This really sounds like a cool project, and may be used in various projects where the temperature needs to be kept under control. The temperature controller is based on an AT90S2313(ATtiny2313) and a Dallas DS1621 Digital Thermometer. The temperature is displayed on a dual 7-segment display, and two buttons are used for setting parameters. A high current relay switches the heating element. The displays are common cathode displays. The segments of both displays are tied together and multiplexing is handled in software. Note that the decimal point segment also are used.
April 13th, 2008