Arduino Climate Control

I got my a/c, it is so tiny. It's a Frigidaire FFRA0511R1 5000 BTU. It is only 400 watts and has mechanical controls so that I can turn it on/off with my arduino. I like that it is only 400 watts because my entire setup needs to stay under 1500 watts since it is all on one circuits.

I plan to place it on a shelf outside of the tent and cut a hole in the tent. This is my air mixing tent, so the cold air will not blow directly on to the plants. Hopefully it will work out. Today got up to about 70 degrees outside, but the attic is about 85. I'm a little nervous to see what will happen in a couple of months when the outdoor temps hit 100.

I should have time to setup the a/c this week and bring up my veg tent. I'm also planning a 4th tent for drying. Since my 3 plants are all different strains, I imagine they will need to be harvested at different times.

The veg, flower and dry tents will all share the same air. It's not ideal, but I think it should be good enough. I'll just aim for about 75 degrees with 50-55% humidity.
 
@High Wally Thanks. It is certainly a bigger effort than I thought it would be. But of course I would do it again. I really enjoy growing.

Today I added a shelf in my air tent so that I could add a humidifier. In the picture the humidifier is black and on the top shelf. The white thing on the bottom left is the dehumidifier. And the skinny thing seen edge on on the lower right is the heater. They are all have manual control and are controlled by the arduino on the shelf on the right. Air comes in from the lower right and is aimed right at the heater.

On the right of the picture, the black 6 inch flexible duct is from the flower tent. The really big duct next to it is a house duct. Today I finally got a shelf that can straddle the house duct. Now things are looking much more organized as far as all the wiring goes. It took me about 2 hours to unwire everything, put the shelves up then rewire it. It is exhausting to work in the attic. But that is a price I'm will to pay for security.

I didn't really think my plants had as strong of a smell as I thought they would (its been 10 years since I've grown), they are in the 3rd week of flower. When I powered everything thing down, including the filter, the smell hit me. I guess the filter does a good job and having a negative pressure in the grow tent works. When I go into the attic I don't even smell a hint of what is going on. But I'm sure it also helps that the attic is ventilated with free air movement with the outside.

Assuming I'm not in too much pain tomorrow from today's activities, I will try to put a shelf to the left of the air tent to hold the a/c. There isn't enough flooring on that side, so I might have to improvise something. The flooring I do have is just thanks to the building code where there has to be a suitable work area around the furnace.

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I woke up this morning to see that my humidity was about 90% in the tent. I wired up my exhaust dampers and dehumidifier incorrectly before going to bed. To prevent this from happening again I implemented a manual override to turn on/off the relays and hooked it up to a virtual pin for Blynk to use. Now I can test all the relays while sitting in front of them from my phone. Now that I have Blynk as a tool, I'm finding all kinds of problems it can solve :)


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I'm not sure what I was thinking when considering putting another shelf on the outside of the air tent when there was an empty shelf on the right for the A/C :)

It was kind of sad to cut a tent, but I cut an X into to the side, so that in the future, with some duct tape it could be repaired. I pulled the flaps back and duct taped a seal around the inside of the tent to the A/C. Even though it is only a 400 watt A/C, I wonder what the start up wattage is. It caused my small pc next to it to turn off and thus all my arduinos connected to it turned off. I hooked up the pc to a small UPS and that seemed to fix it.

The downside to this set up is that the air tent has to be really close to the shelf with the A/C on it. And since all my electronics are also on that shelf I don't have a lot of room to maneuver.

I'm also concerned about the A/C venting hot air right into the electronics above it. I will add a temperature sensor to the arduino sitting above it to see if it is something I should be concerned about in the summer. I guess if I have too I can move the pc and arduino to inside the a tent so that it can enjoy the climate control.

