View source for 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 (s, d)-tuples, where s stands for time in seconds and d for temperature in degrees Celcius. When started, the AVR should work through the list of tuples and for each tuple move to desired temperature d taking s seconds to get there.

The circuit uses an LCD display, a rotary encoder and two buttons for its user interface. The oven is controlled through a relay. Since the oven will be in a shed and the users would like to monitor the ovens progress from home, the controller will send its status periodically through a (cheap) 433Mhz transmitter. The  See the [[Wireless LCD display]] project (which is finished).

==Project notes==
* [[Media:max6675.pdf|maxx6675 thermocouple-to-digital converter]] datasheet
==Project Status==
;2010-06-23: Switched to AVR (from SX). Hardware platform now ready (max6675, LCD, LCD backlight control, rotary encoder, 2 switches, relay + driver, transmitter, receiver, led and programming header). First test with 'hardcoded' oven program successful. module tests of max6676, rotary encoder, LCD and relay successfully completed. Total hardware cost: around &euro;33,-, including K-type thermocouple probe.

[[Image:layout_oven_controller.jpg|400px]]
[[Image:oven_controller_top.JPG]]

[[Category:AVR]]