# How many functions can I put into an arduino uno? [closed]

Is it realistic to put the following: GPS module, GSM module, SD card slot and about 4 analog sensors into Arduino uno? (have not yet goten an Arduino in my hands).

• Find the datasheets for the different modules you want to use and the Arduino and add them to your question. Next find out from the datasheet which pins and interfaces are used for each shield. The short answer will be that you'll have a challange connecting them all at the same time, as many shields use the same pins by default, but I'm not saying it can't be done. In fact, in a case like this it makes more sense to use generic modules than to use proper Arduino shields, because you'll probably run into pin conflicts anyway. – jippie Mar 2 '13 at 16:29
• I have consulted, in prior exchange article just this. Where GPS and GSM shield used the same pins. The solution was bend the pins away when stacking so not to connect and use jumper wires, and redefine the pins in the code to what was jumped. – mpflaga Mar 2 '13 at 17:46

Third, will I have enough serials? I've only been able to get two serial connections working on the Uno (but I've been told you can get three working with some hassling). That is the hardware serial (accessed by the Serial object) and a SoftwareSerial object. The GPS will definitely utilize one of these and I bet your GSM module will use the other. Don't forget about debugging! Since you won't be able to have all three of these hooked up to your Uno I recommended debugging with the GSM module. Get this working and then move all your debugging code from Serial to your GSM connection. That way instead of using the Serial output on your computer you'll have to read from wherever your GSM module is sending data to.