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Finished tent

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I added the veg and drying tents. I now have 4 tents in this corner of the attic. 36x20 inch for flower, 20x20 inch for air, another 20x20 inch for veg and 16x16 inch for drying. I have a single 410 cfm 6 inch inline fan powering all the air. The air is pulled from the left side (dry and veg tents) and from the right side (flower tent) and connected via a tee duct to the single inline fan. Each side has a 6 inch carbon filter. Negative pressure is maintained in the drying, veg and flower tents. The air tent has positive pressure. I can see this while looking at the tents. The air tent is bulging (can be seen in the picture, it is the middle tent and the door is bulging out) and the other 3 tents are sucked in. All of this with the variable inline fan on its lowest setting. I guess I got an over powered fan for such small tents. The two tents on the left of the tee represent 4.5 square feet and the flower tent on the right is 5 square feet. Since they each have the same 6 inch carbon filter, hopefully the air will circulate both side evenly. This should be easy enough to tell once I get a temperature sensor in the veg tents.

It is starting to feel like a small tent village up there :)

Today I had to turn down my humidifier a little bit. For temperature and humidity I only turn them on or off once every 5 minutes. I didn't want to risk them getting turned on and off too quickly. So today the humidifier raised the humidity too much in its 5 minutes, then the dehumidifier lowered the humidity for the next 5 minutes. They did battle for about 30 minutes. To prevent this from happening again, I added a cool down period. If the humidifier just ran, the dehumidifier can not run for 15 minutes, but if in the next 5 minute block the humidifier wants to run again, that is fine. The heater and A/C will interact with each other the same way.


Tomorrow's project will be getting the veg room ready for growing by adding the light, arduino, fan and camera. I can't believe I will fill up my 8 port network switch up there.

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The last 2 days humidity has been really constant around 55% +- 4% which is what I have set for the target on the arduino. I recently added a humidifier to the mix.

I'm still struggling with temperature. The 200 watt cozy legs heater just doesn't seem strong enough to maintain much more than 10-15 degrees difference between the inside and outside of the tent. But it is certainly better than nothing. I'm going to try a 400 watt ceramic heater next.

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Normally the humidity change for inside (green line) only bounces a lot if I have the tents open and I'm working on them. Last night I had a lot of bouncing because the humidifier was going on an off a lot. I thought this could be because of an air leak. This morning when I check things out I saw that I forgot to close one of the ports used to pass wires. I did a lot of work yesterday getting the veg tent all wired up.

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Just curious, will you need to manually monitor the humidifier and dehumidifier levels, or is that something you'll automate? I'm probably going to need a humidifier, and thinking I'll never remember to check it on a consistent basis. If we can water plants, surely we can keep the humidifier full :)
 
RO water in your humidifier is a godsend. I made the mistake of using tap once and had to clean calcium dust off of everything!

I've got both in a tent, humidifier set to 45% (comes on at or below), and dehumidifier set to 55% (comes on at or higher). With the drain tube from the dehumidifier running to a floor drain. Really glad I took the time for both.

@bobinca is your temp swinging low at night and high during the day, or just one of the two?
 
@odam2k I would say that my space is equivalent to about a 3x3 ft tent, so it's a small space. My humidifier is only a one gallon and so far hasn't used much water. I think it helps that my space is closed off, minus some leakage. As for the dehumidifier, I got one that I can hook up a hose to if it comes to that. My space is next to the HVAC which has an overflow pan, so I can just drain to its drain if I need too. As for monitoring, I look at my graphs a lot, if I see the humidity changes for more than a couple of hours I would investigate. I'm hoping over time I will just learn how often those things will need tending.
 
bobinca said:
@odam2k I would say that my space is equivalent to about a 3x3 ft tent, so it's a small space. My humidifier is only a one gallon and so far hasn't used much water. I think it helps that my space is closed off, minus some leakage. As for the dehumidifier, I got one that I can hook up a hose to if it comes to that. My space is next to the HVAC which has an overflow pan, so I can just drain to its drain if I need too. As for monitoring, I look at my graphs a lot, if I see the humidity changes for more than a couple of hours I would investigate. I'm hoping over time I will just learn how often those things will need tending.
Click to expand...

As a minimum, you could drop a couple wires in the humidifier reservoir and monitor it from the arduino. Once the water level drops below the two wires, they stop conducting... like a switch.
 
