Quick n' Dirty Freezer Door Alarm

Description

My fridge tends to work it's way up against the wall, and the freezer door will occasionally get stuck just before closing all the way. Food melts. It's a bummer.

I rigged up an alarm system using an ESP-32, a reed switch, a magnet, and a LiPo - all of which I had sitting around, fortunately. The magnet attaches to the freezer door, and the reed switch + ESP-32 sit across from it on the roof of the fridge. The ESP-32 wakes up every few minutes to check the switch. If it detects an open switch on two consecutive checks, it assumes the freezer has been open for more than a few minutes. It then connects to WiFi and triggers a notification!

With a wake-up period of 120 seconds, a 400mah battery lasts a bit more than 3 weeks. Eventually I'd like to set up a low battery alert as well.

Full instructional video below!

Components

1 × ESP-32 "Lolin-32" board with built in battery connector / charging circuit. Any web-connected board will do.

1 × Reed Switch

1 × Magnet Inductors, Chokes, Coils and Magnetics / Fixed Inductors, Chokes and Coils

1 × Lipo Battery I used the 400mah "Ideal for Feather" battery from Adafruit. Fit nicely.

Build Instructions

Collapse

1

Connect one of the reed switch's terminals to a GPIO pin on the ESP-32

You should make sure the pin matches the number specified as `SWITCH_PIN` in the Arduino code.
2

Connect the other reed switch terminal to the ESP-32's ground
3

Load the ESP-32 Arduino code onto the board

code: https://gist.github.com/dupontgu/8efcca2611103104eda88f33fd578c71

ESP-32 Arduino setup: https://www.hackster.io/abdularbi17/how-to-install-esp32-board-in-arduino-ide-1cd571

View all 7 instructions

Discussions

Dan Maloney wrote 11/16/2020 at 23:16

Quick and dirty, I love tactical projects like this.

My freezer problem is a little different -- freezer is in the garage, and if the compressor fails or the breaker trips, I'll never find out about it until hundreds of dollars of food are spoiled. I might try something like this, but with a temperature probe instead. Plus a door-open switch that texts every time someone opens the freezer, just as a "positive control" that the whole system is working. Think I've got everything I need to make that happen right now.

Thanks for the inspiration!

Are you sure? yes | no

Guy Dupont wrote 11/17/2020 at 02:34

Thanks, Dan! I dig the temperature probe idea. Now I'm kinda curious how quickly the internally temp actually goes down. Also - "Think I've got everything I need to make that happen right now." - isn't that the best? I've only recently gotten into this territory.

Are you sure? yes | no

Quick n' Dirty Freezer Door Alarm

Become a Hackaday.io member

Just one more thing

Description

Details

Components

Build Instructions Collapse

Enjoy this project?

Discussions

Become a Hackaday.io Member

Does this project spark your interest?

Report project as inappropriate

Send message

Remove Member

Build Instructions

Collapse