a 3-pin plug having 110 V fixed power supply. It is possible for the power meter to restrict
electronic devices’ power usage through the use of circuit restriction techniques.
The role of the power meter is that of a router which can get dierent commands extends
the ZigBee network. These commands are used for: reading the device ID, getting the On/O
device status, reading device name, controlling the power switch, and reading the IEEE address.
To show the device status, the power meter has an LED light and a button. For implemen-
tation, the near ZigBee devices serve as a router or coordinator so the network can be joined by
other devices.
When the power meter is powered, it directly joins and enters the network while
setting up the state which can facilitate any other device in joining the network. For such
a scenario, the LED light is known to blink only once per second. If you want to reset the
power meter, cut its power by unplugging the power source and press the button and keep
holding it. When you hold the button, plug the meter again with the socket and then wait
for 3 seconds. Subsequently, stop holding the button as your power meter is restored to its
factory configurations.
Transceiver
The transceiver is connected to an embedded device or computer through a USB port. For this
USB interface, the FTDI FT232RC chip is used while the computer or the embedded device gets
the installation of FTDI VCP driver. The USB port can be used to send or receive any commands
to control the ZigBee transceiver.
ZigBee/Wi-Fi Configuration
The internet of things access point which has been proposed in the paper executes two wireless
protocols simultaneously. This includes WiFi (IEEE 802.11n) and ZigBee (IEEE 802.15.4).
AZigBee wireless protocol can be used to establish the ZigBee home network. In the smart
home environment, all the ZigBee devices are integrated seamlessly.
The ZigBee devices for handheld devices can be accessed by the Wi-Fi wireless protocol
via the internet. But the ZigBee is known to share a 2.4 GHz ISM band while working with
Wi-Fi and other radio transceivers. Hence, the combination of both Wi-Fi and ZigBee is a
crucial topic.
Each frequency band of 5 MHz is divided by the communication protocol of ZigBee and
converted into 16 channels having channel numbers from 11 to 26. For each channel, the fre-
quency is 2 MHz without the channels aected by a spectral overlap. On the other hand, the
frequency band is divided into 13 channels having numbers from 1 to 13 by the communication
protocol of Wi-Fi. Here, each channel has an area of coverage with 22 MHz. Hence, for channels
1, 6, and 11 there is no possibility of spectral overlap being overlapping. Since this causes issue
related to the reduced transmission speeds, therefore channels 1, 6, or 11 are utilized for setting
up the channel settings of the Wi-Fi network.
The IEEE 802.11n WLAN along with larger RF bandwidth is used by the ZigBee to share the
congested 2.4 GHz ISM band. In order to decrease the wireless signals’ interference, the paper
uses Wi-Fi having a higher opportunity to grab among the 1, 6, and 11 channels. In the same
way for ZigBee, the paper emphasized to select 15, 20, 25, and 26 as one of the channels that fits
the non-overlapping IEEE 802.11n criteria. Moreover, the internet of things access point which
has been proposed can generally use Wi-Fi and ZigBee without the need for signal interference
and the internet of things access point can be used to build the smart life application.
190 Internet of Things
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