today I started to play with the A6 GSM board I purchased, after seeing it powers on I purchased a prepay SIM, one of Romanias operators has awesome prices (and an ok coverage in metropolitan areas), the price was the most important thing I chosed them as for 2Euro the prepay card has a 3 months active period , and 2Gb of internet trafic .. more than enough for sending sensor values, and alerts from time to time. All the other operators sell prepay SIM from 5 Euro / month ... it's a huge difference from 2 Euro / 3 months to 5 Euro / month. This was one of the reason that in the first place made me order an GSM module, as there was very cheap option to have that module always online .
I placed the SIM inside the module and started issueing some AT commands from my PC (just for testing, the module should be connected to an ESP8266 or an RaspberryPi) but imediately after powereing on the module I noticed some errors in the response of my commands, when I tried to call the SIM it was not connected to the network, when I issued the command :
AT+CPIN? +CPIN:READY OK AT+COPS=? +COPS: (3,"ROORANGE","ROORANGE","22610"),(3,"ROCOSMOTE","ROCOSMOTE","22603"),(3,"ROVodafone","ROVodafone","22601") OK
It sees the 3 main mobile providers but it doesn't sees the 4th, which I found out after googling a little bit, that is an 3G exclusive network, so only devices that support a 3G network will work with that SIM :(
And this is how all my hopes to add a GSM backup alerting system to my "Home Dashboard" project are gone. I wanted to use this module for important alerts (SMS in case of smoke detection, water leakage, internet connection drops, etc) as now the project I work on uses Pushbullet to send me notifications , on my mobile, but without an internet connection (if something happens), there's no notification :)
Are there other cheap modules that I ca buy and support a 3G SIM? I don't quite want to get an $50 GSM module for this, as I know it will take some time until I will finish this project, it will probably never be really finished as I always added new things .. but with so little time to play (in weekends) I don;t want to buy expensive devices, as anyway I purchased so many boards and they all are still in the original bag, in a big box labeled ARDUINO :D I'm fascinated by those small devices,you can do so many things with such a low investment ... if only those ware available when I was in collage :)
Wish you a happy sunday !