It is a design of 4-channel thermostat with selectable operating mode.
The display used in this design is 4x20. Temperature sensors DS18B20. Control is carried out via 4 basic buttons:
There are also four additional buttons of quick access on the right side. All the important data is displayed in the main menu, and the configuration of individual thermostats is in the menu 1 to 4. Temperature is read by 1wire with serial read of individual sensors.
Settings:
- accuracy of the set temperature – up to 0,1 degree Celsius
- hysteresis accuracy up to 0,1 degree Celsius
- alarm in degrees Celsius (1 degree Celsius)
- operating mode selection – heating (for a boiler)/cooling (for a pump in central heating system)
- all the channels operate independently
The sensors are programmed by function buttons: F1 to F4 (four buttons on the right side). During programming, ID of the sensor is displayed and there is a sound signal after saving, and when the data is verified, OK is displayed.
Control is carried out on pins on the left side:
- T_1 Alias Portc.4
- T_2 Alias Portc.3
- T_3 Alias Portc.2
- T_4 Alias Portd.7
The circuit was made on Atmega32, and the program was written in Bascom.
Pictures:
Link to original thread (useful attachment) -
Termostat 4 Kanałowy DS18B20 LCD 4x20 Zadana i Histereza 0,1oC + Alarmy