Introduction: Smart Plant Growth Chamber
I come up with new idea which is smart plant growth chamber.The growth of plants in outer space has elicited much scientific interest. In the context of human spaceflight, they can be consumed as food and/or provide a refreshing atmosphere.Currently N.A.S.A. use plant pillows to grow food in International Space Station.
So i come up with idea to step further.
Problems to grow food in space:
It is main obstacle to grow food in space it effect the growth of plants in several ways :
1 you can not watering the plants properly because there in no gravity so water can not be provided by water sprinklers and other conventional method which are used on earth .
2 Water can not reach to roots of plant because there is no gravity.
3 Growth of roots also affect by gravity. (roots of plant go downwards and plant grow upwards) So roots of plants never grow in right direction.
1.There is lot of radiation in space so it is harmful for plants.
2.Radiation form solar wind also effect plants.
3.Lot of ultraviolet rays also harmful for plants.
1. There is lot of temperature variation in space (temperature can go up-to hundred degrees and down to minus hundred degrees).
2. temperature increase water evaporation so plants can not survive in space.
1. Monitoring of plants is very difficult in space because person continuously monitoring many factors such as temperature , water and radiation.
2. Different plants require different needs of resources, If there are different plants monitoring become more difficult.
So i come up with idea that trying to eliminates all these obstacles. It is chamber for growing food in space at very low cost.It contain all resource and technology built in which overcome many difficulties. So lets get stared !!!
What this chamber is capable of:
1. Eliminate effect of gravity.
2. Providing proper water to plants roots. (Controllable - Manually, automatically)
3. Providing artificial lighting to plants for photosynthesis.
4. Minimize effect of radiation.
5. Sensing environment such as soil temperature, moisture, environment temperature, humidity , radiation, pressure and display real time data on computer.
Step 1: Component Required :
1. ESP32 (Main processing Board you can also use other boards).
2. DHT11 or DHT-22. (DH22 provides better accuracy)
3. DS18b20 (Water proof metal version).
4. Soil moisture sensor .
5. Water pump. (12Volt).
6. Sheet of plastic.
7.12 volt dc fan.
8. Gas sensors.
10. Servo motor.
11. Glass sheet.
12. Electrostatic sheet.
13. 12 volt relay.
14. BMP 180.
15. 7805 Voltage regulator.
16.100uF, 10uF capacitor.
17. Car roof light (LED or CFL).(Color defined further).
18. SMPS Power supply (12volt - 1A if you drive pump from separate supply otherwise up-to 2 amps power supply)
Step 2: Software Requirement:
1. Arduino IDE.
3. ESP32 Installation in Arduino IDE.
4. ESP32 Libraries. (Many libraries are different from Arduino libraries).
Step 3: Make Container and Watering System:
Make a plastic container of any size according to requirement or space available. Material used for container is plastic so can not it can not dispose by water (It can also made from metals but it increase cost and also weight because there is weight limit of rocket)
Problem: There is no gravity in space. Water drops stay free in space (as shown in picture by N.A.S.A.)and never reach bottom of soil so watering with conventional methods are not possible in space.
Also small particle form soil floating in air.
Solution: I put small water pipes in soil (it has small holes) at center and pipes are attached to pump.When pump turns on water come out form small holes of pipe to bottom of soil so it easily reach to roots of plant.
Small fan is attached on top of chamber (air flows upwards to downwards ) so it provide pressure to small particle and avoid to float outside the chamber.
Now put soil into container .
Step 4: Soil Sensors:
i insert two sensor in soil. First is temperature sensor (DS18b20 Waterproof). Which detect soil temperature.
Why we need to know temperature and humidity of soil ?
Heat is the catalyst for many biological processes. When soil temperatures are low (and biological processes slow), certain nutrients are made unavailable or less available to plants. This is particularly true in the case of phosphorus, which is largely responsible for promoting the development of roots and fruit in plants. So, no heat means less nutrients results poor growth. Also high temperature are harmful for plants.
