Hi,
I have an Arduino UNO and i want to make a small weather station. I have buyed this shield (SparkFun Weather Shield - DEV-13956 - SparkFun Electronics), weld it, and plugged it on my Uno. I also have the code that take the datas and display them.
My problem is that when my shield is plugged on the Arduino, i can't transfer the program on the Arduino. I've searched on the internet and some people had the same problem, the issue was that the shield is plugged on the Tx / Rx port and you can't transfer anything if they are in use.
I then proceed to remove the shield and the program succesfuly transfered. I have a message displaying on the serial monitor (a simple Hi, then the datas) and it's working. But i need my shield to be plugged so i can get the datas. The problem is that when i plug my shield on the working Arduino, the messages in the Serial Monitor stop and nothing is displayed. Even when I unplug my Arduino, put the shield and try to show the datas, it's not displaying.
I hope i was clear with my explications and i hope someone will help me 
Have a nice day
I've had a few problems when my Nano was connected to the computer, while a sensor was powered by external source (battery). The battery also powered the Nano via the Vin pin on the board.
After removing the external power source, it was connecting fine.
It is possible that when you soldered the header pins on to the shield, you created a short between Rx and Tx (pins 0,1) or from one of those pins to ground or to another pin. You can check the pins with a multimeter, and look carefully at the Rx/Tx pins on your shield to see if you can detect some problem. The shield does not have to be connected to the Uno when you check it over.
Do you have the optional GPS installed? Do you have the GPS switched to use Pin 4 and Pin 5?
If you have the GPS and the jumpers are set to use Pin 0 and Pin 1 you won't be able to use those pins for Serial Monitor (or for uploading).
hello mr.JOHNWASSER
is it possible to communicate data as Tx and Rx by not actually using the onboard Tx/Rx pins , rather employing them virtually at any other GPIO pins?
Shady27:
Is it possible to communicate data as Tx and Rx by not actually using the onboard Tx/Rx pins , rather employing them virtually at any other GPIO pins?
Yes. That is what the SoftwareSerial library does. http://www.arduino.cc/en/Reference/SoftwareSerial
Very interesting thanks for sharing.
I have the same problem not solved. 
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