Freezer Monitor DIY

double_d

Member
Joined
Apr 4, 2018
Messages
15
Location
texas
After I lost one of my freezers I used the Raspberry Pi platform to make a IoT device powered by Cayenne to live monitor my freezer and send out alerts to my phone and email if the temperature hit specific thresholds.

Mobile Phone Interface
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The original prototype looked like this
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then morphed into this
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That worked for a while but was a little expensive and the full Pi was overkill. Recently the Pi-Zero was released w/ headers and Bluetooth and Wifi and can be had for about $13. It's a much smaller form factor and allot simpler in terms of the Pi capabilities. Here is a Zero next to the full blown Pi.

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The 2 key components are 1-wire ds18b20 temperature sensors.

I had a custom PCB fabricated to hold 2 sensors connected to a 3.5mm TRS jack and 3 LED's for status lights (Red, Green, Yellow) to flag based on the internal temp as well - this gives a visual indicator as well as the app driven notifications. The custom PCB looks like....
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and put together (less the LEDs)
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This device will let you know if your freezer is getting warmer and gives you time to act before you slip on a puddle of warm blood and have to throw out all your meat. It happened to me and it sucks.

Hear is also a video where I was using Python vs. Cayenne as the drive

[video:youtube]

I had to order the minimum of 6 PCB's to get them printed so if anyone is interested in one and plays with the Pi let me know and we can work something out to get you one. You do not need the PCB if you want to do this project on your own, it just makes it more convenient.
 

phorwath

Well-Known Member
Joined
Apr 4, 2005
Messages
7,211
Location
Alaska
Is there a laymen's version?

I like the idea. Not the amount of time it would take to research the technical jargon to understand the content of your Thread.

How much $ to be functional. How complicated to set up and keep operational?

Does it require WiFi running full time to send the message to a smartphone when away from the house?

Does it use Bluetooth to communicate to the smartphone when the smartphone is close to the freezer? Like when I'm home?

Does the Youtube video explain down to the high school graduate level?
 

double_d

Member
Joined
Apr 4, 2018
Messages
15
Location
texas
The Raspberry Pi is connected to the internet and all of the alerting is done either thru Cayenne or a Google API is you use Python.

Laymans version - it's all plug and play with Cayenne and would cost about 50-75 bucks in parts if you connected the parts directly to the pins on the Pi. More if you used a custom PCB like the one I had printed to reduce form factor and keep it cleaner. It's internet connected and doesn't rely on phone proximity.
 
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