Automated Temp Controller for BBQ Smoker

So I was asked by if I could make a cheap automated fan controller for use in a BBQ smoker. I used a microcontroller in a simple circuit to monitor the temperature of a thermistor, and then used the controller to adjust the speed of the fan. The main goal given to me was to make the fan cut off if temperatures exceeded 275F In the video below I tested the unit with a temperature set to 92F so that I could use my body temperature to trigger the fan cut-off point. 

I housed all the electronics into a a cheap Walmart dry-box. It didn't necessary have to be water-tight but I figured it couldn't hurt. I used a 3.5mm audio socket plug for the temperature sensor and a 2.5mm DC barrel jack plug for the fan power for easily plugging in the components to the controller.