zigbee
module
XBee and XBee-PRO Modules were engineered to meet
ZigBee/IEEE 802.15.4 standards and support the unique needs of low-cost,
low-power wireless sensor networks. The modules require minimal power and
provide reliable delivery of critical data between devices. The modules operate
within the ISM 2.4 GHz frequency band and are pin-for-pin compatible with each
other.The XBee and XBee-PRO OEM RF Modules
were engineered to meet IEEE 802.15.4 standards and support the unique needs of
low-cost, low-power wireless sensor networks. The modules require minimal power
and provide reliable delivery of data between devices. The modules operate within the ISM 2.4 GHz frequency and are pin-for-pin
compatible with each other. ZIGBEE is an open technology developed by the
ZIGBEE Alliance to overcome the limitations of BLUETOOTH and Wi-Fi. ZIGBEE is
an IEEE 802.15.4 standard for data communications with business and consumer
devices. It is designed around low-power consumption allowing batteries to
essentially last forever. BLUETOOTH as we know was developed to replace wires
and Wi-Fi to achieve higher data transfer rate, as such till now nothing has
been developed for sensor networking and control machines which require longer
battery life and continuous working without human intervention. ZIGBEE devices
allow batteries to last up to years using primary cells (low cost) without any
chargers (low cost and easy installation). The ZIGBEE standard provides
network, security, and application support services operating on top of the
IEEE 802.15.4 Medium Access Control (MAC) and Physical Layer (PHY) wireless
standard. It employs a suite of technologies to enable scalable,
self-organizing, self-healing networks that can manage various data traffic
patterns. Thenetwork layer supports various topologies such star clustered tree
topology and self-healing mesh topologywhich is essential in Smart dust apart
from easy installation and easy implementation ZIGBEE has a wide application
area such as home networking, industrial networking, Smart dust, many more,
having different profiles specified for each field. The upcoming of ZIGBEE will
revolutionize the home networking and rest of the wireless world.
Key
Features:
LongRange Data Integrity:
XBee
Range
Ø Indoor/Urban:
up to 100’ (30 m)
Ø Outdoor
line-of-sight: up to 300’ (100 m)
Ø Transmit
Power: 1 mW (0 dBm)
XBee-PRO Range
Ø Indoor/Urban:
up to 300’ (100 m)
Ø Outdoor
line-of-sight: up to 1 mile (1500 m)
Ø Transmit
Power: 100 mW (20 dBm) EIRP
Ø Receiver
Sensitivity: -100 dBm
Ø RF
Data Rate: 250,000
Advanced Networking & Security
Ø Retries
and Acknowledgements
Ø DSSS
(Direct Sequence Spread Spectrum)
Ø Each
direct sequence channels has over 65,000 unique network addresses available
Ø Point-to-point,
point-to-multipoint and peer-to-peer topologies supported
Ø 128-bit
Encryption.
SPECIFICATIONS:
PIN SIGNALS:
Electrical Characteristics:
4.13.6 FLOW CONTROL:
DI (Data In)
Buffer:
When serial data enters the RF module through the DI
pin (pin 3), the data is stored in the DI Buffer until it can be processed.
Hardware Flow Control (CTS):
When the DI buffer is 17 bytes away from being full;
by default, the module de-asserts CTS (high) to signal to the host device to
stop sending data [refer to D7 (DIO7 Configuration) parameter]. CTS is
re-asserted after the DI Buffer has 34 bytes of memory available.
How
to eliminate the need for flow control:
1.
Send messages that are smaller than the
DI buffer size.
2. Interface at a lower baud rate [BD (Interface
Data Rate) parameter] than the throughput data rate.
Case
in which the DI Buffer may become full and possiblyoverflow:
If
the module is receiving a continuous stream of RF data, any serial data that
arrives on the DI pin is placed in the DI Buffer. The data in the DI buffer
will be transmitted over-the-air when the module is no longer receiving RF data
in the network.
DO (Data Out) Buffer:
When
RF data is received, the data enters the DO buffer and is sent out the serial
port to a host device. Once the DO Buffer reaches capacity, any additional
incoming RF data is lost.
Hardware
Flow Control (RTS):
If
RTS is enabled for flow control (D6 (DIO6 Configuration) Parameter = 1), data
will not be sent out the DO Buffer as long as RTS (pin 16) is de-asserted.
Two
cases in which the DO Buffer may become full and possibly overflow:
1.
If the RF data rate is set higher than the interface data rate of the module,
the module will receive data from the transmitting module faster than it can
send the data to the host.
2.
If the host does not allow the module to transmit data out from the DO buffer
because of being held off by hardware or software flow control.
4.14 GSM SIM
900A:
If you are in Europe or Asia and
using a mobile phone, then most probably you are using GSM technology in your
mobile phone.
GSMstands for Global System for Mobile Communication. It is a digital
cellular technology used for transmitting mobile voice and data services.
The concept of GSM emerged from a cell-based mobile radio
system at Bell Laboratories in the early 1970s.
·
GSM is the name of a
standardization group established in 1982 to create a common European mobile
telephone standard.
·
GSM is the most widely
accepted standard in telecommunications and it is implemented globally.
·
GSM is a
circuit-switched system that divides each 200 kHz channel into eight 25 kHz
time-slots. GSM operates on the mobile communication bands 900 MHz and 1800 MHz
in most parts of the world. In the US, GSM operates in the bands 850 MHz and
1900 MHz.
·
GSM owns a market
share of more than 70 percent of the world's digital cellular subscribers.
·
GSM makes use of narrowband
Time Division Multiple Access (TDMA) technique for transmitting signals.
·
GSM was developed
using digital technology. It has an ability to carry 64 kbps to 120 Mbps of
data rates.
·
Presently GSM supports
more than one billion mobile subscribers in more than 210 countries throughout
the world.
·
GSM provides basic to
advanced voice and data services including roaming service. Roaming is the
ability to use your GSM phone number in another GSM network.
·
GSM digitizes and
compresses data, then sends it down through a channel with two other streams of
user data, each in its own timeslot.
FEATURES OF GSM MODULE
·
Improved spectrum efficiency
·
International roaming
·
Compatibility with integrated services digital network (ISDN)
·
Support for new services.
·
SIM phonebook management
·
Fixed dialing number (FDN)
·
Real time clock with alarm management
·
High-quality speech
·
Uses encryption to make phone calls more secure
·
Short message service (SMS)
·
The security strategies standardized for the GSM system make it
the most secure telecommunications standard currently accessible. Although the
confidentiality of a call and secrecy of the GSM subscriber is just ensured on
the radio channel, this is a major step in achieving end-to- end security.
Radio modem by SIMComm is used in the
shield. Communication with the shield can be done easily with the shield by
using AT commands. It Supports features like Data, Voice, GPRS, SMS and
integratedTCP/IP stack. The connections of GSM module are done directly to PC
through serial port/to microcontroller through serial interface with the use of
MAX232. In addition to this, In GPRS mode, it can be connected to internet to
run various applications for recording data over the time and to any remote FTP
server to upload files for the data to be saved. For different applications
particular specifications are required which are mentioned in datasheet of GSM modules
GSM Module
In
this system, SMS application is used which is intended for the person who is
monitoring the value of CO in a room or an industry whenever it exceeds a
particular safe limit chosen according to a particular application. The
threshold safe limit as well as the mobile number of the person to which the
text message is to be sent is programmed in the Arduino which can be changed
for any specific purpose.
