Good afternoon. My name is Jeremy Trammell and I represent a group of designers and developers in Portland, Oregon (yup, completely snowed in right now). We have extensive experience with the Arduino platform, it's one of our favorite microcontrollers, and would be happy to assist you with your project. If I understand you correctly, all you're asking for is a function to take a floating point variable (which you have captured from your sensor) and convert it to a string of characters that you can upload in the send2pachube() function, yes? If that is what you are asking for, we can provide that in a matter of hours. Truthfully, this is a very trivial task and you should be able to find the solution online, but I'm happy to write it up for you.