Project Freezerburn

This project was originally pitched by Professor Sarah Mann for the IoT Club as a way to detect when her freezers were open. Sarah Mann owns a farm in Kentucky that has multiple freezers spread across several buildings, so any solution would need to be scalable.

@rweberhorowitz is our point of contact for Sarah Mann on this project.


  • Push notifications when freezers are left open
  • Status page where freezer status (open/closed) can be viewed.
  • Additional data when possible, including temperature over time.


  • Read switches to detect open/closed with magnetic force.
  • Roll ball switch embedded in door (requires door modification, may not be ideal on a climate controlled freezer)
  • Limit switch

Open Questions

  • What types of freezers does she have?
  • How many freezers does she have?
  • Can integrate with existing smart home systems, or use the Matter protocol?
  • Do we want an app to send push notifications?

Email Interview Transcript

  1. What type of freezer do you use (chest-shaped or upright)? If you have model number(s), that would work too.

2 freezers are uprights and 2 are chest-type

  1. Would each freezer location have access to WiFi?

The 2 uprights and 1 chest-type have access to wifi (these 3 are in my basement). The fourth freezer does not currently have access to wifi (this one is located in a different location altogether)

  1. How spread out are the freezers from one another?

The 2 uprights are sitting side-by-side and the 1 chest is about 12 feet away but all in the same basement. The fourth freezer is a few miles away.

  1. Is there adequate access to power at each freezer location?


  1. Do any of the freezers already have some sort of electronic display?


  1. How long are the doors usually left open to move product?

Usually just long enough to get something out for summer. A couple of times per year, they are opened longer when restocking, etc.


Pinout Information


Blue GNDchannel-N.C.

Yellow espGND-GNDchannel