1-Wire Thermostat with Programmable AVR

An Atmel AVR ATmega128 microcontroller contained on a single-board computer is the basis of developing a programmable thermostat.

The temperature is measured by a Dallas DS18S20 1-wire thermostat aside from the Olimex development board. The DS18S20 gets connected to the development board by using a standard PC floppy drive cable while the thermostat gets connected to the PC using a standard serial cable for monitoring and controlling the thermostat. The supply of the circuit comes from a 12V power source. The squid cable included with the programmer is used to connect an Atmel AVR JTAG ICE MKII programming and debugging tool to the development board.

There are 3 distinct controls for the thermostat. When the relay changes its state, the high and low set points of the device can be adjusted and controlled whether it beeps. When the southern button on the thermostat is held down, the low set point can be adjusted while the high set point depends on the northern button. The current temperature and set point on the thermostat are being updated by a simple thermostat controller. This also allows using a simple spinner controls to adjust the set points.