This is a gas valve controller for a Masterbuilt smoker. A circular set of "fingers" attaches to the gas valve and a servo controls the position of a valve. An Arduino reads the temperature from a thermocouple and adjusts the servo. A rotary encoder is used to set the temperature and tune the PID control parameters. An LCD display shows set temperature, actual temperature, servo position and battery status.
The servo slides parallel to the axis of the motor, on a pair of metal rods, to allow for motion of the valve as it opens and closes. The housing attaches to a base that is mounted on the control valve.