The DIY Smart Garden System

I’m going to take you on a tour of Do It Yourself Smart Gardening

My name is Cory, I’m a Technical Craftsman specializing in creative problem solving within electronics and software engineering.  Professionally, I’ve worked as an electronics engineer, a plastics fabricator, software engineer, an industrial laser technician, and, of course, a coffee barista.  I’ve spent the last several years working on a Smart Garden System project I named, hydroMazing.  I’m sharing my work with you because I would like to empower everyone who is interested in a “Smart” approach to gardening.

What we’ve covered so far:cropped-hydromazing_smart_garden_system

 

Are you interested in following me on this journey?

Now that we have an understanding of what it takes to provide an optimum indoor growing environment we can start analyzing the cost-benefit of further optimizing and automating the system.  Please share with friends and follow to receive a notification when I publish the next section.

Section 1:  Let’s start by using an Arduino Nano on an Expansion Board to monitor the indoor gardening environment.  We will measure light intensity, ambient temperature, relative humidity, nutrient/water temperature.

Section 2:  Continue working with the Arduino Nano on an Expansion Board to control appliances in the indoor gardening environment.  We can continue working directly wired or we can start working with wireless communications.  Wired or Wireless?

Section 3:  Add an Arduino Uno using an LCD with Buttons Shield to provide a display and alerts.

Section 4:  Add the Raspberry Pi for remote access, notifications, data collection, and analytics.

Section 5:  More sensors:  moisture probe, pH, E.C., carbon dioxide level, flow-rate, liquid, float (liquid level switch).Peristaltic Pump

Advanced:  Using Dosing/Peristaltic Pumps for Nutrient Solution Management.

Using a Raspberry Pi and USB Camera  Use Raspberry Pi to monitor or collect snapshots of the garden using a USB webcam.

Do It Yourself:  hydroMazing Smart Garden System Kit

Kit includes wired and ready sensors and components for making the Controller Module (Arduino Nano) and Web Services Module (Raspberry Pi)?  Let me know, Contact Cory

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Managing Nutrient Solution Systems

A nutrient solution system typically consists of a two or three part liquid solution containing the essential diet for a plan added to clean tap water.  The manufacturer of the nutrient solution will include or reference a feeding schedule recommended for various common types of plants. Unfortunately, most minerals are mined and processed by the manufacturers, however, many offer an organic option while some specialize in only organic.

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nutrient starter kit

I recommend starting with General Hydroponics Flora Series Performance Pack, consisting of the main three liquid parts, several enhancements, and the pH test kit.  There is also an organic line of products. (Handy tip: If you ask General Hydroponics or other nutrient solution vendors for samples of their products, you can usually get free or discounted trial sizes.) A word of caution about miracle growing fertilizers, do not add any fertilizers other than those you know to be hydro-friendly, as it can cause a nutrient build-up harming your plants.

Making Your Own Nutrient Solutions

There are several challenges involved in making your own nutrient solution.  Sourcing the raw minerals needed, breaking-down properly so that the plants are able to absorb the nutrients, and filtering out unwanted materials that will clog the flow of nutrient solution through the system while maintaining a proper pH and hoping that you didn’t inadvertently introduce an undesirable pest into a closed-system.

Experiment with microfungals:  Make your own hydroponic compost tea

Nutrient Solution Management

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The most common vessel for transporting and storing water is the 5-gallon plastic bucket, also commonly available in 3-gallon as well.  The most common method for managing liquid is to use ½” diameter vinyl tubing and fittings.

If we do not monitor the nutrient solution concentration and the pH then the plants will reach a point where they will show signs of stress.

What is EC?

The electrical conductivity (EC) of water estimates the total amount of solids dissolved in water -TDS, (Total Dissolved Solids). TDS is often measured in ppm (parts per million). In hydroponics, this measurement is used to determine the approximate concentration of nutrient solution to water.

As the nutrient solution level decreases it needs to be replenished with freshwater, otherwise the nutrient solution becomes more concentrated and some plants won’t respond well. Add fresh water to bring the concentration back to the level it was when started, often referred to as “topping-off.”

What is pH?

The pH of water is an important measurement whether you are gardening indoors or outdoors, soil or soilless, because it affects whether a plant can properly take in nutrients.

Check the pH and EC periodically and compare it to what is expected for that plant at this stage of growth.  There is no need to adjust your pH or EC until it is necessary. There is a lot of misinformation out there about keeping the pH and EC regulated. If I were paranoid, I’d say it was a conspiracy from hydroponics manufacturers and retailers who want to sell more consumable product. Don’t get me wrong, proper pH and EC is important, even critical, to the success of a plant.  There are many hand-held EC devices available as well and if you are checking the E.C., it’s a great time to check the pH.  Therefore, I recommend a handheld pH tester such as the Oakton EcoTestr pH 2 Waterproof pH Tester, which is excellent for the home gardener and has been proven time and again to be accurate.

When do I need to adjust the pH?

Only under the following conditions:  pH is at or below 5.0 or above 6.5

AFTER at least 30 minutes from the time of topping-off or changing the nutrient solution.  I recommend using a solution made specifically for this purpose, pH Up and pH Down from General Hydroponics sparingly and only when necessary.

Flushing

Flushing means to literally flush empty the nutrient solution from the hydroponics system and replace it with fresh “good” tap-water. Then return the nutrient solution back to what it should be for the phase of growth. When in doubt, flush the system and refresh the nutrients. Otherwise, it’s recommended to flush your recirculating system every 7 – 14 days. When I grow, I try to keep the nutrient solution working as long as possible, however, salts build-up over time and it is good to flush with fresh water from time to time.

 

More Info:

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The Decider

 

The Coreconduit: Garden Controller System was the first version of the hydroMazing project .  The author of the Instructable drones on and on about healthy plants requiring attention and boredom until,

“…I’ve programmed into the Arduino a function I called, “TheDecider” that makes decisions based on maintaining optimum environmental conditions for growing plants. I added 2.4Ghz Wireless Radio Transceiver modules and a modular receiver system so that data is transmitted to within 1000 feet.”

TheDecider” was originally hardcoded with specific values that were fixed in place until I changed them in the Arduino sketch, recompiled, and uploaded.  There are two types of decisions that TheDecider executes, timed-based, and sensor-based rules.  The time-based rules simply compare the current time to the last time the appliance was turned-on or off.  The sensor-based rules use a minimum value threshold and a maximum value threshold that are compared to the current sensor reading and then execute the corresponding action for the appliance.  For example, if the temperature is below 55° then turn-off the ventilation fans; if the temperature is above 80° then turn-on the ventilation fans.  Each appliance has corresponding rules for sensor reading thresholds, time-based automation, and a combination of both, priority depending on the order of the rules.

Today’s hydroMazing uses the Raspberry Pi to provide an interface to the rules and the notifications.  The Pi communicates with the Arduino Nano microcontroller wirelessly sending updates and receiving data. TheDecider is a rules engine that executes the checks sent to it from the Pi.  The settings are stored in the EEPROM of the Arduino Nano allowing it to operate without further communications with the Pi.  hydroMazing doesn’t require an Internet connection to operate with the exception of receiving emails or text-alerts.  The Raspberry Pi can be configured to operate only within your WiFi network and be allowed to send emails and text-alerts.  Or, you can configure your router to allow access from outside and even assign a domain name, such as http://coreconduit.ddns.net.  See my Instructables for steps to a secure Pi.