[SOLVED] SIM300 communication problem

[vishwassharma]

I am having problem with SIM300 module connection,

I am using NewSoftSerial library and the example given on **broken link removed** where I expect that after getting msg like

RDY

+CFUN: 1

+CPIN: READY

Call Ready

code is

#include <NewSoftSerial.h>
NewSoftSerial cell(4,5); // 4 is RX and 5 is TX
char incoming_char=0;
void setup()
{
//Initialize serial ports for communication.
Serial.begin(9600);
cell.begin(9600);
Serial.println("Starting SIM300 Communication...");
}
void loop()
{
//If a character comes in from the cellular module...
if(cell.available() >0)
{
incoming_char=cell.read(); //Get the character from the cellular serial port.
Serial.print(incoming_char); //Print the incoming character to the terminal.
}
//If a character is coming from the terminal to the Arduino...
if(Serial.available() >0)
{
incoming_char=Serial.read(); //Get the character coming from the terminal
cell.print(incoming_char); //Send the character to the cellular module.
}
}

but once I use terminal for communicating with computer, where i am sending AT commands to SIM300. I have been trying sending "AT" commands but i am not getting any response

I am working on Arduino Uno with 5 Volt connected to Diode IN4007 to step down voltage to range of 3.6 to 4.5 V. RX of sim300 is connected with TX of Arduino and viceversa. and Gnd of SIM300 connected with GND of arduino.

Please help me .. I am trying this for quite a long time.

 

[doec]

The AT command should be ended with "\r" character in order to get response from SIM300.
Regards,
doec

 

[vishwassharma]

The AT command should be ended with "\r" character in order to get response from SIM300.
Regards,
doec

if you mean that using terminal if i use +CR i will have some communication. I have tried this see the screenshop along here.


Nothing happens still .. .. still getting all the follow ups... In-fact one interesting thing happens. If i send AT command before Call Ready then I get a response OK.

If i sends AT continuously, I force SIM300 to restart (is that normal ??).

 

[vishwassharma]

There is a power issue with arduino. As I was connecting it with computer USB driver for power supply and USB do not have current in approx range of 20mA . For sim300 we need current greater than what USB can provide.

I am using LM317 variable power supply to power sim300 module with common ground to arduino.

If someone have a similar issue i would be happy to help.

Regards
Vishwas Sharma