Hmmm i recognise that handle! I use Roast Logger software, a BT thermocouple, and a variac on the fan and adjustable regulator and gauge on the gas.
Yep, I'm still alive and kicking. Been a while though since I been on here. Still roasting away and mostly drinking good coffee from the Caravel. As I work nights now, I am occasionally in a situation where I have to drink caffeine beverages that are almost completely unlike coffee. C'est la vie.
Its all manual control at the moment, to convert a gas fluid bed roaster to run on a PID is a pretty expensive and complex project - and I am not convinced its bang for buck. I do use the Arduino TC4 to run the TC to the Roast Logger app, so its possible to hook everything up - the gas controller is the expensive bit, about $350 or so, plus some other bits and pieces to drive it via the TC4.
Plenty of options for monitoring without implementing auto control. Just understanding how previous roasts went based on what you changed manually can be a big help. I used to monitor and record quite a bit (Bourbon on an Arduino/TC4), nowadays roasting is pretty much repeating what I did before with minor tweaks. If I ever do make a bigger roaster, it will be back to learning again.
I imagine airflow changes, even with a stable rate of rise would make quite a difference in a fluid bed. You should be able to put monitoring on the fan quite easily if you feel like it. It will be most interesting to see how your project goes now it is actually roasting.