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Topic: No RX data returned after sending AT commands (Read 1 time) previous topic - next topic

encryptor

Feb 08, 2015, 02:49 am Last Edit: Feb 08, 2015, 02:50 am by encryptor
Here is my video of the problem.  I have the TestModem sketch uploaded on the Arduino Uno.  Also I accidentally call the mic an antenna.

youtube arduino gsm problem

encryptor

Here's my 2nd attempt where I connect the bluetooth antenna directly to the GSM module.  I'm receiving data back from the modem, but it's unreadable to me.  Please look at my 2nd youtube video.  Thanks.

GSM Module with SIM900A - Attempt 2

dannable

I can't access youTube from work and at home I'm on a mobile connection and video eats up too much of my bandwidth.
Beginners guide to using the Seeedstudio SIM900 GPRS/GSM Shield

encryptor

I believe I know why my data is coming thru all cryptic.  I think it's because my circuit is missing a FT232 chip, which allows for UART to USB conversion.  I thought using the Arduino Pro would get me around that issue, but I don't believe it does.

hugo007

Dude your video does not give us any help, just some clues from what it could be tricking you.
You have your modem connected to the arduino and arduino connect to the bluetooth.Unless your arduino is parsing what he received via the software serial object created for bluetooth to your native serial port, it will not send any byte  to your modem.
My advise for now is to remove your arduino from the game and just try to connect your modem directly to your bluetooth. This way you can send commands to your modem using your computer to make be sure for things like  the baud rate and to  be sure you are talking to him successfully.Then inserted the arduino on the middle when you complete this task
Debian,Mint,Ubuntu
Arduino Mega 2560
Arduino Nano
Arduino Duemilanove
MAC OS Montain Lion
Raspberry PI Model B

encryptor

I attempted what you said, but the RX data received from the modem is all cryptic.  Changing the baudrate didn't help.  I think I'm missing the FT232 chipset that gives me UART to USB bridge.  Please see my other post with a link to my 2nd attempt.

leitronik

Hi. Im having the same troubles. Im using the Qualcom Shield with sim900.
At first i was using the gsm library wich you can find in the arduino IDE but i find out that when you make a call you cant hang up until the receptor picks it up.  The library has an endless loop until the receptor answers, hangs, or it reachs the timeout. So im starting to use the AT commands to make the voicecalls.
In the examples i've found they didn't initialize the sim with the pin code and i cant make it work!!!!
The at commands i'm sending aren't working at all, i recieve no reponse.
i have try
Serial.println("AT");
Serial.write("AT");
i have also tried to create a softwareserial port in the pins (2,3)
gsm Softwareserial(2,3);
and then
gsm.write("AT");
gsm.println("AT");

I would love any kind of help to make the silpliest voice call with at commands on a sim with pin code.
┬┐Can I initialize the sim with the gsm library and then use "ATD+34123456789" with an "ATH" to hang ?
Im lost in the darknes.
Help...

dannable

The libraries provided with the IDE are for use with the official Arduino GSM/GPRS shield and may contain AT instructions specific to the Quectel M10.

Can you provide a link to the shield you are using?
Beginners guide to using the Seeedstudio SIM900 GPRS/GSM Shield

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