Arduino experiments - Datalogger for the grow room

bellcore

Well-Known Member
Yep :) That'll come down to how loud they are.
Do you know if they come with a battery?
An indirect seller said his don't come with a battery, but I couldn't find it mentioned in the actual Tindie pages - just what type of battery they use.

Edit: I messaged the Tindie seller and he said they don't come with batteries.

How are those Chirps working out? I think you can adjust the sensitivity, is that correct?
 

GreenLogician

Well-Known Member
How are those Chirps working out? I think you can adjust the sensitivity, is that correct?
They are awesome! I love them.
Yes you can adjust the sensitivity. There's only one button, and you press it when the probe (base of the device) is at the moisture you want the alarm to go off next time.

So to set the sensitivity, put it in the soil, then wait until it's the perfect time to water, and press the button (and then water after). Then it will always go off at that moisture.


They come with exposed circuitry, and a warning to try to minimize how wet that gets.
Fortunately, they also come in a plastic sleeve for packaging. Keep that, it's great to slide over the top half of the device while watering. (If you lose one, you can cut the base off of a toothpaste tube or small shampoo bottle and wash it out.)

p.s. One of my four arrived faulty, but it was unquestioningly replaced, with the seller covering the sending cost.
 
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hey in the intro you were talking about the 0-10v dimming of the hlg drivers from the arduino do u have a schematic how to do this? the programming of arduinos is nog problem always those dem eletronics that are needed :p
 

InTheValley

Well-Known Member
Plant Temperature camera = IR Temperature sensor

A Plant Temperature (PT) camera is used to measure the leaf temperature which, along with the ambient temperature and humidity, can then be used to determine the Vapour Pressure Deficit (VPD). When used in combination with the plant temperature (PT) this is a measure which shows how easy it is for the plants to transpire. How to use these measurements is explained a bit later.

The PT camera is basically simply an IR temperature sensor with an I2C interface. I broke out the center of the glass in a dummy security camera and installed the IR temp sensor through it. Was quite a good fit and with some extra padding around the sensor it fit rally snugly. I hooked up the sensor to an USB cable and this plugs into the Arduino.

You can see the sensor peeking out through the hole in the middle:
View attachment 3570528

The sensor mounted to the front bit of the dummy camera housing and the simple connection i set up to the USB cable:
View attachment 3570529

The PT camera in action monitoring the ladies:
View attachment 3570530

How to calculate the VPD?
The VPD is the difference between the saturation vapor pressure at the plant temperature and the measured ambient vapor pressure. I’m using this formula:
VPD = 0,6108*EXP((17,27*PT)/(PT+237,3)) - 0,6108*EXP((17,27*AT)/(AT+237,3)))*RH/100

The VPD calculation is based on the following parameters:
- Plant temperature (PT in degrees Celsius)
- Ambient temperature (AT in degrees Celsius)
- Relative Humidity (RH percentage)

In general for most plants the VPD should be slightly below 1kPa, but I also read that for cannabis it should be between 1.0 and 1.5kPa. When the VPD is too high the plants will be transpiring too much so you should either lower the temperature (dim the lights) or raise the humidity. When the VPD is too low, the plants could grow more if their transpiration was higher and if very low the plants might get wet becaue they can;t lose their moisture through transpiration.

View attachment 3570527

When a plant is in vegetative phase it can still adapt to it’s surroundings. So the VPD is not so much an issue then. You shouldn’t change the climate based on that. Also when the plants are smaller you will usually measure not just the plants but also the walls or floor behind the plants. When the grow room is nicely filled with plants which are flowering then the VPD becomes more interesting.

I noticed the VPD has some sort of cycle where it starts off high when the “day’ starts, then it drops during the “day” and before the lights go off it goes up again. The VPD is the orange line at the bottom of this image:
View attachment 3570531

I’m still trying to figure out if this actually means the plants could use more light in the middle of the day or that this is just the result of something else. My idea was to dim the lights on a curve similar to how more sunlight reaches the plants at noon and less in the morning and evening. Overall the plants would get the same amount of light energy, but then perhaps they can use it more efficiently this way.

Dimlux sells a controller that protects the plants from overheating based on the same VPD principle. Although they only use it as a protection when the system is unable to keep the climate within the proper range.

The plants should always be slightly colder than the ambient temperature because the plants are cooling themselves by transpiring water. The Dimlux controller will dim or switch off the lights when the PT goes above the air temperature or when the VPD goes too high. When the plants are no longer transpiring something is seriously wrong. The plants will then have closed their stomata to protect themselves against drying out. That means no more photosynthesis is going on either. That’s damaging to the plants and a massive waste of energy in lighting. You can see the same occur with plants outside when they receive too much sun and heat.
Great findings Bud. I stumbled on your thread here, and tend to read it all, but wanted to reply to this post since im here. Ive heard the plants only need 6 hours of strong daylight a day. I just talked to someone about my light schedule being 16-8, were i would like to dim 50% first 4 hours, 95% for 8 hours, 4 hours 50% dimmed. just need a dimmer.

just funny that i stumbled onto this today,

Good stuff, this is very interesting to me.
 

boertje

Member
@ Wietefras

I read your post on the lepton flir. It completely tempered my enthusiasm for my recent purchase. I just ordered the radiometric version a couple of days ago with the intention to log some data from it, or perhaps even use it as a sensor. Do you also have the radiometric version? The other versions seems to be useless for our purposes for they render no temperature reading data. Better not being a waste of money
 

ttystikk

Well-Known Member
Great findings Bud. I stumbled on your thread here, and tend to read it all, but wanted to reply to this post since im here. Ive heard the plants only need 6 hours of strong daylight a day. I just talked to someone about my light schedule being 16-8, were i would like to dim 50% first 4 hours, 95% for 8 hours, 4 hours 50% dimmed. just need a dimmer.

just funny that i stumbled onto this today,

Good stuff, this is very interesting to me.
There's a guy on here who's been running 8 on and 16 off for years now, no dimming. Works great for him.
 

