Any Arduino Programmers In The House?

[chilllucky]

I am going to try to build an automatic flue curing chamber for next year's crop of home-grown Virginia Tobaccos. Growing the plants; I have one year of experience at. Building a box; I have many, many years experience doing. Getting a computer to take temperature and humidity readings and turning things on and off to hold those values to a schedule that changes over time? The thought of it gives me an ulcer.
Is there anyone in the community here who can/does/likes to mess around with this kind of thing? I'm checking here first because I'm hoping to exchange the product of my hobby for the product of yours.
Message me for details if you're interested.

 

[elessar]

I have done some arduino programming in the past as I built a 3d printer that runs or at least loads software through arduino. Programming a couple PID routines shouldn't be too bad. Can I ask what devices you wish to control to achieve temp and humidity goals? Also how complex is the schedule? Perhaps actual stand alone PID controllers would work without the need for any programming, other than setting them up. You wouldn't need a computer running either. I built a beer brewing machine for home brewing that uses PID control through a solid state relay to control heating elements. Very easy setup and quite accurate. Might be another route for you.

 

[bigtex]

I started building a bbq pit controller with an Arduino, then we moved and it is still in storage. You can find lots of code online to run. It may be easier to modify an existing code to take input from a thermocouple and hydrometer and control fans and/or heaters with a pwm output. Good luck!

 

[danimalia]

You may want to check in on some cigar forums as well, since I've seen guys do similar projects with humidors.

 

[chilllucky]

Here's a curing schedule. There are three factors that make me want to go full-auto: First - the chamber will be in a shop I rent space in, I will only be able to check on it once or twice a day during the cycle. So manually advancing a thermostat will not work. Second - the two big temperature ramp-ups in the schedule are supposed to happen one degree per hour over twelve hours then hold, then advance again. That's more steps than any PID thermostat I have seen can handle. Third - humidity is controlled by closing (which increases the humidity in the system) or opening (which allows fresh air in and decreases humidity) some kind of blast gate/vent door via solonoid.
Fourth - a fully automatic flue curing chamber. C'mon, that's awesome.
A dream ask that I haven't seen on any other home or commercial automatic systems would be a scale, rather than a clock, that advances the schedule. Moisture content of the leaf, by weight, is the indication that it's ready for the next phase.

 

[cosmicfolklore]

There is more art to curing then just plain science. You will find that not all leaves harvested at one time will all follow the same schedule. I do mine at 98 for the first day, check them and then maybe let them stay or decide to ramp it up. I found all of the graphs and charts to be useless for me. I just use crock pots and a heater (for the final push).
But, since you've never done this before, maybe you should just follow the charts manually, before getting expensive with it, and then alter your time and temps as you tweak your own schedule.
My mistake was in ordering digital controls for my flu kiln also, and they are still in the boxes. It's just much easier than all that you have read leads on.
Keep in mind that the guys who started flu curing just had a barn... and a fire.

 

[chilllucky]

They also paid a guy to stay awake for three days at a time stoking that fire and doing visual and tactile checks on the tobacco from various ports in the barn. That's historically cool, but time I ain't got. Modern commercial crops are cured via automatic controls in a shipping container sized box. They probably throw away more leaf than a good barn cure-er would, but they are also planting with better yields.
I'm just screwing around with a dozen plants here.

 

[elessar]

Since you are doing this in a remote location, perhaps something like this would work: https://www.auberins.com/index.php?main_page=product_info&cPath=37&products_id=642
I have used this company for my beer brewing controls. Not high end stuff, but hard to beat their prices. Also, they do have a PID controller with ramp/soak control which can follow your schedule. With the Wifi (if available where you are curing) you could control this setup remotely.
None of this addresses the weight of the tobacco but that would be doable as well. I can't comment on how a schedule will affect your results as Cosmic pointed out.

 

[cosmicfolklore]

I'm just screwing around with a dozen plants here.

Even more reason not to invest too much money and time in controls. I promise you, it isn't going to be that complex. I merely let mine stay in 98-100F with whatever humidity the crock pots put off, and then crank up the temp to 120F until it is done. Then you can think about the color cure if you want oranges, reds, or browns after that.
You might want to check out the youtubers, instead of the big industrial curers. You can see that people are getting awesome results without all of the technical gibberly gook. And, you will find that getting too nerdy with this will not make anything better. It's like worrying about the trajectory, coordinace, and geometry before hitting a golf ball. Trust me, you will get better results than these big commercial assembly line guys. "Home cooked" is always better than "store bought."
and, the only reason they had to hire people back "in the day" was to keep the fires going, as they weren't measuring anything, especially humidity, and probably not even temperature---since, they couldn't control the temperature of the fire.
Trust me, trust me... this is not rocketscience. You will throw away all of these charts and crap after you give it a try.

