Arduino Sim900 shield; receiving sms text in hex????

Using Arduino Networking, Protocols, and Devices
1

Hello.
I have a remote control project using the Nano and Sim900 shield.
Working fine when sending sms but when receiving sms something odd is happening:

This is the output from serial monitor:

[12:24:45:311] +CMT: "+47xxxxxxxx","","16/11/13,12:24:41+04"␍␊
[12:24:45:327] 000A00480076006F00720020007600610072006D00740020006500720020006400650074D83DDE00␍␊

Converting the hex string gives me the following:

(NUL)H(NUL)v(NUL)o(NUL)r(NUL) (NUL)v(NUL)a(NUL)r(NUL)m(NUL)t(NUL)e(NUL)r(NUL) (NUL)d(NUL)t(NUL)0=P(NUL)

The original message sent is (in norwegian);

Hvor varmt er det:-)

Init of Sim900 shileld is:

AT␍␍␊
[12:23:17:782] OK␍␊
[12:23:17:782] AT+CMGF=1␍␍␊
[12:23:17:782] OK␍␊
[12:23:17:799] AT+CNMI=2,2,0,0,0␍␍␊
[12:23:17:799] OK␍␊

Anybody have a clue??????

regards
Kjartan

2

Show us the line used to print the SMS to the serial monitor. It looks like your reading a character at a time and printing it (including the null terminator) as HEX.

3

Riva

These are the lines used sending it to monitor:

if(SIM900.available() >0)
{
incoming_char=SIM900.read(); //Get the character from the cellular serial port.
Serial.print(incoming_char); //Print the incoming character to the terminal.
}

I have also tried the most of other solutions amnong Serial.write(incoming_char);
and making even buffers ......

Regards

Kjartan

4

Hi Kjartan,

I'm having difficulty finding the SIM900 library your using so can you please post details of where the library came from and maybe post the code (or a working part of it) that shows the SMS receive problem.

5

Hi kjartani

It may be better to some of the control has been Form (controlpPanel), in real time. Web Form, Android or Windows?
I am interested in this topic, my projects are also associated with the remote control.

6

Hi Revi.
Im not using Sim900 library.
The commands sent to the Sim900 are the ATs.commands, and I use the SoftwareSerial for communication.
But I will explore the Sim900 library.....

Regards
Kjartan

7