Havn't fixed it yet. Even by using the usb to serial 232 cable and a MX232N chip and using a voltage divider to decrease the input RX port of the SIM900 module its not responding to any of my AT commands. There's some additional underlying problem than it jsut being brought down to 2.8V. Unless I burnt the module already. But its doing the same thing as it did when I first bought it so its something im not doing right.

I made a PCB to mount the nRF24L01, but for some reason the prototyping machine connected my MISO and MOSI routes and burnt my module. Now I have to go with XBEE due to time constraints.

Its LED blinks close to every three seconds, but Im sure its the "Not Registered" timing.

I couldn't get a hold of an ITead Studio representative to find out if its unlocked, but when I called Rogers Wireless they said that if the SIM900 module isn't manufactured for a specific carrier it shouldn't be lock. And I assume they would provide me with an unlock code if it was locked.

The antenna should be fine, it was the one supplied by ITead studio. I even tried connecting with an external SMB connector and a cable to bring the antenna further away from the module in case of any interference with the SIM900 module as Boris Landoni recommended in another forum.

I am using a 9V 1.5 A power adapter so it should be giving me about 13.5 Watts. It should be enough power.

I tried connecting to the module via  MAX232N serial to Serial 232 connection. I have the MAX232N IC in this connection:

http://sodoityourself.com/max232-serial-level-converter/

and I had a serial 232 to usb cable on the other end. I was able to receive message from the SIM900 module, but any AT commands I sent the other way seemed to have no effect.

I was wondering if I need a new SIM card with a new account to register the unique IMEI number but Rogers Wireless said that it should automatically register my module on their network.

I tried adding data to my plan in case that would work, but it did nothing. Tried multiple Arduino boards and now I now of another person with the same problem using the same Module. Theres a new GSM library version, I think Im going to try that next.

Either that or try ordering a seeed studio module instead.

Ecave

So if I'm using the Debug port I need to use a voltage divider on the RX Port of the gsm module?

I can receive messages in Hyperterminal but I get no response to the commands I send.

The Shield should already step down the voltages right?

LOL  Those questions should have been answered in the original post. The LED's are working and the GSM module does power on.

Once connnected the PWR light is on.

One the power button is pushed:
- The NET light is solid green for a second

Then it goes to a communications state:
      -Status light is solid green
      - Net light is 64ms On/300ms Off  (GPRS communication is established)

Then after registration failure (or at least I assume is the problem):
     - Status light si still solid green
     - the Net light flashes 64ms On/800ms Off (SIM900 not registered the network)

I called Rogers my service provider adn they said as long as the SIM900 Module is unlocked it should register automatically.

In the serial window I still get:

system startup
GSM doesn't response
Registration 0
GSM doesn't response
Registration 0     (Repeats this way)

I connected through the Debug Port last night using a MAX232 chip and a USB to RS232 cable and I get the same response in Hyperterminal:

system startup
GSM doesn't response
Registration 0
Registration 0
GSM doesn't response
Registration 0     (Repeats this way)

I've tried the commands in hyperterminal but I get no response from the module.

AT+CPIN?
AT+GSN
AT+CSQ
AT+CREG?
AT+COPS?
AT+GMR

If I can receive data from the GSM module then I know I have the TX and RX port connected correctly for the debug communication throught the Debug port. But the maybe I dont have the right Hyperterminal setting.

Thanks for you response,

ecave

Hello all,

Did anyone have this problem:

GSM no response
Registration 0

Is there something else you have to do to get it to work?

Ecave

Hello all,

I am using the GSM Module from Itead studio. I cannot get it to register on the GSm network,

This is the module:

http://iteadstudio.com/produce/sim900-gprs-shield-icomsat-preview/

The response I get in the serial window is:

system startup
GSM doesn't response
Registration 0

and in the arduino software:

Error inside Serial.serialEvent()
java.io.IOException: Bad file descriptor in nativeavailable
   at gnu.io.RXTXPort.nativeavailable(Native Method)
   at gnu.io.RXTXPort$SerialInputStream.available(RXTXPort.java:1532)
   at processing.app.Serial.serialEvent(Serial.java:215)
   at gnu.io.RXTXPort.sendEvent(RXTXPort.java:732)
   at gnu.io.RXTXPort.eventLoop(Native Method)
   at gnu.io.RXTXPort$MonitorThread.run(RXTXPort.java:1575)


it seems that its not able to register on the gsm network.

Any help would be great. I am giving up and consider the SIM900 package on the module to be broken and i dont think its worth buying another.

Thanks Paulware, I used the nRF24L01 modules and they work perfectly and they're all in a nice package. Now I just have to modify for the code to switch from send to receive based on an input.

You should write a port on using Iteads GSM Module. Its giving me a headache:

http://iteadstudio.com/produce/sim900-gprs-shield-icomsat-preview/

Hello all,

I am in the process of creating a custom wireless system that has base station PCB with an embedded ATMega328 and a transceiver module as a section of the PCB. This base station then sends and receives signals from a portable wrist module.

My question is: What is the most minimal (cost and weight) design for a handheld wrist module that can both send and receiver a signal from the base station? (I am trying to keep the wrist module as small as possible to fit into a custom polystyrene enclosure when I'm done.)

My completed wrist module will have a transceiver, an antenna, a voltage regulator, power source, output LED and Speaker, but I will also have a input digital signal from a toggle switch. I'm in the process of creating a PCB for the wrist module, but I'm starting to think I'll need an ID component for the wireless communication so that the the base station and wrist module don't pickup and process interfering signals on the same frequency band. Will I need a microcontroller on the wrist module PCB to encapsulate my data or will an text filter ID if else statement in the wireless communication code work?

I'll attach my code and sample PCB for any interested/experienced enthusiasts.

Thanks,

ecave

Wireless wrist module summary:
- one input(toggle switch) and two outputs(LED and speaker controller via 555 timer)
- one transceiver
- power source

Is a microcontroller necessary to control circuit