Today GSM networks are
widely used, either for making calls or sending SMSes. Let us discuss a project
of controlling home appliances by sending sms.
There are many types of
home automation systems available in the market. Some are DTMF controlled home
appliances, IR remote controlled home appliances and RF based. This system
executes accurate control according to the message sent by the mobile phone.
Just by sending a message to the GSM modem interfaced to a Arduino
microcontroller (MCU) on/off operations can be performed. Present status of the
equipment is also verified through a LCD display.
Arduino Microcontroller
based home automation system works off 12v power supply. Arduino
microcontroller (MCU) requires only 5v but GSM modem requires 12V. A LCD
display is used for receiving and displaying the messages. Here LCD is used in
4-bit mode, which means only four lines are required to display data. When you
want to control equipment and show its status information, you need to send an
SMS to GSM Modem. Arduino Uno reads the messaged received by the GSM modem and
sends commands to control the equipments and displays its status on LCD. GSM
modem sends the commands in the text mode to Arduino Uno using RS232 interface.
AT command is sent from
Arduino Uno to the GSM modem as the program starts up, and the response is
received from the GSM modem after a very short period of time. After receiving
the command to turn on loads, the relay set performs the switching operation.
The home automation market
is growing very fast and there is a need a vast range of developments is
carried out. Arduino Uno along with GSM provides smart automated home system
with desired buad rate of 9600 bps.
