This is the arduino based airflow controller so far.
So I have an Arduino Nano on a mini-breadboard, controlling an external temperature/humidity sensor, a relay (to switch the fan on), an IR proximity sensor (to detect when the UDS lid comes off), the Maveric ET-73 pit probe, and a bluetooth transmitter/receiver which is transmitting all the data to the Android tablet you see in the back. This is all being powered by two 18650 2400MaH lithium ion batteries - these are 3.7v each. I'm hoping this will last for 12-18 hours - if not i'll double up with 4 of these, or look into some power saving techniques on the arduino by putting the processor to sleep when it is not being used.
At the moment the probe is giving some odd readings - i'm guessing because it is not hot enough, it is outside its range and giving these spurious readings. If so, i'll have to take care of that in the code.