I am studying an electronics course at School of Electronics and Aaeronautical Engineering (SEAE), military school. As a projects i am to design and make a freezer alarm. This alarm has to sound a siren and flash lights when the door is left open for more than 20 seconds and the temperature drops out of the range -20 degrees to +30 degrees. If you have any suggestions or ideas of this project i would be greatful ![Big Grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)