Arduino experiments - Datalogger for the grow room

Great stuff! you just opened pandora's box for me.

The tube with the ceramic tip is filled with water completely, even submerging the sensor? which would mean you sealed the housing between the sensor and the electronics? Does the water in the tube go above the actual soil line? I've never worked with blumats so my conceptual understanding is limited.

Did you tie in your tensiometers reading to a relay to switch on the watering pump? I would like to do something like this in multi feed coco system, very much how its done in huge greenhouses, but am unsure as to get around some potential issues I see. When you start watering, the tensiometers readings probably spike before the pots get enough water/runoff. What arduino code, hardware, and irrigation equipment do you use to get around this problem? Timer delays, sensory input, or what, just not sure here.

Is your raspberry PI connected to any sensors or is just used for data logging and connectivity? I still need to figure out how much RAM these sensor take up and what limitation are for the Arduino, all these definitions are new to me so I feel like I'm kinda just floating around right now still looking for some footing.

can you talk more about your DWC setup and how you made it IoT friendly?

I can't wait to see more, wish I spoke german, but your other forum has answered a few questions that have already come up for me.

Very nice work!

I too would appreciate more of an explanation on the DIY tensiometers and how you have everything hooked up with respect to logging and water control like @mduke said above.

So a while ago I was working on building my a FLIR LeptonArduino base Thermal imager. I indicated that due to the amount of time and effort needed for that, I better just buy a FLIR One. So, I broke down and bought the FLIR one

I have to say these things are pretty cool. Slightly more difficult to use than I imagined, but it's mostly just point-and-shoot. It's a dongle that attaches to a smartphone and can then use it's CPU and screen. So the costs are relatively low ($250).

Plants in a 100cmx100cm grow tent under eight 50W CXB3070 Cree COBs:


A single led and i's cooler (the hot strip beneath is the zipper):



Checking out the COBs:




Weird to see how the Kapton tape is trapping the heat. Or perhaps it's interfering with the thermal imager.

It can also do time lapse thermal imaging.

What scared me a little is the fact that I can actually see where I walked. There are clear footsteps visible on the floor. I can only imagine how bright an exhaust for a grow room would look on one of these things.

Well actually I could go measure it, but I only have this small tent running at the moment. Still, I'm going to check whether some thermal signature is visible from the outside even from a mall grow like that.

wietefras said:

So a while ago I was working on building my a FLIR LeptonArduino base Thermal imager. I indicated that due to the amount of time and effort needed for that, I better just buy a FLIR One. So, I broke down and bought the FLIR one

I have to say these things are pretty cool. Slightly more difficult to use than I imagined, but it's mostly just point-and-shoot. It's a dongle that attaches to a smartphone and can then use it's CPU and screen. So the costs are relatively low ($250).

Plants in a 100cmx100cm grow tent under eight 50W CXB3070 Cree COBs:
View attachment 3600947

A single led and i's cooler (the hot strip beneath is the zipper):
View attachment 3600948


Checking out the COBs:
View attachment 3600949

View attachment 3600950

Weird to see how the Kapton tape is trapping the heat. Or perhaps it's interfering with the thermal imager.

It can also do time lapse thermal imaging.

What scared me a little is the fact that I can actually see where I walked. There are clear footsteps visible on the floor. I can only imagine how bright an exhaust for a grow room would look on one of these things.

Well actually I could go measure it, but I only have this small tent running at the moment. Still, I'm going to check whether some thermal signature is visible from the outside even from a mall grow like that.

Click to expand...

Cool!

Wow I gues I missed a lot of replies. Sorr about that.

@Purpsmagurps, I started out small too, but then my inner geek took over

@sethimus and @DISTRESS0R I like the Arduino because it's single threaded and easy to predict. It's also especially equipped for reading these sensors. I use a Raspberry pi as the webserver, but technically any old fileserver or mediaplayer could function as a webserver for somthing like this.

I also bought an Arduino Yun shield. That's a combination of a Raspberry Pi like computer which you click on top of the Arduino as a shield. I think that's easier and cheaper than a Raspberry pi.

@TommyDuhCat, Cool. I started out trying to build a telemetry device for kart racing. Back then that was a lot of work, but nowadays you can buy ready to use sensors for just about anything.

@bggrass, RasPi is a lot more expensive than Arduino. Just the shield to be able to attach sensors to the RasPi costs more than an Arduino. if you want to get into something like this, try AliExpress.com. You can buy a tiny Arduino (Pro Mini) for less than $1.50.

I'm a software engineer/developer as my profession, so coding is luckily not an issue.

@mduke, The tube is filled completely, but the sensor sits on top of the tube. It's not actually in the water. Well the plastic tip might be, but not the electronics. You could also use a rubber tube. I use Blumat watering sensor tubes. These come with thin rubber driplines which fit perfectly on the pressure sensor..

