Arduino GSM interface does not receive the SMS though it send SMS

Official Hardware Retired GSM Shield
1

Dear Friends,

I am trying to receive the SMS to A6 IoT GSM module, and try to read that sms over serial port. I am not able to receive the data over the serial port..

I am using this GSM module: https://www.aliexpress.com/item/mini-A6-GPRS-GSM-Kit-Wireless-Extension-Module-Board-Antenna-Tested-Worldwide-Store-for-SIM800L/32710017861.html

The code is as per below:

#include <SoftwareSerial.h>

#define GSM_RX 2 // Arduino pin 2 to UTX
#define GSM_TX 3 // Arduino pin 3 to URX

SoftwareSerial mySerial(GSM_RX, GSM_TX);

//char msg;
String msg;
void setup()
{
pinMode(4, OUTPUT);

Serial.begin(9600);
mySerial.begin(115200); // Setting the baud rate of GSM Module
delay(1000);
//mySerial.print("AT+CMGF=1r"); // set SMS mode to text
mySerial.print("AT+CMGF=1\r"); // set SMS mode to text
delay(200);
Serial.println("AT+CSMS=1\r");
delay(200);

mySerial.println("AT+CNMI=2,2,0,0,0"); // AT Command to receive a live SMS
//mySerial.print("AT+CNMI=2,2,0,0,0\r");

//mySerial.print("AT+CNMI=1,2,0,0,0\r"); // AT Command to receive a live SMS
delay(100);
Serial.println("Ready");
}

void loop()
{
if (mySerial.available()>0)
{
// digitalWrite(4, HIGH);
msg=mySerial.readString();
delay(20);
Serial.print(msg);
}
}

Please help on this..

Thanks
Rakesh Patel

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2

It seems arduino nano is not able to fetch the data from the GSM module.. if i connect GSM module with TTL to USB converter.. i received the perfect string.. But with arduino no luck.

3

try to reduce 115200 to 9600

4

I did but no luck.. and other thing is the module is communicate on 115200 baud rate.

5

hi,
the example codes seems to me too simple. I have no experience with SIM800 but only with SIM900. The library code for receiving SMS with a SIM900 is like in the attachment.

As you can see there is much more commanding and checking.

Are you sure that your code is sufficient?

SMSexample.txt (8.95 KB)

6

Its seems this is the library API.

I have installed the library. I wanted to test the Arduino code for SMS receiving application.