Arduino configuration - HELP

Sorry guys if i put this topic on wrong place, i am for the first time here. And i hope I will stay :) I am going to buy arduino UNO with GSM shield. But I need some help. How is GSM shield comunicating with Arduino? I will probably need serial comunication for other purpose and hope that GSM is not using it.

Or should i just buy Arduino MEGA?

Usually the shield plugs into the Arduino. See the link in my signature on how they connect.

From the web page about the Arduino GSM Shield (http://arduino.cc/en/Main/ArduinoGSMShield) you can look at the PDF schematic to see what pins are connected to the Arduino. Looks like RX and TX are connected to Pin 2 and Pin 3. Pin 7 is optionally connected to a signal called PWRKEY. I think it can be used to turn the GSM board off and on.

You can look at the arduino products page and the getting started page. They will have some information for using the shield.

you can use a virtual serial on the arduino ,, so you can run 2 different serial ! :o

Looks like that GSM Shield (http://arduino.cc/en/Main/ArduinoGSMShield) is using Rx and Tx. In that case i would not have a spare serial communication port.

It would be the best solution to buy Arduino Due and GSM Shield. Am i correct?

lol . yes it need a tx rx ,,, and it uses this on pin 2 and 3 ,, so your serial pins 0 and 1 are stil free !

UNO has only one Rx and Tx (http://arduino.cc/en/uploads/Main/ArduinoUno_R3_Front.jpg). And if i am looking correctly GSM pins 0 and 1 are not connected (http://arduino.cc/en/uploads/Main/GSMPinUse_2.jpg)

Before you potentially waste your money, perhaps you could tell us what your other purpose is for the serial port. You may have difficulties using the serial on the UNO as it's connected to a USB chip.

UNO has only one Rx and Tx (http://arduino.cc/en/uploads/Main/ArduinoUno_R3_Front.jpg). And if i am looking correctly GSM pins 0 and 1 are not connected (http://arduino.cc/en/uploads/Main/GSMPinUse_2.jpg)

yes so you can stil use your serial ,,

Dexterbot:
yes so you can stil use your serial ,

NC (not connected) means that pin marked as NC dos’t exist

KenF:
Before you potentially waste your money, perhaps you could tell us what your other purpose is for the serial port. You may have difficulties using the serial on the UNO as it’s connected to a USB chip.

second serial is ment to be modbus rtu (slave)

Thank all of you for your toughts. I think i found my solution. I will buy Arduino UNO, RS485 Shield and GSM Shield.

RS485 Shield - I can choose two pins from Arduino’s D0 to D7 as Software Serial Ports to communicate with the shield and i will use it for modbus comunication (https://www.sparkfun.com/products/12965)

GSM Shield - I can use SoftwareSerial on pins D7 & D8 to communicate with the shield (http://www.simpasture.com/36023.html)

Special thx to dannable for hes tutorial. Looks rly nice. Can’t wait to get my parts to start experiment :slight_smile:

Sorry Dexterbot for missunderstanding :frowning: you where right about the software serial