Arduino Curing Chamber Setup

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kosap1

Newbie
Original poster
Apr 8, 2015
14
11
San Antonio, Texas
Hi all!

I'm new to this site but not to the activities. Recently I got a bug to start making salami and the holy grail, a dry cured pork leg. The pork leg will be down the line but this weekend is salami weekend! First I had to make a curing chamber. I decided to go with a custom designed system vs. the normal Johnson controls and humidifier with humidistat setup. This give me some more insight and control into what is happening inside. 

I built the sensor system using an arduino mega, a DHT11 humidity and temperature sensor, outlets, a bunch of wire and solder, relay shield, ethernet shield, pair of netgear range extenders, and some general building supplies.

The system pictured below is version 1.x and needs a few more modifications before I consider it 'done' but it works as it is supposed to. Version 2 will probably be cleaner looking and not so diy in nature.

This picture is of the front of the unit. It displays the current temperature, current humidity, what the temp range is (I have the code set up so that the temp triggers the fridge 'on' once the warmer threshold is hit and turns off once the colder one is hit), and what the humidity range is. 

There are also 4 leds there to show me what outlets currently have power going to them. Right now in the pic 'pin 7' is on and that is the humidifier, which you can see in the lcd output that the humidity is at 69% and it is set at 70%, so that is correct.


This pic is the side view where the outlet is (there is another outlet on the back, looks the same as the side)


This is the other side view, where all of the external wires come in. 

The yellow is a network cable, that allows the device to connect to the internet

the black just below the yellow is the usb cable for providing power to the unit.

The three smaller wires on the top right are the three wires for the temp sensor, these run to the inside of the fridge

The big black square, carbon fiber looking thing is a safety switch that cuts the power to the whole thing. I put that safety on it becasue I had it lying around and it looked pretty cool. :)

and the bottom right is the power cable coming in.


Here is an inside pic. You can see the netgear wireless range extender (it is in my garage and the wifi card was quite a bit more, so I used a wired ethernet card with a pair of range extenders that weren't being used.

You can also see all of my awesome wiring! Like I said, it is a little rough looking but it all works. :)


And the inside of the fridge, with the temp sensor hanging down and the humidifier sitting in there. 


Now for the real fun stuff. The main reason I wanted to do this was becasue I wanted to see the data behind what was going on in there. 

Here is a link to my google spreadsheet. The device auto-uploads all of its sensor readings to a spreadsheet that I can see from anywhere. 



the first sheet is the raw data, the second (called 'results') are a few graphs and whatnot of the data. 

When I wrote this up it had been running pretty constantly for 42 hours and had an average temp of 53 degrees F (was set on 55) and an average humidity of 74% (was set on 70)

Future additions:

In the next few weeks I'm going to track the data changes and make changes in the code to make it more reliable. 

I'm going to add weight sensors that will each hold a separate link of salami. I'm guessing I can fit 5-6 sensors in there. So that I can take a reading on the salami's weight every 5 minutes for a month. More to come but those are the ideas for now!

Anyone else think of anything I can track?

I also have a smoker and am thinking of building a similar system that tracks ambient temp from a few places in the smoker, the inside temp of the meat and outside ambient temp. 
 
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That looks like a nice setup.  I was thinking about setting up something just like it.  I do like the idea of the scales.  You asked about another Idea to measure and I though about PH.  I know there are probes for that.  Although I think the PH is important during the fermentation stage?

Curious, did you program it or download the source?  I found a couple of links while searching the "google"

Arduino code for maintaining temp and RH.
https://github.com/chennes/CuringChamberControl

Thanks for your post.

Aaron.
 
Hey all, sorry I haven't responded in so long. I travel a lot for work which was part of my requirement to have this self report to Google Spreadsheets. 

@Diesel  - Totally right on the PH. There are sensors and anything that has a sensor is something I can use and graph. Someone that knows more about salami making can chime in with all of the specifics but the ph is really important in the fermenting stage of the process. And I actually wrote all of my code. Which was a fun project since I don't really code but am in the tech industry so am familiar with what needed to be done. 

Can anyone give me any tips - My humidity is not decreasing it is running at around 85-95% and hasn't come down. I have the humidifier inside of the fridge but it doesn't even kick on because the reading never falls below the set h. is this a problem?

my data (use the third tab 'Results'):



I think the issue is the cooling element on the mini fridge causes a lot of condensation. Now I didn't have this problem before I put salami in it but now that there is salami hanging that's whats happening. Any tips?

And here is a pic the day the salami went in:

https://www.dropbox.com/s/u6okxeg79qgr51k/2015-04-11 20.39.56.jpg?dl=0

Here is the recipe I used:

http://honest-food.net/2014/08/07/basic-salami-recipe/

should have cut up more fat vs grinding it though. I think the next batch I'm going to do that so I get much more variations. 

Thanks for looking at all of my stuff and giving me your opinions!
 
kosap, I have the EXACT same problem with the higher humidity in my little wine fridge drying chamber. It sits around 80-85% without me doing anything. The reason is because of the condensation the cooling coil creates. I can literally see water dripping down the rear of the fridge from it. Now those numbers are actually perfect for me. My suggestion would be to remove the humidifier all together and track the numbers. If they stay around what mine are then there's no need even to have it in there. Just open the door a couple times a day to get some new air in there and you'll be good to go.

