Our seconary freezer is located in the basement in a separate room where we hardly ever go. A while back my wife left the door ajar and after about a week needless to say nothing in there was edible. Lost probably a good thousand $ in food.
So I want a freezer alarm that can email me as a buzzer unless located upstairs will not work plus if we are away then we will always get a notice via email.Used a io link 2450 combined with an adjustable temp sensor which I dialed down to -10C since a freezer normally operates at -18c. At least this way if we keep the door open a bit we are not getting false warnings. Temp sensor link. https://www.amazon.com/gp/product/B07CH ... UTF8&psc=1. Purchase a small 12vdc 1 amp power supply and hooked everything up. You will need to drill a small hole in the freezer to insert the temp probe.
Set up a trigger to send an email to me when the IO 2450 receives a contact closure signal which the temperature board will do once the setting you have set is achieved.
Here is the preliminary project before I make it pretty, maybe will just leave it like this. The read out you see is the present room temp in C, you can see the probe to the right of the picture which needs to be inserted into the freezer. Works very well.