I am planning to assemble a barometer (and ultimately gather temperature and humidity data as well) on Arduino, and upload data feed to my computer. Does PressureNet have an API to accept data from devices other than Android phones?
Almost. I'm working on this as almost top-priority right now. There are two APIs/SDKs that I'm building for pressureNET this week. The first is a customer-facing API to access the livestream data, and this is what we have in Beta right now streaming just to Cliff Mass. We'll finish that up in a few days, and move on to API number 2, which is what you're asking for. My first step is allowing other app developers to include pressureNET inside their apps, in order to increase the value of both projects. I will follow this by accepting data from other sources as well.
All of us who work on pressureNET are doing it in our free time as we all have day jobs, and this project currently does not generate any revenue. So you may wait a little while for the second part of that second API to get done. But on the other hand, we're open source, so if you're itching to get it ready you can help us out. :) The project is split into three repos on GitHub, we're going to merge the two servers into one sometime soon.
I've got all that working on Arduino as part of my coffee grinder data logger. Two temp sensors (ambient and burr temos), humidity, barometer, and a digital compass to log grind adjustemnts. It logs all that and motor on/off times to an SD card and squirts it out over USB. Let me know if you'd like to see my design/code. (email in profile)