Second is humidity sensor. Which detects humidity of soil if moisture in soil reduces from predefined limit , motor turns on, when moisture reach its upper limit motor automatically turn off. Upper limit and lower limit depend and vary from plants to plant. This results in closed loop system. Water is done automatically with-out interference of person.
Note. Water requirement for different for different plants. So there is need to adjust minimum and maximum water level. It can be done from potentio-meter if you are using digital interface otherwise it can be changed in programming.
Step 5: Making Glass Walls
There are walls on back side of container with electrostatic film on it. Since there is no magnetic field which protects us from solar winds. I use a simple glass sheet but cover it with electrostatic sheet. Electrostatic sheet prevent charge particle of solar wind. It is also helpful to minimize radiation effect in space. it also avoid to float soil and water particle into air.
Why we need electrostatic protection ?
Earth's molten iron core creates electric currents that produce magnetic field lines around the Earth similar to those associated with an ordinary bar magnet. This magnetic field extends several thousand kilometers out from the surface of the Earth. Earth's magnetic field repel charge particle in form of solar wind and avoid to enter in earth's atmosphere. But there is no such protection available outside earth and on other planets. So we need other artificial method to protect us as well as plants from these charge particle. Electrostatic film is basically a conductive film so it do not allow to enter charge particle inside.
Step 6: Building Shutter:
Every plant has own need of sun-light. Exposure in sun for long time and high radiation also harmful for plants. Shutter wings are attached out side of mirror then connected to servo motors. Angle of opening wing and allow light to come in which is maintained by main processing circuit
A light detecting component LDR (light dependent resistor) is connected to main processing circuit How this system work:
1. In excessive radiation and light (Which is detected by LDR) it closes wings and eliminated light to come within. 2. Each plant has it own need of sun-light. Main processing circuit note time to allow sunlight after this particular time winds are closed. It avoid extra lighting to reach in the chamber.
Step 7: Environment Sensing and Control:
Different plant require different environment condition such as temperature and humidity.
Temperature : To sense environment temperature DHT-11 sensor is used (DHT 22 can be used to achieve high accuracy). When temperature increases or decreases from prescribed limit it warn and turn on outer fan.
Why we need to maintain temperature ?
The temperature in outer space is 2.73 Kelvin (-270.42 Celsius, -454.75 Fahrenheit) in dark side (where sun not shine). The sun-facing side , temperature can reach scalding hot temperatures of about 121 C (250 degrees F).
Humidity is the amount of water vapor in the air relative to the maximum amount of water vapor that the air can hold at a certain temperature.
Why we need to maintain humidity ?
Humidity levels affect when and how plants open the stomata on the undersides of their leaves. Plants use stomata to transpire, or “breathe.” When the weather is warm, a plant may close its stomata to reduce water losses. The stomata also act as a cooling mechanism. When ambient conditions are too warm for a plant and it closes its stomata for too long in an effort to conserve water, it has no way to move carbon dioxide and oxygen molecules, slowly causing the plant to suffocate on water vapor and its own transpired gases.
Due to evaporation (from plant and soil) humidity increase rapidly. It not only harmful for plants but also harmful for sensor and glass mirror. It can be neglected with two ways.
1. Plastic paper on top of surface prevent humidity easily. Plastic paper is spread on top surface of soil with opening in it for substrate and seed (Plant grow in it). It is also helpful during watering.
Problem of this method is that the plants with larger roots need air into soil and roots. plastic bag stop air to reach its roots completely.
2. Small fans are attached on top roof of chamber. Humidity in chamber is sense by Hygrometer which is inbuilt in (DHT-11 and DHT-22). When humidity increases from limit fans are turn on automatically, At lower limit fans are stopped.
Step 8: Eliminate Gravity:
Due to gravity stems grow upward, or away from the center of Earth, and towards light. Roots grow downward, or towards the center of Earth, and away from light. Without gravity plant did not inherit ability to orient itself.
