This low cost AVR-based Sous-Vide Cooker is able to auto-calculate the appropriate time for cooking a certain thickness of meat using heat transfer equations. It can maintain a set temperature for extended periods of time. The project implements advanced features such as a water level monitor and automatic timer that can set cooking times depending on the quantity of food cooking.
To monitor the temperature of the water, the immersion cooker project uses solid state temperature sensor with tight degree accuracy. LCD is used to displaying settings information and current temperature and keypad for inputting settings. To control the immersion heater and water pump, we opted for using a junction box with standard wall plugs controlled by a relay module. This would allow us to change what kind of heater and pump we could use, said Harrison Wong and David Diner, the project designer.
For more detail: Auto Sensing Sous-Vide Cooker using AVR microcontroller