The whole thing is sealed, so the water cannot get out of the tube and therefore not into the electronics either. Although I wouldn't try holding the thing upside down. I guess the air might escape out of the pressure sensor and let the water in.

My original plan was to use the tensiometers as an indicator for watering the plants, but there were some issues with that since I was using soil. In rockwool or coco systems it would probably work better, but from what I understood tensimoters don't always work well with those substrates. Besides you can just flush it till it drains. Much easier to detect that than measuring substrate moisture levels.

What I did was log the tensiometers over time. Then I'd water the plants and see how far the tensio pressures went down and then check the next day where it was back up to then. I used that as an indication of whether to give them more or less water for the next day.

I never got around to automating this though. I switched to DWC hydro instead. Then it's just a matter of topping off a bucket of water.

The Raspberry pi is only used as a database and webserver. It's much easier and cheaper to use Arduino's to connect to the sensors.

Guy I know uses Arduino's with 2.4Ghz radio's. The Arduino's read the sensors and transmit wirelessly to the Raspberry pi. I use a network cable to get the data to the RaspPi instead.

Didn't do a whole lot to the DWC yet. I only have a thermometer in the water really. In the tent itself I have a lot of sensors which are connected to a single Arduino.

I do want to start logging the pH and EC and DO (dissolve oxygen), but I have so many other things to do first that I haven't gotten around to that.

I also want to bring back the system that can mix the water for me to the right pH and EC levels. I had that working for pH, but I needed the parts and now I have to do it manually again.

Some other Arduino's hang around doing things like topping off the water in the buckets and I ordered parts to measure how much water it supplies to the plants over time. That would show how much they drink at every time of the day or night.

Another one is controlling the fan speed. I guess I should go ahead and still describe those systems here as well.

I've been meaning to hook everything up together. For instance show the fan controller data in the data logger, but I haven't gotten around to that.

@benjaminDANKlin, Hooking up the tensiometer is quite simple. It sends out an analog signal. The Arduino measures the voltages and the datasheet provides a formula to convert that voltage to a tensio value.

Using a tensiometer for watering your plants is a challenge though. Like i said, I didn't get around to working that out.

ttystikk said:

Cool!

Click to expand...

Or hot! I can see both now

I actually switched to an omega chip with wifi shield 5 soil hygrometers, dht22, camera

wietefras said:

Or hot! I can see both now

Click to expand...

Wish I could borrow your toy for looking at my water cooling system.

Wow, that is all so cool!
If the kitchen scales calibration issue could be solved, that would make a great product to commercialize.
It could give me a little alarm or notification when it is time to water. I'd definitely buy one

@Purpsmagurps, Yeah, new alternatives are coming out all the time.

What kind of hygrometers are you using? Resistive ones? Or capacative or something else?

@ttystikk, Yeah, I'd be very interested too. Still need to start working on own my water cooling project. For now I only have parts laying around.

@GreenLogician, The plant is also growing and it's difficult if not impossible to estimate it's weight. so after a while you can't really use scales anymore.

Unless you work with a substrate that allows you to flush it to capacity. Like rockwool or coco. Professional glasshouse growers use those things too. When you flood those substrates the scales can tell when the substrate is saturated and it starts to drain. That gives you a benchmark weight. That way you can actually measure the weight of the plants.

I also intended the scales to be used to measure plant growth rather than soil moisture.

If you want a simple alarm telling you wen to water the plants, perhaps the Chirp is an option?
https://www.tindie.com/products/miceuz/chirp-plant-watering-alarm/

You stick it in the soil and it will chirp when it feels the plants need water. Although I personally wouldn't like devices making sound and attracting attention to my grow area.

A digital tensiometer works well too. Like the Blumat Digital. It gives you a reading of how much suction is needed to extract water from the soil. It gives a pretty accurate value of how easy it is for the plants to drink. Although it is a bit localized, so you need to make sure you water evenly.

The soil should have a tensio value of around 80kPa. So you can aim for that. Works pretty well really

Of course when you connect those to a datalogger it gives you even more insight in what is happening inside the pots

@wietefras I love my water cooling system, it's so efficient. Only 4 Tons of chilling to cool a 25kW op.

Moving forward, I'm installing a water chiller with hot gas recovery, effectively a dual circuit heat pump that removes heat from the cold circuit (to make and keep it cool, lol) and puts that heat into the hot side circuit, which can be used for anything you can think of using heat for. This could include home heating, domestic hot water, dehumidification in grow rooms, thawing the driveway so I never need to shovel it again, heating my garage, hot tub, etc.

Back up; dehumidification? Yep; the water cooled air handler cold the air and squeezes moisture out of it, and this hot water will drive hot water baseboard heat to add heat to the room to keep it warm at night when the air handlers are running. It's MY heat; I've paid for it once and I've even paid to remove it from my grow. Why not use it to its full potential?

I promise, you'll enjoy the benefits just as I do.

I'll help you with your water cooling system if you'll help me use arduino to control my various systems here.

