Since i'm not happy with the thermostat on on my rv, I decided to build a new one. Basic Components are.
TinyScreen+
Custom Interface Board.
Major components on the i/o board are
2 NO switches
Opto Isolator with transistor output Or smt SSR
Connectors for power, output of Opto-Isolator and connection for DS18B20 temp sensor.

Program allows for setting Temp set point. Has predefined sleep mode, OFF/ON hysterisis, Attached is a pic.

Since i'm not happy with the thermostat on on my rv, I decided to build a new one. Basic Components are.
TinyScreen+
Custom Interface Board.
Major components on the i/o board are
2 NO switches
Opto Isolator with transistor output Or smt SSR
Connectors for power, output of Opto-Isolator and connection for DS18B20 temp sensor.

Program allows for setting Temp set point. Has predefined sleep mode, OFF/ON hysterisis, Attached is a pic.

Cool. what kind of heater is it?

Littlejohn,

It's actually not a heater, It's a refrigerator. Although with a mod in the program to change the allowable set point range, it could be used for a heater. Provided that the heater only required one closure contact.

Creating a fully fledged HVAC thermostat would also be possible, After all a basic HVAC thermostat is nothing more than temp measurement and outputs controlled by code.