I built a system like that for a gas kiln,
but the results were not very good because the sensor was situated in the kiln flue and the flames made the readings fluctuate a lot.
Also the common (cheaper) variety of sensors are very non-linear - i.e. they are designed to go from hard-on to hard-off, and you do not get much in-between. So the accuracy of your readings suffer.
I still want to improve on this but I am too busy with other things at the moment.
The newer "wideband" type of sensors are accurate and give a more linear output put the electronics to build one is more complex and if you buy a ready-built one (for cars) they are quite expensive (for someone like me).
- Mudlark likes this