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Fast Check - Send SMS

1 ) Here is the product link Sim900 GSM Module

2 ) Here is the connection of Sim900 GSM Module . Take more attention on Transmit TX and receive RX pin .

3 ) Here is the connection between arduino and Sim900 gsm module .
Arduino RX --> Sim900 TX
Arduino TX --> Sim900 RX

Status LED ( fast blink ) --> SIM Card is not connected to network
Status LED ( heart beat blink ) --> SIM Card is connected to network

4 ) After done the wiring and insert sim card , download this code . In the code , change the phone number where the sms should be sent to .

5 ) Open the serial monitor and upload the code .

6 ) Make sure the baud rate is set to 9600 . If there is no problem , sms should be sent to your number set in the code .

7 ) SMS successfully sent .


  1. i have this problem that i couldnt find the solution
    i changed the baud valor alot émoticône cry

    1. i'm using the same code
      :'( :'(

    2. Seem like your SIM900 is responding well. This can be seen on line 3 and line 4 from below.. Arduino sent AT and SIM900 response OK

    3. Salam...saya guna code sebiji macam diatas dekat uno dia jadi tp bila saya pakai dekat mega dia tk jadi kenapa ya?

    4. Wiring setup and coding will be a bit different for Arduino Mega

  2. bagaimana cara cek pulsa lalu di tampilkan di LCD?


    1. You may get the status just from serial data.
      Off course you need to add more code there.

      Check our other sim900 tutorial which use LCD.

  3. Assalamualaikum Tuan. Boleh tuan tlg cek kenapa sy tak boleh sent sms?

    and one more thing, boleh sy tahu #include ni dr library mane ye tuan?

  4. hi can i know do this sim900a able to interface with AT89C51? also can i know which pin should i use the near from the antenna or the other one to connect wwith the microcontroller.

  5. Bole tak ltak wire drp gsm ke pin no 0 dan 1 di arduino uno?