Kiln temperature controller

General description

This circuit is intended to control a pottery oven. It uses the MAX6675 thermocouple-to-digital converter to measure oven temperatures. An oven schedule will consist of a list of (time, temperature) tuples. When started, the SX should work through the list of tuples and for each tuple:

• bring the oven temperature to the value given
• maintain that temperature for the time given

The circuit uses an LCD display, a rotary encoder, a small piezo speaker and two buttons for its user interface. The oven is controlled through relays. Since the oven will be in a shed and the users would like to monitor the ovens progress from home, the LCD display and speaker are wirelessly controlled through a 433Mhz transmitter/receiver pair. See the Wireless LCD display project (which is finished).

Project notes

• maxx6675 thermocouple-to-digital converter datasheet