Introduction ![enter image description here][1] This is a Bluetooth 4.0 module（Bluetooth 4.0 slave module）. Compared with Bluetooth version 2.0 and 3.0, it's more advanced for its lower power consumption. You can easily connect your own project to the primary device of Bluetooth 4.0 by using this module. For instance, it can transfer the detected data which is about the information of your body to phone for displaying or analyzing, then, help you better manage your physical condition. Specification Bluetooth 4.0 Module PIN:0000 Default Baudrate:38400 Dimensions: 25.43mm x 20.35mm Demonstration The demo is going to show you how to connect bluetooth device with Xadow BLE Slave and communicate. You can use it to communicate with phone(with Bluetooth 4.0). Now let us have a test: Connect the Xadow BLE Slave to Xadow Main Board and connect Main Board to PC with a USB cable. In normal mode, the blue LED will blink once a time. If the blue led is off, please click the "reset" button on Xadow Main Board . Note: when connect XadowBLE Slave to Xadow Main Board, you should concern about the connection direction. The connection method is that the unfilled corner of one Xadow module need to connect to the right angle of another module(see four corners of each Xadow module). Upload the test code to your Xadow Main Board. int error=0; int n; void setup() { Serial.begin(38400); delay(100); PORTB|=0x04; TESTIO(); if(error==0) { DDRB|=0x81; for(n=0;n