How to automate my Harman p35 through the thermostat connection?

[schmobodia]

I’d like to be able to control my p35 through my home automation platform. I have it on a smart switch, but this doesn’t allow the stove to do its “cool done” process.

My stove has the small room sensor, but it would appear I can use an alternative “thermostat” connection.

But what sort of control would I need for this? What does a thermostat typically output for a signal to active the stove?

 

[Mt Bob]

Use search box above, type in Harman thermostat, and you will find tons of info.

 

[Urbanhopper]

I've had mine running with a millivolt programmable stat for nearly a decade and no issues. I recently connected a Nest using a 24vac relay and it's just fine. Now I can actually get data on how often it duty cycles and control it from anywhere. See attached photo for wiring to Nest, relay and room temp sensor (TC).
I want to connect a smart switch next to the igniter and have full control to turn it on and off completely.