Arduino shield board
From Figure 2-1, the Arduino shield board has two power provision ways; one is RS232 interface. As show in Figure 2-1, by using the cable USB to RS232, wifi signal can be changed into USB signal to computer by RS232 interface. So, when the wifi module are inserted into the Arduino shield, the power is provided by USB cable. But, since the Arduino and the shield board are powered by USB from computer, it may be not enough for the power source. Therefore, the best way to provide voltage is the use of power adapter. This can promise the enough power. In addition, by utilizing such Arduino shield, the communication ways can be wifi and Bluetooth (ble) for the short wireless communication.