Home Monitor Cellular (Freeze Alarm)

I'm new to the Arduino world but have been playing with an UNO for a couple weeks now building basic projects measuring temp, automatic light switch, controlling lights from motion detection, and such.

My next bigger project is to build a project to monitor temp in a house that will be pretty well vacant over winter. I basically want to send a SMS or email message to my phone over cellular. Would like to get a text every 2 hours when the house gets below 45 Degrees F and every 15 minutes when the house gets below 38. I may decide to put a motion detector and have it fire a SMS if it detects motion but well see.

At this point I'm looking for your input on which cellular device to get that will work with my UNO but will work with bigger projects going forward. Long term I would like to get into home automation and maybe have the ability to send a text to the device and have it turn on lights in the house. I see lots of 2G GSM devices out their but as 2G gets phased out it might be better buying a 3G device. Ideally I would like a pay as you send SMS messages solution.


Why do you need to know every 15 mins if temp is below 38? It is most likely to happen in the middle of the night. Also the temp of the house is unlikely to change so fast that it would make any difference.

And what are you going to do anyway?

There are many projects using SMS so, do a search in the box at the top of the page.


15 minutes is probably over kill and Ill probably do more but with no heat an -30 degree weather the temp of the house can drop pretty quickly. Water in the pipes freezes at 32 so cant let it get that cold. I'd drain the pipes but the house is for sale so need stuff to work.

To answer what I'll do anyways. I'll call the neighbor or family that live close to the house and have them meet an HVAC guy at the house.

I do see projects with SMS however a bunch are using the SIM900 which is only 2G it appears and with 2G being phased out in many areas, I'm just wondering what the best cellular card currently is? Or if I just go with the something like the SeeedStudio SIM900?


if you can do wifi, you can host a web-site
then log all parameters

I unfortunately don't have n internet connection at the house any longer, otherwise that would be the ideal solution.

Gurufarmer, I am not used to those temps. My low temps may get down to zero Celsius very occasionally.