Dear All!
I have recently discovered Arduino and I am interested in using this for my small DIY projects in the lab.
Currently I am looking into building a gas mixing setup to control the humidity.
Therefore, I split the flow coming from a dry nitrogen (N2) line into two separate lines, run one line through a bubbler and unite them later on in a chamber with a humidity (RH) sensor. Further on the gas is released through a second port of the flow chamber.
Right now, all I can do is regulate the flow manually to reach a desired value for the RH, but I think it should be rather easy to automate this using Arduino (right?) 
can someone help me to find a suitable gas flow control component? For humidity/temperature sensor I already found a promising model (DHT11 - Temperature & Humidity Sensor DHT11 -Tutorial - YouTube)
But I am struggling a bit with finding a suitable option for measuring and controlling gas flow.
Your knowledge and help is greatly appreciated!
Yours,
Chris