 

[chilllucky]

Eleassar - that thing looks really cool, and so close to what I need. The issue that jumps out at me is that the relative humidity in this chamber is not controlled by a humidifier and dehumidifier (I would need both) but by closing and opening some kind of vent. What you've linked to could probably be made to work with that, but I don't know enough about electronics to say for sure. Also, there is WiFi at the location, tho I don't know if I wanna wake up every hour overnight to up the temp 1° by the app.
Cosmic - I get what you're saying, but I'm still gonna give this a go. It will be 5 years minimum before the tobacco field, curing apparatus, and I all live at the same address and I can reliably check in on the process and get a proper feel for it. In the meantime, I think a automatic system is a. Really neat and b. My best bet for getting _some_ quality leaf out of the garden.

 

[cosmicfolklore]

Cool,

just keep in mind that the initial color cure that removes all of the chlorophyll is not the same length of time for all of the leaves. The first primer leaves will just need a a few hours, while the thicker middle of the stalk leaves will be thicker and heavier, and may require more than one day, while the top leaves are more delicate, similar to the primers. And, sometimes you will have a mix in the kiln. Without being able to look, I would be at a loss for what to do. This is why I keep built my kiln net to my house, so that I can check the water level of the crock pots and keep an eye on the load to know when to ramp it up.

But, you will better know what I am talking about when you get it running.

 

[elessar]

What you are looking for is a powered damper of some kind (or multiple if needed) with or without a separate fan depending on your setup. You would then just use the 110VAC output of the humidity controller to trigger a relay with a 110VAC coil switching 24V power (from small transformer) to the damper. Many dampers use 24V. You can use a power open/spring closed damper or a power open/power closed damper with a double pole double throw relay. This would basically always power the damper but when wired correctly it will reverse polarity depending on if the humidity control is supplying power or not. Sound complicated but it is very simple. The power open/power closed dampers draw much less power. THe spring style will either open of close (depending on configuration) when the power fails or is turned off.
One thing I can't answer is if the app control can do a temperature ramp/soak. You would need to contact Auber for that. That would really check the boxes from what you have said about your application.
Is the humidity in this case a secondary effect of the temperature and the time at temp or do you need to actually hold humidity at certain points? To word it another way, if the tobacco was heated according to your temp ramps in a relatively well vented box, would the humidity follow the dotted line on the chart on its own (only theoretically of course)?

 

[chilllucky]

Eleassar - No, unfortunately it wouldn't. From what I've been able to learn so far (still plenty of learning to do) during the first "yellowing" phase you want high humidity and the lowest temperature of the cycle. The reason is the same as watching the water temp in your mash tun. You're converting starches to sugars by making an ideal environment for an enzyme to do it's thing. Technically, the leaf is still alive in this phase. It looks like most folks have to add water to the system at this point, as the leaf will soak it up before the environment does and it can be read by a humidistat. At the hobbiest level, this is usually done by filling a crock pot or an open pan inside the chamber.
The next phases have increasing temperature and decreasing humidity. They are meant to get to the optimal environment for one other enzymatic reaction, then to kill the leaf and dry it and finally the stem out. It might work out on paper that a fixed amount of water would carry through that whole process, because relative humidity would go down as temperature rose in a perfectly sealed system. But I doubt I'll achieve that.

 

[elessar]

No problem, I was mostly being curious. Opening and closing a vent via means of a powered damper should be no problem. They are available in a wide variety of sizes as well. You could technically control a crock pot and vent/damper with one controller output. When it is energized the crock pot turns on and the vent closes. When it is off the crock pot shuts off and the vent opens.
If that app controlled unit can do ramp/soak I think you would be well on your way. If it does not, you can use a ramp/soak PID controller to run the fixed temperature schedule (read the manual first to make sure it can handle your temp schedule before buying) and the wifi temp/humidity controller to monitor remotely and control humidity. That should cover you if the wifi unit does not do ramp/soak heating schedules. You would still have to set the humidity but I can't imagine the humidity would ramp very quickly.

 

[chilllucky]

I'm flattered that you think I could get anything besides a headache from trying to read the manual for such a device.

 

[craiginthecorn]

I use Inkbird temperature controllers for my fermenter, keezer, and wine fridge. They also make humidity contollers. It sounds like you are hoping to do something a bit more advanced, but Inkbird sells a combo of two separate controllers. You simply plug in the device that should turn on when temperature or humidity is too high or too low. For example, on my fermenter I have an electric heat belt and a pump-driven liquid cooling coil. Too cold and the warming belt outlet receives power. Too hot and the pump outlet receives power. Settings persist after a power outage, btw.
Amazon link