GSM Control of Furnace

Hello all. I’m a new user and just had a (hopefully) simple question for you. I’ve got a furnace at a cabin that I’d like to control remotely. I’ve come across some products that allow you to remotely control a relay via SMS or phone call. I was wondering if anyone had any ideas on how I could hook this up? I assume the furnace would need to continue to run, and I’d wire the relay to the thermostat input or something to trigger it to turn on?

I read in the FAQ not to post links so I will not link to the product in question unless you require more detail, but can anyone give me some pointers to get going in the right direction? Is control via GSM a bit overkill? Are there any SF products that would meet my needs?

Using GSM for a project like this is pretty common. However, if it’s not something you’re going to be using all the time, the cost of having a SIM card dedicated specifically to this may not be worth it for you. I’d recommend taking a look at the ADH8066 module: https://www.sparkfun.com/products/10138 and the SM5100B: https://www.sparkfun.com/products/9533. You can see how customers have implemented this in various projects by reading through the comments.

You could also use some kind of wifi interface if you have internet access as the cabin. The other option would be some kind of timer based system, but this would require knowing exactly when you’ll want the system switching on and off. You could alternatively have it be based on surrounding temperature or outdoor temperature as well. That would leave the system without any distance control, but might be an option for you.