How does an automatic cold frame opener work to regulate the temperature inside a cold frame?

An automatic cold frame opener uses a temperature-sensitive mechanism to open and close the lid of the cold frame based on the temperature inside. When it gets too hot, the opener expands and opens the lid to let out excess heat. When it cools down, the opener contracts and closes the lid to retain warmth. This helps regulate the temperature inside the cold frame to create an optimal environment for plants.