@Latitude17 I'm lucky my tap water doesn't have much for deposits. I haven't had to clean a shower head in the 4 years I have lived here. But that is a good idea, I'll just get some distilled water at the grocery store since it doesn't seem to go through much.

My humidity target is 55% right now, thought I might lower it a bit towards the end of flowering. If the arduino detects it is off by more than 4% it will turn on the the appropriate device. I might tighten that up a bit since humidity doesn't change much.

As for temperature, I have it set to 70 at night, 72 when flower is off but veg is on, and 75 when veg and flower are on. I have the arduino turn on the heater or a/c if it is more than 4 degrees away from the target. I would like to tighten that up a bit, but I don't want the a/c to turn on every time the lights go out. So I'll have to code something for that. Maybe I'll step the temperature down more gradually.

When I was using CMH I had lights off during the day, but now with the LED it makes since to have lights off at night since I want it cooler anyway. Because of my allowed 4 degree change in temp, it is possible to see swings down to 66 at night and up to 79 during the day. But overall I don't think that is too bad. When I started in Febuary, I would get swings down to the 40s. The plants were not doing well then. Now that everything is up and running I will start fine tuning.

If humidity is more that 6% above the target and the it is not too humid out side I will let the outside air in. Same with temperature, if it is off by more than 6 degrees and the outside air would help. I consider it a fail safe.
 
The veg temp is up and growing. 20x20 inch is so tiny. I planted two seeds and I'm trying my luck with 4 clones. I've never cloned before so I'm not expecting much, which is why I planted the seeds.

Not much to see with the lid on :)

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I got the SHT31 temp/humid sensor up and running in my flower tent. So far so good, the only thing I don't like is that it had a power led I had to cover up. The readings seem to better match my $10 battery powered digital meter in there (seen in the photo). In the photo the meter read 77F and 53%. The SHT31 read 77F and 54%. The DHT22 read 74F and 62%.

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I had to modify the relay code, currently it turns things on/off based on conditions every 5 minutes. I thought that would be safe so that things would never be turned on an off too quickly. Today it is starting to get a little warm and the AC came on. Turns out the 400 watt AC is a bit powerful for my small set up. The target temp is 75F. When it hit 78 it turned on the AC. After 5 minutes the temp fell to 72, ideally it would have stopped at 75F. I will still check if I should turn something on only once every 5 minutes, but once something is running, it will now check every 30 seconds if it should be turned off.
 
I got my new fan today. I switched from Hydro Crunch 410 CFM 6 in. Centrifugal Inline Duct Fan to AC Infinity CLOUDLINE S6. It took me 2 hours to reduct everything so that I could move the fan to be inside the air tent. I'm not sure if it is the fan or the change to my ducting, but the airflow seems better. The new fan is at 1/2 speed. It is also much quieter in the room under my tent corner of the attic. Before I could hear the fan 10 ft outside of the room. Now I have to stand in the bedroom, directly under the house a/c vent and hold my breath in order to hear it. If someone didn't know what to listen for they might assume it is just some ambient noise from outside.

The old fan had a stated noise rating of 63db. The new fan 32db.

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@bobinca I have very similar issues as you regarding temps. Most nights my heater turns on and off several times. Mine is in the basement so it usually gets colder there first

You can see my set up below. I still have my wemos mini d1 and all components on a bread board. I have been designing a pbc that I can put in an enclosure.
ClimateSt.jpg
GCweek9.jpg
 
Latitude17 said:
Were both fans 6" and the CLOUDLINE just better in your opinion?
Click to expand...

Yeah, both were 6 inch. I bet they move about the same amount of air. But I really like how quieter the new one is. As a plus it was lighter, I think I read 7 lbs vs 10 lbs. And the big plus is that it uses 40 Watts at full power vs 135 watts for the hydro crunch. I'm using the new fan at 4 out 6 for the speed rating. According to some guy to used kill a watt on amazon, that is using 16 watts. I'm pretty happy with that measurement since I run it 24 hours a day.
 
@Dro How much do you let the temp fall before you turn on the heat. Right now I'm experimenting with turning on the heat when it drops 3 degrees below the target temp and it turns off when it hits the target temp.
 

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