I've lost a freezer in the past and recently my buddy lost one with about 800lbs of meat in it. Nothing worse that finding that blood pool under a freezer and opening the door to warm temps and that awful smell. By then it's to late.

I made a micro controller (Pi3B) driven temperature sensor that now sends me a TXT message if the temperature gets warmer than -2F in the freezer. If I lose the freezer now at least I will have time to react. IT also saves the values every minute to a XLS file and I can compare external garage temp to internal freezer temp as well. Freezers in Texas garages work hard and they will fail and I'm fighting back.

Interface and readings


Prototype before making better plugs and a more robust housing.

Well that's cool. Good work

I think there's a market for that!!!

maybe - i went to buy one and there was no real commercial option. They have similar feature/function units for commercial and bio-medical but nothing for the average schmuck. The bio-medical ones are big $ since they also part of regulatory evidence chains for blood, tissue, specimen temps, etc...

There are plenty of DIY paths for this online w/ micro controllers, etc.. I built mine on a Pi and I'm actually having a daughter board printed so I can solder directly to it and attach directly to the GPIO pins vs. having the little nest-of-wires you see above. 10 was the minimum order and I am sure I have 10 buddies that would use this.

I will have 2 TRRS 3.5mm jacks for the 2 probes and a case w/ magnetic feet so it can just clip to the freezer. gen-2 will also monitor the current to the freezer in case it get's accidentally unplugged or a circuit blows, then it will notify on that as well. It's power requirements are very small so it will run inline w/ a small battery so that if it's AC gets disrupted it will stay alive and alert on that as well.

I really needed this a couple of days ago. I was working out of town and my wife came to visit me, for some reason the gfci plug that my freezer is plugged into flipped. She got a real nice surprise when she got home and walked into the garage.

Genius!

If a fella need 2 of those units shipped what would a round about cost be? That is brilliant.

the 2nd prototype is probably going to be about $150 in parts. instead of having both sensors and the resistors all tied in together to be a single power, data-stream and ground with the DB9-pin connector you can see i'm going to have each sensor with a 3.5mm male jack and the female's soldered into a board that will have a 40pin female adapter to ride the PI as a daughter board with the sensors and resistors inline... this makes it easy to switch out sensors, make it more modular and open the door for other sensors to be added (so instead of 2 temp sensors it can be 1 tmp and 1 humidity, etc...) as long as they all have 1-wire compatibility.. It will also have magnetic feet in the case to just 'snap-on' the freezer.

Power is light and i'll bring in the in-line battery as well so it has it's own uninterruptible power supply and it will still be very small

female 3.5mm jacks


pi layout

2.0 is almost done; it will have normal and warning operating lights that you can set to specific thresholds (red = warmer than -2F, blue = colder than -2F, etc..) and it still has the eMail and TXT functions. 3.5mm jacks are on their way for prototyping before they all get soldered onto that red board on the left. The temp sensors are those silver cylinders up top

Just an FYI. If you are not aware, do not drill a hole in any side wall. Most new freezers have refgerant line inside.

Before you make an investment in a patent search I bet it has been patented. I have shown two homes recently with Samsung refrigerators that have Wi-Fi. I have no idea what all they can do. But a temperature warning to your phone just might be one of the features, if not now then in the future.

I went thru the door for the exact reason you mention.

I'm sure there are smart appliances out there - this is more of a project for me and a few buddies that want one. I Have a smart-fridge at home and it does some basic stuff but it doesn't alert me other than audible alarms and frankly it's not a very useful feature. I've lost 2 freezers in the past and want to know when (not if) it happens again but in enough time to react and not lose my meat. It's a small niche market if anything at all.

Good work, interesting idea.

I would much rather an alarm or something else if the temp fell below x degrees than a text or anything linked to an excel sheet.

Have to be a hell of a loud alarm for you to hear it when you're away from home.

it has audible alarm, text and email capabilities so far.

i'm so sick of losing meat, it's happened to be twice, if I can i'll have it trip my dang ADT sensors too....

The final piece I wanted to work now works - I'll be making an enclosure next so that the whole unit is enclosed with (2) 3.5mm jacks for the sensors (I may put 4 jacks in case I want to add other sensors in the future) and LED's for operating status notifications. Case will have magnetic feet so it can just "stick" to the freezer and wherever it's best to drill the hole.

I lost a freezer full of shad before. Wow!!! Terrible smell.

That sounds awful.

I'll bet you could sell the s^*+t out of them on here. We all have meat in the freezer weather it be hunted or store bought. I would take 3.
Keep us posted.

I am getting closer to where I want to be - i've gone from that tangled spaghetti mess to having it now on a daughter board w/ the 3.5mm jack. I ran out of space on the 5-hole lines so I need to get a different style board to make the final multi-probe one but the concept and the way I will put the unit together is done.

The footprint is about 3.5 x 2.5x 1 and I need to get different posts to make the jacks lay flat vs. standing up.

and I probably need to learn to solder better.....

and for scale....