Philip-O

Well-Known Member
This is great. How did you like the clip on supports? Do you still use them? I was looking for something like this to hold a trellis on a gorrilla tent.



Thanks :)

The code isn't available, but for these things it's usually just a matter of using a bit of example code. For pretty much all sensors you can find example code from Adafruit, Sparkfun or something like that.

The basic datalogger code you can also find examples, but everybody likes to do those things their own way. For now my code is still much a work in progress although the basic data logger has been running for quite a while now and I rarely change anything there.

The 3D Printer I bought is the Ultimaker 2: https://ultimaker.com/en/products/ultimaker-2.

I designed a fan duct and I needed to split that in two to get it to print:
View attachment 3570554

Also made some supports that clip onto the tent poles for fixing a scrogg net:
View attachment 3570556 View attachment 3570555

A funnel for transferring the ground up weed from the grinder into the holder for the Plenty vaporizer (the white bit visible in between the grinder and holder):
View attachment 3570557

A sturdy ratched rope holder (downloaded from Thingiverse)
View attachment 3570559
 

wietefras

Well-Known Member
This is great. How did you like the clip on supports? Do you still use them? I was looking for something like this to hold a trellis on a gorrilla tent.
They work great, I'm still using those original support clips from the picture for a scrog net in my current test grow.

I do tie a bit of the rope over the bit where the stick rests in the support clip.
 

Philip-O

Well-Known Member
They work great, I'm still using those original support clips from the picture for a scrog net in my current test grow.

I do tie a bit of the rope over the bit where the stick rests in the support clip.
Could you share the part design files so I can get it 3d printed (adjusting for width or as necessary), or give me some pointers to find designs? I do not know anything about cad designing and 3d printing, but it is something I´m much interested in learning. Thanks!
 

wietefras

Well-Known Member
Could you share the part design files so I can get it 3d printed (adjusting for width or as necessary), or give me some pointers to find designs? I do not know anything about cad designing and 3d printing, but it is something I´m much interested in learning. Thanks!
I made this in FreeCAD. I have attached the file, but I found it wasn't one of the easiest programs to modify the design afterwards.

It's pretty straightforward design though. A couple of cubes and cylinders and your there :)

I use OpenSCAD now, but that's more for people who are used to computer programming I guess.
 

Attachments

Philip-O

Well-Known Member
I made this in FreeCAD. I have attached the file, but I found it wasn't one of the easiest programs to modify the design afterwards.

It's pretty straightforward design though. A couple of cubes and cylinders and your there :)

I use OpenSCAD now, but that's more for people who are used to computer programming I guess.
Thank you very much man. I´ll get to play a bit with freecad, to try and change the outside part from a rectangular slot to a round piece (I use pvc pipes for my trellises).

I actually got to your post looking into the plenty vaporizer (since you were showing your funnel). I´ve just ordered one, but it does not hurt to ask how do you like it?
 

wietefras

Well-Known Member
Thank you very much man. I´ll get to play a bit with freecad, to try and change the outside part from a rectangular slot to a round piece (I use pvc pipes for my trellises).
It's just a case of adding cylinders and subtracting smaller cylinders.

I actually got to your post looking into the plenty vaporizer (since you were showing your funnel). I´ve just ordered one, but it does not hurt to ask how do you like it?
Yeah I like it. Great vapor and good taste. I also have a Firefly 2 for convenience when I don't want to be tight down to an outlet, but the cable for the Plenty is long enough. I think the Plenty is a better vape than the Firefly 2, but the firefly 2 is more convenient since it's small and portable. But then it's a bit too small for more than one person to use.
 

Philip-O

Well-Known Member
It's just a case of adding cylinders and subtracting smaller cylinders.


Yeah I like it. Great vapor and good taste. I also have a Firefly 2 for convenience when I don't want to be tight down to an outlet, but the cable for the Plenty is long enough. I think the Plenty is a better vape than the Firefly 2, but the firefly 2 is more convenient since it's small and portable. But then it's a bit too small for more than one person to use.
https://www.instagram.com/p/Bc97k-FHANM/

Good idea for a 3D project? Have you already done this ;) ?
 

tomate

Well-Known Member
I’m still trying to figure out if this actually means the plants could use more light in the middle of the day or that this is just the result of something else. My idea was to dim the lights on a curve similar to how more sunlight reaches the plants at noon and less in the morning and evening. Overall the plants would get the same amount of light energy, but then perhaps they can use it more efficiently this way.
Could it be a sign of saturation? Plant has reached its max DLI and is starting to close the stomata which results in less transpiration which leads to a lower RH and higher temps?
 

wietefras

Well-Known Member
Could it be a sign of saturation? Plant has reached its max DLI and is starting to close the stomata which results in less transpiration which leads to a lower RH and higher temps?
Perhaps. Though they get a much higher DLI during the vegetative phase when they receive 18 hours of light then when they get only 12 hours of light. Yet I see the same curve when they receive a DLI of say 45mol/day versus when it's 30mol/day. Apart from that the curve gets compressed to s shorter time frame of course.
 

tomate

Well-Known Member
Yet I see the same curve when they receive a DLI of say 45mol/day versus when it's 30mol/day. Apart from that the curve gets compressed to s shorter time frame of course.
So the PPFD is always at the same level, regardless of the lighting cycle? 45 mol/d @ 18/6 and 30 mol/d @ 12/12?
Do you have a plot of a 18/6 lighting cycle?
 
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