On vacation it’s nice to remotely check on your refrigerator / freezer to know it is operating normally and not return home to a power outage and rotten / spoiled food in the unit.
This Arduino-based controller uses two DHT21 temperature / humidity sensors, one for the refrigerator and the other for the freezer, configured as a web server so you can query it with a browser at any time.
With a normal setting of 0 F degrees for the freezer and 35 F degrees for the refrigerator, any reading beyond +/- 5 F degrees may be cause for concern and a quick phone call to a friend near your home to check on conditions.
If you cannot query the monitor it may indicate a likely power outage. A quick phone call can save the day (and your food).
Notes:
- Set up a static IP address and port in you router
- For remote access, use a DDNS (Dynamic DNS Server) such as Duckdns.org (free).
Left to right: 0.96 inch OLED screen, NodeMCU ESP8266 (built-in Wi-Fi)
DHT21 temperature / humidity sensor velcroed onto inner wall of the refrigerator. Similar one velcroed onto inner wall of the freezer.
=================
Screen shot
Temp= 3.20F Humid= 99.90
Temp= 39.92F Humid= 99.90
=================
