First we have to wire the SIM900A
with the Arduino that consists of two
parts the first part is the serial
communication that will communicate
between the Arduino and the SIM900 module the Serial communication
is consists of two wire that is Tx and
Rx. The Tx pin from the module we
connect to the Arduino pin 10 and the
Rx connected to the pin 11 and then we
insert the antenna to boost the signal
this will help if the signal is bad and
then the power cable. The power cable
consists of 5 volt and ground. Just
connect the 5 volt
to the 5v of Arduino and the ground to the
ground of the Arduino. If the wiring is
completed then we can plug the USB
cable but before we are doing that we have
to insert the SIM card to the SIM900
module this will help module to get the
signal. We can lock the SIM by pressing up
the SIM and then the SIM will locked and
now USB has connected
and we see LED blinking in the top-right
corner means that the module is
searching for a signal. If the blinking
is fast means the module get no signal and
if the LED blinking slower about once
every two seconds mean that the module
has got the signal
look closely at the blinking left in the
corner it's slowly now it's mean we are
ready to go. Okay it's time to open our
arduino ide we can copy the code from
the website link in the discription we
just copy the entire code to send and
receive message. This copy and open
our Arduino select all and then paste on
it now we have the complete sample code
and then we can upload  this code
but before we upload the code we check
first that the board is Arduino and the
com is the port is already in our com
just click upload and it should save the
file first we can name the file whatever
but in this symbol I will just type GSM
test for this example and now click Save
and the code is now compiling after the
compile it will upload to our Arduino
a little bit slow. Okay now it's done
uploading and then we can check the
serial monitor and to control the send
message open the serial monitor then it
should be appar "r" to send and I mean
"s" to send. r to receive the message
just type "r" and then enter and it's
now sending message to your number don't
forget to edit the number first from the
example because it is my number that
already in it okay now it's done and you
should receive the message from the GSM
and Arduino thanks for watching don't
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