I am building a curing chamber for charcuterie meats from an old upright refrigerator, I will post pictures once the project is complete. Mycodo has been a perfect fit for this, and I have successfully controlled the temperature within ±2 degrees. My challenge now is humidity control. Does anyone know of a small AC powered dehumidifier that would be suitable for an 18 cubit foot area? My other thought was to use an exhaust fan to control humidity, but I am concerned about the impact on my temperature.
There are many small consumer humidifiers on the market. If you look specifically for terrarium/reptile humidifiers, you can find some that have an integrated hose that will allow you to more easily plumb into your chamber. For example:
For reducing humidity with an exhaust fan, your consideration for controlling temperature will be the ability of your heating device to respond quick enough to the temperature change caused by the exhaust.
Yeah, I have some concerns with trying to do it with just exhaust. I have looked at some of these, but I have no experience with them, so it is nice to get opinions. Thanks!
If you are using a refrigerator, why not just run the refrigerator to remove humidity? Most refrigerators naturally remove humidity from the interior as they cool… and if your target temp is 50-60F for curing meats then it might be possible to run the refrigerator in conjunction with an exhaust/circulation fan?
I’d also like to place an order for a couple of pounds of prosciutto… haha just kidding
Seriously though… looking forward to seeing the photos of this project… I’ve often thought about building my own smoker/curing cabinet as well.
So I am close to completion and as it turns out, lowering the humidity is not an issue, because to your point, lowering the humidity jus happens when the fridge runs. The bigger challenge has been keeping the humidity high enough. That being said, just adding the meat to the chamber should help. On top of that, I have been running test cycles using this, USB Atomizer/Fogger, and it seems to keep up fine.
I think my final challenge is setting up the drying schedule. I want to use a time based system to alter my temperature and humidity setpoints, essentially creating “Curing Phases”.
With the great help and advice I have received here, I hope to start my first live trials this week!
Couple of issues with those cheap USB foggers you should be aware of:
1… like all piezo foggers, they have to be used in a very shallow pan of water or they won’t produce fog if the piezo puck is too deep, so the water will run out fast and require re-filling often.
2… there is no safety sensor shutoff on those cheap USB foggers… if the water runs dry, the fogger is still running and can overheat and become permanently damaged… or worse, start a fire.
They have these fogger kits with the water-proof pucks that have a built-in safety sensor that shuts off the fogger when the water runs too low. They also come with a float ring and holder cup that keeps the puck at the correct depth to produce fog, allowing you to place the fogger in a large container that doesn’t need to be refilled as often. I built the 5 gallon humidifier for my hydroponics system using these and it works very well.
However, for your use-case, I would really recommend a humidifier like Kyle posted… one with a hose so that the unit can easily be setup outside the refrigerator and refilled easily without having to open the frige.
For the Mycodo humidity control, all you need is a humidity sensor and a Bang-Bang Function.
Understood. I bought the cheap fogger to prototype the system. I created my own float ring for it so that I could use in in a 1 gallon container. I also added a float sensor to trigger a water valve on the outside of the fridge to keep the container full.
That being said, I do like the idea of having it outside of the fridge and will likely move in that direction as Kyle suggested.
I am using Bang-Bang for both the temperature and humidity control with an SHT31 as the input. I started with a DHT11 and DHT22, but the SHT31 reacts much quicker. Looking at possible upgrades there as well.
My next step is to create a series of time based phases for the drying cycle, something like this…
12 hours 90% RH/65F T
24 hours 85%RH/60F T
120 hours 80%RH/55F T
336 hours 80%RH/50F T
etc…
These values are currently arbitrary but good enough to paint a picture so to speak.
Ultimately I plan to add load sensors to trigger temp and humidity adjustments based on the delta between the starting weight and current weight of the meat.
The SHT3x is a good inexpensive sensor that works well in humid environments and doesn’t drift over time like the DHT or BME series sensors can do.
It may be difficult to get Mycodo to use timers that run for more than 24 hours. If I remember, the longest timer period that can be set is 24 hours… so if you need a timer that is longer than that you have to get creative with multiple cascading functions to make that work right. Or you may need to program a custom Conditional controller.
Or, you could use an external timer device that has longer timer functionality… such as an ESP32 running Tasmota, which has built-in timer functions not just for hourly triggers, but day-of-week triggers, and you could also easily use Rules to build even longer timer triggers based on dates, months, years, etc. You would program your timers in Tasmota, and either use one of the ESP32s gpio pins to send a trigger signal to the Pi’s gpio, or you could have Tasmota send an MQTT trigger to Mycodo over WiFi.
Using load sensors to measure weight might be more trouble than it’s worth, especially if you are dealing with a different weight every time… you would need load cells rated specifically for the weight you plan to measure. And you would need to re-calibrate the sensors and your delta-equation each time for each individual piece of meat. You’d also need S-Frame load cells, which are very expen$ive. I would think that there would be a moisture-probe sensor available that could measure the meat’s moisture content directly. (I believe they are called “grain moisture sensors”)
Haha, yeah the load sensors will definitely be more trouble than it is worth, unfortunately i have a habit of over engineering projects just to see if I can do it… I had considered a moisture sensor, but really haven’t found anything suitable yet. I’ll take a look at the grain moisture sensors, thanks for the tip.
Here’s a how-to I wrote about building timers in Mycodo for intervals longer than 24 hours…
If that doesn’t work for your use-case… then I recommend writing a Custom Conditional Function, or looking into getting an ESP32 and running Tasmota for it’s timer capabilities…
