BT-410 dongle converts two interfaces: USB 2.0 interface and Bluetooth 4.0 Low Energy interface (master function). That is, if you connect BT-410 dongle to the PC, it can be paired with BT-410 Slave module to exchange data (1:1 communication).
This is probably the smallest Arduino controller speically designed for controlling the servo. It features a 12 standard servo control capbility with Xbee socket which can be used to control helicopter or UAV via the Xbee link. The feather weight (7.5g) make it an ideal controller for those application that has limited payload. The build in regulator is allow the input voltage vary from 3.5-8V which fits the most power supply without any modification.
In many robotic applications it is a requirement to provide continuous power supply without having to reset the system when changing batteries or when switching between DC power supply and battery source. RoboSavvy HotSwap Power Board 1.0 is designed to provide continuous power to a robot allowing the interchangeable use of two DC power sources