As far as the hand cut fat versus the ground, that's going to be a preference. Some recipes will call for either and I've done it both ways and like it both also. The hand cut is of course going to create a much greater texture difference and visual look to the finished product. At the same time, if you're not using good fat for that part, you might get some chewy spots because of it. I tend to grind now because I can't get pork fatback here. My fat comes from the fat portion of a pork shoulder. I say try it both ways and see what you like.
 
Good morning..... Disclaimer.... I don't know squat but I am trying to learn about meat drying chambers....

I have looked up saturated solutions for humidity chambers..... Ammonium sulphate, in a saturated solution, maintains a RH of 82%....

That may be an alternative for small units... And the humidity range is 82% at 5 deg. C... 81% at 20 deg. C.... and 80% at 35 deg. C....


Ammonium sufphate is readily available as a fertilizer and should be adequate for this type use.... Distilled water should be used in the saturated solution...

 
thanks Dave! that definitely looks like an option. The other thing I did (again I was out of town for 9 days for work) last night was to install a small dehumidifier. Which paired with the moisture my fridge creates seems to be working. the setting is currently set at 90% RH and is averaging around 83-86% over an 8 hour period. 

Can anyone look at my pics and tell me if the salami looks ok? There is some mold developing and I'm hoping it is good mold and not bad mold. The other thing I did was to make a little umbrella

device for the fan and for the de-humidifier since they were getting wet from the fridge, didn't want them to short out. Just welded a small steel bar together to get the umbrella made.




 
Did you spray them with any sort of Mold 600 culture? This culture includes a mold that will cover the entirety of the salami with a white layer that helps with even drying and protection.

They are looking to be coming along nicely. The mold that's currently on there isn't really bad, but it's not a helpful one either and should be wiped off. Mix 1:1 parts white vinegar and water together and then just use a paper towel to wipe it all clean and then rehang.

From my experience and reading, white is Good, green is Ok, and red and black are BAD.
 
Wipe down the entire inside of the fridge while you are at it with the vinegar solution... I would remove all the stuff not needed.... shelves etc... Ricky had a very good suggestion about spraying mold 600 on the links.... it's an edible white mold that looks pretty cool when it gets established...
 
@atomicsmoke  no red mold! mostly white with a little green. but I think that may be due to the higher than desired humidity level. I fixed that by modifying my code and putting a dehumidifier in there. 

@rgautheir20420  thanks for the analysis. Will be wiping them down today and ordered some 600 which will be here tomorrow to get a nice coating on them. 

FYI, my next modification is to add the weight measuring system to the setup and then v3 is going to include a camera and light that will take a picture once a day and post online to make a nice timelapse. 
 
Hmmm I'm thinking all my help might earn me at "at cost" setup shipped over 
bluesbros.gif
 
Haha, We'll see. I don't even know what my 'cost' is at this point. And I do want to post everything about it on here but want to make sure it is 100% first. So I'm still working out some kinks. 
 
 
Haha, We'll see. I don't even know what my 'cost' is at this point. And I do want to post everything about it on here but want to make sure it is 100% first. So I'm still working out some kinks. 
It's a cool project none the less. The 2 things things that interest me the most are the temp/humidity tracking and the weight loss tracking. What device do you plan on using to do that?
 
the main 'brain' is this: 
and then I just add sensors to it. So for the weight part I have to order one of these:  and one of these to interpret the signals: 
 One of the above combo per salami. 

And then I have to weld together the bracket for the weight sensors to be installed properly so they can hold the salami and take accurate readings. 
 
How many addons of these sensors can that board take? It's already got a few sensors attached considering the temp and humidity right? So you're looking at $20 per weight sensor setup not including the bracketing setup also. 

I wonder if it's possible to take one of these http://www.ebay.com/itm/like/271774281162?lpid=82&chn=ps and remove the auto off function? This would be a reasonable addition to a setup. I know it wouldn't be reporting data anywhere but still easy to monitor the weight loss.
 
temp and humidity are integrated into one sensor. :) 
and I know it seems like I know what I'm doing with this project but a lot of it is trial and error. I don't even know where to start with that scale you pointed out, if I wanted it to report data, which I do :). One thing that I can say is that I'm trying to keep as many electronics out of the actual chamber as possible since it is warm and humid in there. The $20 option leaves really only the aluminium weight sensor and some wires that run out of the unit actually inside. the little interface board that I shared is mounted outside. I have a 3d printer so once the final version with weight sensors, and a camera is done then I'm going to print a board that nicely holds everything and an enclosure to keep it all safe. 

And the real end goal here is to but a big fridge and make it have all of these cool things going on. Thanks for everyone's input!
 
Today I got the weight sensor in so I welded together a nice new hanging bracket that I can bolt the weight sensors to but will also hold the hooks nicely. Here are some pics...

Notice the condensation from the fridge, that is actually helping me, now I'm controlling the RH with the de-humidifier! and it is going great!


pic below is my new bracket. Had some extra threaded rod in the garage so I spent a few hours today welding it into a nice bracket that slides right into the fridge. 

 
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