-
Happy Birthday ICMag! Been 20 years since Gypsy Nirvana created the forum! We are celebrating with a 4/20 Giveaway and by launching a new Patreon tier called "420club". You can read more here.
-
Important notice: ICMag's T.O.U. has been updated. Please review it here. For your convenience, it is also available in the main forum menu, under 'Quick Links"!
VPD/Humidity controler build low budget (Arduino)
- Thread starter Can of Bliss
- Start date
Can of Bliss
Member
Finely getting around to testing this. Starting with just an empty box. I have the fogger in the plastic bin with some holes cut out. And for dehumidifying I have a itty-bitty 24V blower (that runs on the same power supply as the fogger).
So far, it's still trying to get up to the proper humidity.
So far, it's still trying to get up to the proper humidity.
Attachments
Nice job assembling that!
You won't get up to the right VPD of the room in that cardboard box.
I've been managing VPD for a few months with a raspi and learned you need to make a TROPICAL RAIN FOREST level of humidity. Right now I am humidifying when <.85 VPD.
You could line the box with a trash bag, but you need to have some ventilation for fresh Co2, so the battle is always on to keep humidity up. Once plants are big enough (think leaf mass) they will humidify your room and you may need to start regulating vent independently to bring down humidity.
Good luck, keep us posted!
You won't get up to the right VPD of the room in that cardboard box.
I've been managing VPD for a few months with a raspi and learned you need to make a TROPICAL RAIN FOREST level of humidity. Right now I am humidifying when <.85 VPD.
You could line the box with a trash bag, but you need to have some ventilation for fresh Co2, so the battle is always on to keep humidity up. Once plants are big enough (think leaf mass) they will humidify your room and you may need to start regulating vent independently to bring down humidity.
Good luck, keep us posted!
VintageGreen
Member
I've very recently discovered the humidity battle now that my plant is big enough and just switched over to flowering yesterday. She alone is keeping my 2x2x5.5ft tent at 57% humidity in a 43% humid room. Looking forward to your findings Bliss.
I've got a free raspi 3 coming in with my latest LED driver order. Can you share the code, sensor, and wiring for your raspi VPD manager? Full disclosure: I am a full raspi noob. I know they exist, and that's about it.
Thank you!
newguy41410
Member
okay i think im going to pull the trigger. wondering what differences i would notice going with an arduino clone versus one that isnt?? I think im gonna just buy all the hardware in post #1?
The Meadows
Member
I don't think you'll notice much, if any, difference with a clone vs. a genuine arduino. If you're adventurous enough, you can even build your own arduino.
Buying a genuine arduino will cost a bit more, but you'd be helping the original developer to continue developing.
A cheap clone may have some fit and finish issues but should perform OK. Putting a shield on may require some fiddling with the pins, nothing major. I have a couple of Sainsmart (or something like that) and they've worked for years in continuous duty.
Can of Bliss
Member
Wait, what? If you're talking millibars that's over 95% humidity in most temp ranges. That's way too humid to most peoples standards. Are you using a different pressure unit or am I missing something?
From [The ASCE Standardized Reference Evapotranspiration Equation]1
http://physics.stackexchange.com/qu...deficit-from-temperature-and-relative-humidit
Given T is temperature in degrees Celsius, and RH is relative humidity:
- Saturation Vapor Pressure (es) = 0.6108 * exp(17.27 * T / (T + 237.3))
- Actual Vapor Pressure (ea) = RH / 100 * es
- Vapor Pressure Deficit = ea - es
Can of Bliss
Member
Right, but what did you mean by "<.85 VPD" ?
Can of Bliss
Member
Cool, thanks, I'll have to look at that code. Looks like a great starting point for some dope grow automation.
What programing languages do you work in? Feel free to contribute to the github
If you choose to implement the formula to control a humidifier, the equation will calculate a value that corresponds to the the chart at the same temp/humid.
If you are controlling humidity, then the sweet spot is to stay between 5.0>X>1.2 which, 8.5 is the midpoint.
My apologies. The magnitude is different on my version of the equation, which i did not code, so my RasPi says .85 instead of 8.5
VintageGreen
Member
Basically the same formula in my old post. Basically staying at 8.5 for me is turn on / off humidifier at outlying values (5 and 12). This is what I did to prevent humidifier power flapping (turning on / off humidifier every min).
newguy41410
Member
can you recommend what type of wire i shoudl get? im about to order the hardware but want to makke sure i got all the wires and any types of connectors you think will definitelly come in handy and save me trips from the stores. i hate when i order a bunch of stuff for a project and then im all excited to start only to find i need a specific small common item that i just dont have in my house lol
Can of Bliss
Member
What programing languages do you work in? Feel free to contribute to the github
so my RasPi says .85 instead of 8.5
Ahhh, that make way more sense.
What programing languages do you work in? Feel free to contribute to the github
I'm pretty much illiterate, I just bought a book on arduino programming so I can kinda fake it. But I like messing around with stuff I don't quite understand. Please share the link (maybe you have, I'll have to double check once I'm not writing this post).
Can of Bliss
Member
A lot comes down to personal preference. I use a lot of these jumpers
https://www.amazon.com/Elegoo-120pc...coding=UTF8&psc=1&refRID=G9JX5JE3KAV49KHM32AR
they are good for testing stuff, but if you're trying to make something permanent soldering wires is always best.
Having a few LED's and resistors around may prove useful too.
Remember, that relay board I linked to is rated for 120v 10 amps, so you should find something bigger if you're running something that pulls more that 1.2Kw (I like to keep things oversized, so wouldn't use if for more than about 900w).
newguy41410
Member
damn,i just bought the relay board on amazon before reading this. The heater i plan to use for it is a 1500 watt. What do you suggest i do?
EDIT: NEVERMIND. dont need to hook up a heater to this system, it adjusts humidity in relation to temperature, correct?
Last edited:
Can of Bliss
Member
It's possible to run a larger load off two relays at the same time. It's not exactly "safe" and will fail sooner than the proper rated relay, but sometimes it's a useful trick.
That's right, but if you want to use a dehumidifier, those can take a lot of juice. An exhaust fan it what I was planning for my own setup.
newguy41410
Member
hey guys just got my gear!
I hooked it up for the first time and tried testing out my DHT22 sensor. Im not using the VPD code just a simple adafruit code that reads temperature and humidity and displays it in serial monitor. But for some reason i keep getting "nan" readings most the time. Is this because I don't have a resistor between the positive and signal wire??
Is my sensor defective? Or does it just need a resistor??
I hooked it up for the first time and tried testing out my DHT22 sensor. Im not using the VPD code just a simple adafruit code that reads temperature and humidity and displays it in serial monitor. But for some reason i keep getting "nan" readings most the time. Is this because I don't have a resistor between the positive and signal wire??
Is my sensor defective? Or does it just need a resistor??
