Hello fellow Arduino fans,
I'm new to this forum and wanted to post my currently ongoing project.
I'm not a native english speaker, if you find errors keep them, I ain't gonna collect them.
Prologue
Or: why I started this project...
I live in Peru in the outskirts of the capital city of Lima and as it is basically a desert here, I have a problem: I travel frequently and any plants left without watering die within days with the exception of some cactus and other highly dry resistant plants. We have a summer where it is "hot" (26° to 30°C) and completely dry with burning sun everyday. Temperature isn't the main issue, the nearby ocean is cooling but the suns intensity is higher than one might be accustomed from Europe or United States.
After having some trouble of bringing my pot-plants to friends, having the bigger plants watered by neighbours, several plants dying... I decided, hey, you're an IT guy or at least used to be one (studied "Informatik" at the KIT (Karlsruhe Germany) there ought to be a technical solution to this problem.
The Idea
I wanted to somehow automate watering my plants. First in a specially build "rack" or something, once I have it working maybe adapt and create a second system for the other pots, lets see when we get there. Also I'll maybe create a bigger watering system for a big garden / small plantation at the vacation residence I'm about to buy but that is future too. For now, I'll build a 3 story rack with some nice plants for my "balcony" (it's build like a balcony but is first floor, dunno how to call it, not really a terrace)
I first thought about using my Raspberry Pi that I had laying around but Arduino has analog inputs (so that I don't need analog digital converter for everything), Arduino has nice shields and uses less energy. As I'd like to use a cellphone powerbank in conjunction with a small solar panel as power supply, the lower energy consumption would make it much easier.
So Arduino it is. Got hold of an "Arduino Upgraded Learning Kit" my brother didn't need anymore.
I have no Energy or Water supply out there so I need tanks. As my first project doesn't need to be able to work to many days without intervention I guess I'll start with two big 7L water bottles as tanks --> 14L I can upgrade later. First get the valves and sensors working. I'd like to just mount the Bottles high and let gravity do the rest, if that isn't enough i might someday switch to a bigger tank and a pump.
I'll keep this thread mainly on the Arduino and its inputs and outputs so no lengthy discussions of which plant needs how much water, which pipe to use etc.
Things I definitively want / need:
- Valves
I need to turn water flow on and of - Soil humidity sensors
I need to know when to water the plants
Optional stuff:
- Air humidity and temperature sensor
Would be nice to check for that once we're at it. More data = more good. - Water level sensor for tanks
Of course, knowing that your automated garden is running out of water when you have hooked it up to such small tanks could be quite important... - Some wireless communication
I would love to transfer the data to my PC without having to go to the arduino or to put up some cables. WiFi is quite Energy hungry, so maybe bluetooth, see below - ePaper Display
So that the Arduino can directly display its sensor readings and some other little things while doing its work
The current Status (updates pending)
As said above, I have an Arduino UNO R3 with some sensors, cables etc. I have some (pen and paper) sketches of the whole thing (might upload them later).
ATM I'm deciding on some hardware stuff:
I want 3 stories of plants with one valve each and ideally 2 soil humidity sensors each. That would already be 6 (analog) Sensors and 3 outputs even though I could combine the two sensors of each story into one input. The valves will use to much energy so they will be connected via relays and draw energy directly from the Powerbank. The powerbank should be able to provide more than enough and as those solenoid valves only need power when opened, those 5 minutes a day the solar should absolutely be able to provide enough energy for them over the day.
But that means that for the valves, aside of cables I need:
- relays
Possibly one of those shields with 4 relays for motor control... - DC/DC converter
depending on the voltage of the solenoid valve... many are 12 or even 24V - the valve itself
good compromise between cheap and reliable...
For the soil humidity sensors I thought about something like:
Taidacent capacitive soil moisture sensor from alibaba.com
There are much more expensive options that I think are overkill. I would coat the electronics part above with clear nail varnish - I did that already several times to insulate electronics from the elements... I guess capacitive is good because the part in touch with the soil has no exposed metal so it won't erode.
For the optional stuff from above I'm currently looking into how many I/O pins I have left, what products are on the market and which ones to possibly buy.
The water level sensors for the tanks would be really good but it is kinda hard to get a good solution. Here I have to decide first on the technology I want to use. I could use pressure sensors as pressure when working with only gravity and no pumps is directly equivalent to water level, I could mount IR sensors inside the tanks but the cheaper ones aren't water resistant... or use capacitive measurement. I won't use swimmers as those tend to get "bulky" and are basically only good if you want to know "full or not?" but not for exact level.
If you have any suggestions either on hardware I could / might / should by or on technical details etc. please post below. I will update this post from time to time but don't expect this project to be done in days, I'm working full time and have a family. I expect the project to go on for at least 3 months. There are some sketches already that I will scan these days and upload as soon as I consider them "more or less finished".
Sketches, Fotos etc. to be uploaded.