A sensor to alart you to when the temperature inside a refrigerator or freezer has risen above a certain level. It is currently configured to turn on the alarm at 0 °C.
What is that perf board?
It is the Adafruit Perma-Proto Mint Tin Size Breadboard PCB.
Why did you do/use <THING> when <OTHER THING> would have been so much better?
This is my first real project with designing circuits and working with the Arduino, so there are doubtless better ways of doing it. I am more than open to pull requests with improvements.
Why didn't you use a board that has networking so that you could send out an alert via <SERVICE>, rather than just using a buzzer and light?
The building that I will be using this in is basically a Faraday cage, so there is no reason for me to do so.
Has anyone actually asked any of these question?
No, but the question and answer format makes it easy to explain things.
How many times did you seriously burn yourself while soldering?
Once.