I was thinking of a project for some of my more advanced students. I would like to send weather information from an Arduino based weather station to the classroom where the data would be placed into an Excel file. I was looking at this QRP shield, I realize that there are other ham radio shields, I am not set on any individual one at this point.

Here is my question. What ham radio information do I have to transmit with the weather information and what format does it have to be in?

Can I just include my call-sign with the serial data? Will having the transmitter randomly send my call-sign in Morse code be needed (not really random, at the end of each sending of information). I can see this working better outside of amateur radio bands. However,I am trying to decide on the basics at this point. I don't see many remote control toys around here so I do realize that I may be better off planning to use a hobbyist/experimenter band instead of Amateur radio (here is another example of hobbyist wireless, there are a lot of ways, or just use wi-fi); at the present I am just working on ideas and feasibility.

My concern here is how/can I do this legally.