I wonder if you could use an Arduino and then write an application for a PC to control the machine?

This example controls two relays from a PC software application: http://startingelectronics.com/projects/arduino-projects/arduino-tiny-relay-shield/

And this one reads a temperature sensor (maybe you can switch the machine off when the ice cream is cold enough?): http://startingelectronics.com/projects/arduino-projects/arduino-tiny-temperature-shield/

They both use the Processing language for the PC application and an Arduino.

Just my 2c worth Smiley