I have a SeeedStudio GSM shield (version 1.0) on an Arduino Uno with an AT&T GoPhone Sim Card. I set it up according to the SeeedStudio wiki, and successfully sent a text to my phone. Now I can only receive texts on the shield/Uno and the text is only three characters long. If I text the word "Test" it only reads "Tes." The green light flashes once every three seconds and when I power the board up it reads:
RDY
Is there an issue with this gsm shield and the SIM card? Or did I screw up some of the shields settings? I tried to figure this out without posting, but my head is spinning after a week of running around in circles. Eventually I want to connect a PIR sensor to the board and receive a text to my phone when it detects movement. Any help would be greatly appreciated. Yes, I am new to this gsm process. Thanks.
Chadro:
I have a SeeedStudio GSM shield (version 1.0) on an Arduino Uno with an AT&T GoPhone Sim Card. I set it up according to the SeeedStudio wiki, and successfully sent a text to my phone. Now I can only receive texts on the shield/Uno and the text is only three characters long. If I text the word "Test" it only reads "Tes." The green light flashes once every three seconds and when I power the board up it reads:
RDY
Is there an issue with this gsm shield and the SIM card? Or did I screw up some of the shields settings? I tried to figure this out without posting, but my head is spinning after a week of running around in circles. Eventually I want to connect a PIR sensor to the board and receive a text to my phone when it detects movement. Any help would be greatly appreciated. Yes, I am new to this gsm process. Thanks.
How is powered your arduino ? This shield really needs an external power supply, especially during active communications .
What serial speed do you use ? try with a lower speed .
Initially, I used the USB for power and I successfully sent a text from the board once @ 19200 (per wiki). I will use the A/C power plug, change the speed, and try again. Any suggestion on speed? Thanks.
Do you use softwareserial, or the hardware serial port ?
I had some issues too with this shield and softwareserial, it worked better at 9600 and even better at 4800 , but my project involves several external devices, and speed was not the only cause of malfunction : the shield seems to be very sensitive to +5V fluctuations and I had to deal with that too .
I need to investigate to see if it works now because of the speed @4800 or the fact that I fixed the 5V problems.
my advice : first try to use an external power supply , if it doesn't work, try 9600 bauds then 4800
there is an AT command that allows you to change and register a new speed, but I never tried it (if you don't use it, it is set to "autobaud" mode, which has some limitations), I want to be sure of the speed before . But using it might solve the problem
as you can see, I've got it to work, but cannot tell what actually did the trick, I'll find out soon
It's working now! I used the a/c power, switched the speed to 9600, and was able to send and receive texts. I'm going to go back and find out what exactly corrected the problem (power, speed?). I'll post when I figure it out.Anyone have a link or information for some gsm code? Like the op, I just want a PIR sensor to send me a text message when the sensor detects movement. Thanks for the help