Exactly, reusing the heat from the leds is what I want as well. Was also looking at a heat pump and hope it can help with dehumidification. Although my grow is nowhere near the size of yours

My Arduino systems are really more a hobby. It's to show what you can do with some relatively cheap parts and a free weekend. They are not intended for commercial use. I usually just make sure it works (mostly) and move on to something else.

There are more complete open source Arduino and/or Raspberry pi based grow systems though. Maybe you can use those? Although the problem with those usually is that they disappear after a few years.

It's really amazing how many of the links I collected over the last 2 years no longer work. These still seem to show something though:
https://www.rollitup.org/t/my-arduino-hydroponics-controller-hyrdobot.550873/
https://www.rollitup.org/t/arduino-controlled-grow-and-pc-program-work-in-progress.520965/
http://gardenbot.org/howTo/
http://arduinogrc.blogspot.nl/

Or google for new initiatives.

Or there build a Farmbot
https://farmbot.io/

wietefras said:

Exactly, reusing the heat from the leds is what I want as well. Was also looking at a heat pump and hope it can help with dehumidification. Although my grow is nowhere near the size of yours

My Arduino systems are really more a hobby. It's to show what you can do with some relatively cheap parts and a free weekend. They are not intended for commercial use. I usually just make sure it works (mostly) and move on to something else.

There are more complete open source Arduino and/or Raspberry pi based grow systems though. Maybe you can use those? Although the problem with those usually is that they disappear after a few years.

It's really amazing how many of the links I collected over the last 2 years no longer work. These still seem to show something though:
https://www.rollitup.org/t/my-arduino-hydroponics-controller-hyrdobot.550873/
https://www.rollitup.org/t/arduino-controlled-grow-and-pc-program-work-in-progress.520965/
http://gardenbot.org/howTo/
http://arduinogrc.blogspot.nl/

Or google for new initiatives.

Or there build a Farmbot
https://farmbot.io/

Click to expand...

The biggest problem with using heat from LEDs is that you'll need a lot of them to get any useful heat to play with.

On the other hand, since my system is small, I don't need a lot of heat to get things up to temperature.

But indeed it doesn't allow for the more sophisticated things that you use

Thanks heaps, I just ordered 4 Chirps!
I'm one year into my computer science degree, and you are like a professor

Hope you checked the description so you have an idea if they would fit your situation. Like I said, they will make a sound when the plant is "thirsty".

But then you could just water the plants normally and only if you forget or don't water enough you'll hear the ladies complain

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.

I use an Arduino to control most aspects of my grow also.

LOG said:

RTC has set the system time
Hydroponic Control Program 3.3 Started at 0:33:57 7/11/2015
Grow Tent Humidity: 36 % Grow Tent Temp: 86 *F Heat Index is: 84.67
Room Humidity: 34 % Room Temp.: 77 *F Nutrient Temp: 66 *F
Fan Off.
Nutrient Peltier Off.
Light ON
Time is: 0:33:58
Grow Tent Humidity: 36 % Grow Tent Temp: 86 *F Heat Index is: 84.67
Room Humidity: 35 % Room Temp.: 75 *F Nutrient Temp: 66 *F
Fan Off.
Nutrient Peltier Off.
Light ON
Time is: 0:46:00
Grow Tent Humidity: 37 % Grow Tent Temp: 84 *F Heat Index is: 82.85
Room Humidity: 35 % Room Temp.: 75 *F Nutrient Temp: 65 *F
Fan Off.
Nutrient Peltier Off.
Light ON
Time is: 1:00:01
Grow Tent Humidity: 39 % Grow Tent Temp: 86 *F Heat Index is: 85.24
Room Humidity: 35 % Room Temp.: 77 *F Nutrient Temp: 65 *F
Fan Off.
Nutrient Peltier Off.
Light ON
Time is: 1:15:03 "

Click to expand...

@GreenLogician , Those batteries are pretty cheap.

Don't have much time lately to do much with Arduino's, but I did get around to update the "Waterinator" for my new grow.

Before I had the sensor attached to a netpot in a empty spot in the DWC system:


Now I have 2 boxes connected with a pipe (and no empty slot).



So I adapted the sensor to fit on the T splitter:


This system tops up the system every 15 minutes by switching on the 240V outlet to run the pump until the water level sensor switches off.

The open box shows the relay in the top left, Arduino Pro Mini in the top right and a 5V power supply in the bottom. All modules and components are soldered to a proto board. The sensor is to the right attached to the black disk that I use to close off the T-splitter. The 3D printed bolt and screw allow for adjustment of the water level

Unfortunately I'm still waiting for tubes from China which I want to use to connect a flow meter to measure the amount of water that is fed into the system. When I get that I will also 3D print a new housing so I can better separate the 240V and 5V sections and also add a tiny OLED display showing how much water has gone into system over the last hour and last 24 hours.