Monitoring temps in outbuilding

Not sure if this is the forum to ask this in...mod may move if needed. Last year my son bought for me the Arduino Uno for me to play around with. One thing I'd like to be able to do is monitor the temps in my barn/shop. Since I have heat out there I'd like some method of tracking temps from the woodstove.... say the stove itself, chimney pipe....and air temp in the shop itself. I can install a PC in the barn and run cable to the house...or wireless connect to the house. Any suggestions from the group here?

Depends on the distances, and how easy it is to run wire. You can run RS485 with two wires over a reasonable distance fairly easily.

I'm about 65' from the building...a 4" PVC sewer pipe buried between the 2 locations. I also have electric and a internet cable pulled through that line.

20 m of RS485 cable should be fine, that was what I tested on that page I linked. Presumably one-way would be fine (just sending the temperature(s) ). When I say "RS485 cable" I mean cheap bell-wire or something like that. However if you already have the Internet cable I believe not all of the wires will be used, so you could borrow a couple of those. But if running 20m of bell-wire is easily done, I would probably just do that.

If you have an Ethernet connection out there, it would make sense to get an Arduino with Ethernet capability (there are several to choose from) and have it send the data back to a PC that can log and display the temperatures for you. You'd need to write/find an application on the PC to do that, but this type of application is quite common and I suspect you could find a working example either in the playground, or elsewhere on the internet.

DS18B20 temp sensors would be a good choice for measuring room temperatures - they're cheap and very easy to use, and don't need any calibration. They wouldn't read stove pipe temperatures - I suspect you'd need a thermocouple for that.

For the stovepipe, I recommend a Melexis 90614 IR Temprature Sensor (non-contact), it will read up to +380 degrees Celsius. If you do decide on it, and have trouble finding example code, I can supply you with code to read it.