Problem with GPRS shield (no communication at all)

Products & Technology Shields
#21

Hi all,
I have/had the same problem with my GPRS shield (no answer on Rx).

  • Using GPRS Shield with Stalker v2
  • OK_READ Jumper on my Stalker is dismounted
  • Both Jumpers are on “SWSerial” mode
  • I haven’t done any firmware updates
  • Red status LED on, Net flashing every 3 secs
  • NewSoftSerial v10c

My workaround in detail:

  • Modify the Code from seeedstudio.com/wiki/GPRS_Shield#Support (section “Usage”-Step1 - 7.)
    -> Paste following into the loop section “mySerial.print(“AT”);”
    -> Upload this code into your arduino
  • If I connect via terminal (19200 8-N-1), I can see the GPRS Shield answers (wait a few seconds)
  • Then modify the code back by deleting the line “mySer…” and upload the code again
  • Make sure you don’t turn the gprs shield or the arduino off during the whole process
  • Voila, if I then connect again via Terminal the GPRS Shield answers on all AT commands
    BUT:
  • If I turn the GPRS Shield (or the Arduino) off and on again and connect via terminal afterwards, I don’t get any answer from the GPRS Shield again

Maybe someone from the seeed team has an idea why the GPRS shield is behaving like this?!

Thanks

#22

I believe that tannek is right and there are some bad soldering with Q3 and Q5 (maybe bad lot?), so I tried to resolder Q3 and Q5. They are very small and it seems that I killed them with heat. Power led is working status and net light blinking at start, but still no response via terminal. Any ideas how I can test that I soldered Q3 and Q5 right or not right?

What are the numbers of Q3 and Q5 so I can change them with new?

Thank you,
Nick

#23

I had the same problem with the softserial RX not responding.

in the end the fix was quite easy: increase the buffer size for newSoftSerial.

in NewSoftSerial.h on line 38 a constant for the RX buffer is defined:

#define _NewSS_MAX_RX_BUFF 256 // RX buffer size

default size is 64. this is not enough. I increased it to 256 and it worked.

cheers

#24

I have an iComSat v1.0 Arduino shield from iteadstudio and I still can’t get it working properly.

SIM900 GSM/GPRS shield for Arduino - IComSat v1.0
IComsat is a GSM/GPRS shield for Arduino and based on the SIM900 Quad-band GSM/GPRS module. It is controlled via AT commands (GSM 07.07)

I bought the shield from:

iteadstudio.com/store/index.php? … cts_id=413

These are the problems that myself and many other people are experiencing:

arduino.cc/forum/index.php/topic … #msg609237

I keep getting a problem:

system startup
no response

SMS ERROR
etc, etc

#25

i have downloaded the SoftwareSerial i have added to folder “arduino-0022\libraries\NewSoftSerial” and i have restared the ide.

And i get this error
error: ‘NewSoftSerial’ does not name a type
for this line
NewSoftSerial mySerial(7, 8);

I have also tryied to use it with the new Arduino 1.0 ide and i get an error when i include the SoftwareSerial.h
in line
#include <SoftwareSerial.h>
error
C:\Projects\arduino\arduino-1.0\libraries\NewSoftSerial/NewSoftSerial.h:71: error: conflicting return type specified for ‘virtual void NewSoftSerial::write(uint8_t)’
C:\Projects\arduino\arduino-1.0\hardware\arduino\cores\arduino/Print.h:48: error: overriding ‘virtual size_t Print::write(uint8_t)’

Any help?

#26

I just closed everything, restarted my pc and it compiled.

#27

Hello everyone;

I got the GPRS Shield some days ago, and I’ve just tried everything to communicate with it through serial. I do not have Arduino but I also bought the UartSbee V4,

  1. I wired my Uartsbee pin RX with GPRS pin 7 (D7)RX, then UartSbee TX pin with GPRS pin 8 (D8)TX, my GPRS shield jumpers was as SWserial mode.
    then I fired up my terminal and my GPRS shield with 5 volts power supply and wait until Netlight started blink each 3 seconds and the status led was in red. In the terminal session I started with 19200-N-1 and I typed AT, without response, then I switch to 9600-N-1 and all the bauds available obviously with Carriage Return.

  2. I tried to update the firmware of the Sim900 as jimbo.we suggested with simcom tool and I got exactly the same issues as guans screen shoots.

  3. I could not in SWserial mode so I set the jumpers in Xduino mode and I wire my UartsBee pin RX with GPRS pin 0 (D0)TX, then UartSbee TX pin with GPRS pin 1 (D1)RX, I tried all baud rates XXXXX-N-1 carriage return, and again no response from my GPRS Shield.

4.Finally I reset the SIM 900 chip directly with low pulse (ground) in pin number 16, I was sure that now everything going to be fine but the GPRS behaivor was exactly the same

I spent about 9 hours trying everything to figure my issues out without success, I’m really upset and I do not know what were wrong I think my GPRS Shield is damage, or Do I miss something?

My other question I ’ m not sure is my SIM is unlocked, but anyway according to me, the GPRS should reply either if it does not have a SIM attached, I mean it wont send SMS message but at least the shield has to reply an AT command with OK.

please guys I’ll appreciate any advice, please I need your help I 'm feeling really frustrated.

thanks & best regards

#28

Hello,

I have the same issue as you. I am going to try to increase the serial buffer from 64 to 256
as one of the previous posts stated. Did you try that yet?

#29

Okay this is my 2nd GRPS shield(previous one was off ebay)
If the lights are full red , greeen flash 3s then it’s not your SIM issue.
From what I see here it’s probably some communication settings or harware issue
I set buffer for software serial 256 nothing
I can’t even update firmware…
Any updates, anyone?