Back to wateringduino!!

Well... The Summer is coming, we're almost at Spring time and I bought a solenoid and finally got the wateringduino on the field. This year I'll have fantastic strawberries I can assure!
I made some changes to the project, and I'm still adapting it to the needs I have, so, let's see:

- Circuit 1; Watering the strawberries based on data collected by the probe. I found out that it works fine but there's an adjustment needed to guarantee that the moist level doesn't change so drastically during daytime with the temperature change.
- Circuit 2; I intend to improve and change this circuit to water the raspberries and blueberries during daytime within the most warm hours in two small periods of time (4 minutes only), once before 12:00 and another afterwards, to keep the roots slightly wet but not too wet. A probe will not be used, I'll use the RTC instead to do the job.
- Circuit 3; Is to be changed, not using probes, using the RTC instead, as in circuit 2 but in this case watering the trees daily for 20 minutes, probably a couple hours before sunrise.

I leave some graphs I got from the SD logger that wateringduino has implemented.
The first one (on the left) is a temperature graph of an underground probe, about 0.5 meter beneath soil surface.

The second one (on the right side) is the moist values the system got, and as you can see it needs some adjustment because the moist values don't change that much during daytime, so, what's happening is that conductivity changes with the heat, and as the strawberry "vase" is hanged at about 1 meter height, it get's warmer with the sun rays during daytime, hence, the voltage gets higher within warmer conditions. The corrective formula (there are also corrective tables, but the application of an equation is easier to do) is this one:

I haven't decided yet if I'm going to use it, after all it's extra hard-work as a tradeoff of cleaner data, so... Nevertheless it means that the electric conductivity at 25 Celsius is equal to the obtained electric conductivity multiplied by an exponential factor which has the soil temperature within it, aimed to balance the data.
The orange spikes concern the moments that the system starts watering.
As you can see the system is working fine and I have now nicely wet strawberries! Cheers!

Soil moist monitor/manager and logger!

The 'what if' problem...
This project started with a LED, a moist probe and an arduino. Then I thought "what if" adding another probe? After that, "what if" adding an SD shield to log the values? 

When done, "what if"... You understand what I mean, I'm sure. 

So this ended up in a complex system as described:

- 3 Moisture probes, (max) which can be grounded (with a jumper or so) this way you can use from 1 to 3 probes as you need them. (as the one you can see in the picture)

- 3 Solenoid outputs, which will set up the watering of each probe plant (solenoid 1 will open if soil moisture probe 1 alerts for a thirsty plant.)

- 1 Digital thermometer, to log temperature.

- 1 LED.

- 1 Press button.

- 1 RTC (pointless to have a logger without date/time).

- 1 SD shield and card to retain system data.

- 1 arduino board or a DIY arduino board.

My self made board design can be viewed in the picture:

 Now, the most important, how does all this works?

You use as many probes as you want, with a maximum of 3, and connect all the devices, the system boots up, and the led will give you information about the moist:

- 2 blinks - too wet... :(

- 1 blink - GREAT! 

- Fading - too dry.

In the last state, the output pin for the solenoid will turn HIGH and open a TIP120 or a relay circuit (not done yet) to open the solenoid and then water the plant.

The time of each reading is 15 minutes, which changes to 2 minutes when a plant is dry and the solenoid opens, to assure a more accurate watering.

There is also a press button for knowing the water needs at any time, once pressed, 1 second or so later the LED gives you the information needed, not written to console nor SD card.

The logger has a format like this:

Initializing SD card... Warming up!! Starting!!!
Date    Time    Temperature    Pb1    Pb2    Pb3    V1    V2    V3    Ws1    Ws2    Ws3
2013-07-01    20:41:59    24.50    81.64    76.27    76.56     4.08     3.81     3.83    0    0    0   
 

It can be worked out in a spreadsheet or any program that deals with this kind of data, (separated by tabs). A file is created EACH month with a name like "201306.csv" which stands for the year and the month. V1, 2 and 3 are the voltage values read by arduino and Ws1, 2 and 3 are the watering status, a boolean value which is 0 or 1 depending of the watering status, 1 when watering.

I hope You enjoy this, (as I wrote, I have many flavors of this, with several combinations) now go monitor your plants, mine have never been so pretty since I started this, and though I don't have the solenoids working, the LED indications are usefull enough to get them awesome!

The code.The prototype configuration on the picture:
Used this SD library and this RTC library.