Thursday 4 January 2018

Project with SIM800L GPRS Module and Arduino: Part 01 AT Commands

I hope this is a
video that you are waiting for the most famous SIM 800 GSM module with arduino.
Using this, you can control any device and gent information from sensors to you
mobile phone wherever you be

If you are an arduino lover, you may be interested to work with mobile phone connections. I have seen some project which are activate with SMS or voice commands. but most of project are used old mobile phones. 

It is not easy to customize as our requirements. Therefore we can use GPRS module to make our own project as our wish. Most simplified and easiest way for a programmer is arduino platform. that is why i have used this SIM module with arduino. It  is not complicated. But there are more GPRS modules but I am using SIM800L module for this project.

Watch for more Details

Lets see the wiring as the wiring part is the most important part. It may be a cause to burn the device since a single mistake.

It should be connected arduino with sim800L module according to the above and connection will be shown as follows.

For more safety of the sim 800L module give the power to SIM800L module through Arduino Uno board through a diode as follows

Fore more details read the following image as well

If all the wiring connections are checked and confirmed as correct, go to arduino programme and do the coding. 

before the coding you must identify the correct direction of the sim card. it is normally printed on the surface of the sim slot.

To start coding, RUN arduino software.


Once the coding is uploaded, go to TOOLS > SERIAL MONITOR then, change the settings as follows

Now it is ready to check "AT" Commands.

Before check AT commands we have to check this module is working. Therefore you can take a phone call dialing the number of the sim using another sim. If you can hear the dialing tone, then your module is ready to work.

Now, Type AT in serial monitor and press ENTER, then serial monitor should display as OK. Then you can check with thousands of AT commands and learn how to work with sim800L module.

Click on following to download AT command list

Click on following to download the arduino  file

Arduino Code

SoftwareSerial Sim800l(10,11);
void setup() {
// put your setup code here, to run once:

void loop() {




If you have any clarifications, comments about this project 

please feel free to put a comment below.

Previous Post
Next Post

post written by:


  1. Hi, what supply did you use for the sim800l? Did you use an external supply for the gsm?

    1. No, I used +5v from arduino uno board through a diode. when the arduino board is is connected to Laptop computer.

  2. sir mine doesnt show anything. after I typed AT it doesnt show anything i followed everything correctly but still it doesnt work, does rx should blink?

  3. hello sir GSM sim800l does not connect to network,means only blink n/w LED/1s ,so how can connect sim800l to n/w.

  4. Hello dear,
    I upload this code as it is. But serial monitor does not work. Would you please help me?

    1. check your module with a phone call. if you can not hear dial tone, the module is not working

  5. Yes bro, I got response from SIM800L module. And my serial monitor also working.

    Now I want to drive 4 relay by sending SMS and also by calling and pressing button (DTMF).

    Would you please help me?

  6. can this work for arduino mega ?

  7. also my sim800 responds to call (ring moves to 0) but does not ear AT commands. I connected with a 3.3V serial so it should be ok. Any ideas?

  8. Hello My Name is Peter
    I have a Problem with de SIM800l Board. AT commands funktion with the Serial Monitor. But i Can`t send any SMS..
    I search many days an i don`t find the problem.
    Dit you have Time to HELP me?
    Special things:
    +CREG: 0,0

    Thanks for Help.

    Best Regards Peter

  9. Connection is according to sketch, GSM led blinking, called sim card number while on module and dial tone rang on cell but AT commands not working on Serial monitor please assist, I've ran out of options

  10. Hi, what do 3 red blinks from the SIM800L module mean?

  11. Hello. I'm trying to make a project with my Arduino and a SIM800L module (The red one with the spring like antenna). I activated my SIM card, tried it in my smartphone (and it's working) and i made the connections like you told to do. The problem is that i cannot call the SIM card once i put him in the SIM800l. I'm supplying the module with a 4.5V/3A power supply but the red LED blinks 3 times and then stops for 30 seconds and blinks again 3 times. Any ideas of what can be the problem?
    Thank you!

    1. Even i have the same problem ...any solutions ?

    2. the module needs 3.4V to 4.4V at 2A, you're killing the poor module ;-;

    3. Connect 1000 microfarad Capacitor between GND & Vcc Pins of the Sim800 module. Now the Network Led on sim module will blink after every 3 seconds. Can test connectivity with the network by calling the sim800 module from other phone. In response you will hear tone.

  12. Hello. there was such a question, as soon as I connect the sim800l to the arduino, the red light on the sim800l starts to blink 8 times, then it turns off and lights up again and so on all the time. Tell me what to do in this case?

  13. when i write AT in serial in show me AT in do not show ok. why?

  14. Does this work with Arduino nano

  15. Do not direct 5v of arduino to vcc of sim800.