There are two methods to eliminating gravity
1. Artificial Gravity:
Artificial gravity is the creation of an inertial force that mimics the effects of a gravitational force, usually by rotation result on producing centrifugal forces .This process is also called pseudo-gravity.
This method is too expensive and very difficult. there is too much chances of failure. Also this method can not tested on earth properly.
2.Using Substrate : This is too easy method and also cloth effective. Seeds are kept inside a small bag which is called Substrate seed are kept under substrate which provide right direction to roots and leafs as shown in picture. It helps to grow roots downwards and plant leafs upwards.
It is a cloth with holes. Since seed are inside It allow water to come in and also allows roots to come out and penetrate into soil. Seed is kept under 3 to 4 inches depth under soil.
How to put seed under soil and kept its position??
I cut plastic sheet with length of 4 to 5 inched and form a groove on front of it. Place this tool on half length of this cloth (groove side). Put seed into groove and wrap the cloth around . Now insert this tool into soil. Get tool out from soil so seed and substrate get into soil.
Step 9: Artificial Sunlight:
In space sunlight all the time is not possible so artificial sunlight may be required. This is done by CFL and newly coming LED lights. I use CFL light which is blue and red in color not too much bright. These lights mounted on top roof of chamber. This provide full spectrum of light (CFL's are used when there is requirement of of light with high temperature, whereas LED's are used when plants require no heating or low heating. this can be drive manually, remotely of automatically (controlled by main processing circuit).
Why i use combination of blue and red color?
Blue light fits with the absorption peak of chlorophylls, which do photosynthesis to produce sugars and carbons. These elements are essential for plant growth,because these are the building blocks for plant cells. However, blue light is less effective than red light for driving photosynthesis. This is because blue light can be absorbed by lower-efficiency pigments like carotenoids and inactive pigments like anthocyanins. As a result, there is a reduction of blue light energy that makes it to the chlorophyll pigments. Surprisingly, when some species are grown with just blue light, plant biomass (weight) and photosynthesis rate are similar to a plant grown with just red light.
Step 10: Visual Monitoring:
I use LABview for visual monitoring of data and control also because LABview is very flexible software. It high speed data acquisition and easy to operate. It can be wired or wire-less connect to main processing circuit. Data coming from main processing circuit (ESP-32) is formatted in displayed on LABview.
Steps to be followed:
1. Install LABview and download. (no need to install Arduino Add-ons)
2. Run the vi code given below.
3. Connect USB port into your PC.
4. Upload Arduino code.
5. COM port shown in your labview (if windows for linux and MAC "dev/tty") and indicator shows your port is connected or not.
6. Finish!! Data from various sensors displayed on screen.
Step 11: Prepare Hardware (circuit):
The circuit diagram is shown in figure. you can also download PDF given below.
It consist of following parts:
Main processing circuit:
Any board that is compatible with arduino can be used such as arduino uno, nano, mega, nodeMCU and STM-32. but ESP-32 use due to following reason :
1. It has inbuilt temperature sensor so at high temperature situation putting processor to deep sleep mode is possible.
2. Main processor is shielded with metal so there are less radiation effect.
3. Internal hall effect sensor is used to detect magnetic field around the circuitry.
All sensor are running on 3.3 volt power supply. Voltage regulator inside ESP-32 provides low current so it can be overheated. To avoid this LD33 voltage regulator is used.
Node: I applied 3.3 volt supply because in use ESP-32(Also same for nodeMCU and STM-32). It you are using arduino you can also use 5 volts
Main power supply:
12 volt 5 amp SMPS is used. you can also used regulated power supply with transformer but it is linear supply so it is designed for specific input voltage so output will be changed as we switch 220 volt to 110 volt. (110 volt supply is available in ISS)
Step 12: Prepare Software:
Steps to be followed:
1.Installing Arduino: If you don't have arduino you can download from link
Step 13: Prepare LABview:
1. Download LABview from this link
2. Download vi file.
3. Connect USB Port. Indicator show port is connected or not.
Participated in the
Growing Beyond Earth Maker Contest