Hobby photo developing can be a very complicated
  process. Film must be removed from its reel in complete
  darkness and loaded into a light-tight developing tank. In
  order to develop the film properly, chemicals must then be
  added to the tank, shook, and held still for varying amounts
  of time. This specific shake sequence is dependent on the
  type of film present in the tank and must be strictly adhered
  to. Otherwise, you run the risk of destroying all of those
  pictures from your fabulous vacation.

        The primary goal of this machine is to automate the
    shaking and resting of the developing tank, since this is a
    very tiring process to perform manually. Our 'auto photo' is
    designed to simulate the shaking motion by spinning and
    tilting the developing tank according to user inputs. The
    tank is spun and tilted by controlling a DC gearmotor and
    servo respectively, from the Handy Board. The system's
    control inputs include the total duration of the shake
    sequence, 30 second duty cycle (i.e. 50% = 15 seconds
    shaking, 15 seconds at rest), and also the spin and tilt
    speeds of the tank. With this control, the user can simply
    enter the sequence details, sit back, and wait for his or
    her film to develop.