MG2639 GSM Shield Connection (Mega2560)


I've been having problems getting a reliable connection (and intelligible feedback on serial) from a GSM shield - the MG2639 - I'm using for a project. I just need SMS capability.

How can I get a more reliable connection rate?

Connection is rarely established (say 1 in 5 times), but I can confirm it works - the Arduino can send an SMS when the temperature increases above a set limit. I'm aiming for an autoresponder-style setup in my project eventually, which I can leave alone for it to control a fan.

There's enough power (9V, 1,7A) and a 2G-compatible SIM, so those aren't the issues. I've also configured the shield to be usable with the mega and SoftwareSerial like so for use on pin 10. This set-up does work, but rarely.

Is it the pin I chose? Would there be a better one to try? Should I build a repeat loop into the .cpp file?

It doesn't matter which example sketches I'm using, this rarely gets off the ground. Any advice would be appreciated.



So I went away, had a more thorough look through the software serial known bugs, and broke the shield TX jumper out to a breadboard wire as well. Seems I misread the stackexchange answer and was generally a bit dim - TXshield → RXarduino and vice versa, after all.

I’d also absent-mindedly wound the other broken-out wire around the shield before plugging in, after which it wouldn’t work completely. I unwound it and it magically works a lot better…

After these edits connection success rate is 11-9 (Connect-Fail, respectively) for 20 tries of the basic MG2639_getinfo example sketch. Fails seem to be in clusters of 3 or 4 for the most part, though I may need to keep testing to work out if that’s due to anything that I can fix.

Generally feeling a bit silly, but the situation has been improved at least! Now if I could crack the baud rate issues that would be grand…