capture system with Accelerometers (WiMoCA). It is composed by a tri-axial integrated accelerometer, a microcontroller and a wireless transceiver. WiMoCA nodes have been exploited to build a Wireless Body Area Sensor Network (WBASN) that allows to implement a wireless/wearable distributed gesture recognition system where nodes are mounted on many parts of the human body. We describe the hardware architecture and all the software layers supporting the recognition system. We also show characterization experiments on WiMoCA nodes that highlight how their performance and power consumption levels make them suitable to HCI applications.