final design report project title: wintergarden design report ... project title: wintergarden team...
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EEL 4924 Electrical Engineering Design
(Senior Design)
Final Design Report
25 April 2012
Project Title:
WinterGarden
Team Name:
Green Thumbs
Team Members:
Name: Ryan Consolver
Email: [email protected]
Name: Michael Inscho
Email: [email protected]
Project Abstract: Our project consists of building a self-maintaining hydroponic garden. This garden will be a 4’
by 2’ box standing at 6'3”. The garden will incorporate a variety of sensors into its design, monitoring
variables such as temperature, pH, CO2, humidity, water Electrical Conductivity, and light proximity.
The garden will use the touch based proximity sensor to maintain adequate distance between a hanging
light and the plants. The light will be raised and lowered by a motor and wire. Solenoid valves will be
used to adjust carbon dioxide levels, pH levels, maintain water volume and control nutrient
concentration. Microprocessor timers will control light ON/OFF periods as well as fan ON/OFF times.
All the monitoring information will be displayed on a LCD on the outside of the container.
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Table of Contents Project Features ........................................................................................................................................ 4
Analysis of Competitors ........................................................................................................................... 5
Concept/Technology/Project Archetecture Selection ............................................................................ 6
Flow Charts ............................................................................................................................................. 16
Distribution of Labor .............................................................................................................................. 18
User's Manual ......................................................................................................................................... 18
Bill of Materials ...................................................................................................................................... 18
Timeline ................................................................................................................................................... 19
References or Bibliograph: .................................................................................................................... 20
Figures
Lab Box ...................................................................................................................................................... 4
LM335A ..................................................................................................................................................... 5
HTM2500 ................................................................................................................................................... 6
MG811 ........................................................................................................................................................ 7
BRS pH Probe ........................................................................................................................................... 8
A1002 EC Probe ........................................................................................................................................ 9
Solid State Relay ..................................................................................................................................... 11
Solenoid .................................................................................................................................................... 12
12V Motor .............................................................................................................................................. 119
Tables
Labor Distribution .................................................................................................................................. 17
Bill of Materials ....................................................................................................................................... 18
Gantt Chart ............................................................................................................................................. 19
Diagrams
HTM2500 pin-out...................................................................................................................................... 7
MG811 pin-out .......................................................................................................................................... 8
TL082 pin_out ........................................................................................................................................... 9
LT1111 Circuit ........................................................................................................................................ 11
LM7805 pin_out ...................................................................................................................................... 11
IRF640 pin_out....................................................................................................................................... 13
Atmega324P pin_out ............................................................................................................................... 14
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Altium Designs
Temperature Sensor ................................................................................................................................. 6
Humidity Sensor ....................................................................................................................................... 7
CO2 Sensor ................................................................................................................................................. 8
pH Sensor ................................................................................................................................................... 9
EC Sensor ................................................................................................................................................ 10
Voltage Regulator ................................................................................................................................... 11
Relay Boards............................................................................................................................................ 12
Solenoid Boards ....................................................................................................................................... 13
Main Board .............................................................................................................................................. 14
Interconnectivity Boards ........................................................................................................................ 15
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Project Features/Objectives
Project Features The WinterGarden is intended for people without adequate time to care for their indoor plants. In indoor
gardening, the amount of light, CO2, nutrient concentration, and pH help determine the quality of the
finished product. WinterGarden will detect each parameter and adjust them to desired levels.
The purpose of the project is to design a self-sustaining garden. The plants will be grown
hydroponically. Normally people that grow plants with indoor hydroponics have to look after them
consistently and adjust the pH and light regularly.
To accomplish these things, this project includes:
Sensors for humidity, temperature, proximity, PH, Electrical Conductivity and CO2
Motor to move the light up and down
Solenoid valves to introduce pH UP, pH DOWN, and Nutrient Solutions
Relay controlled fan for the purpose of lowering temperature
Relay controlled CO2 solenoid
Relay controlled water and air pumps
Reed switches to determine water height and Door ajar.
Pull-up resistor Light Cage with ground sensing
Technical Objectives The objective of WinterGarden is to create a garden that can sustain a plant in a highly sutable
environment without much human interaction (people will have to set it up and fill CO2 tanks and liquid
adjustment solution).
The first problem that has to be resolved is power consumption. The lights used in such systems
can reach the upper hundreds of watts. We plan on using a 300 watt replacement florescent bulb.
Also, since this is a garden, we plan on it being wall powered.
Another issue to deal with is integrating all these sensors in the presence of the light. The
temperature of the light may affect some inputs. We plan on placing sensors in such a way to
reduce this effect and using sensors that have a reduced sensitivity to heat.
The garden should be big enough to grow some plants but not to be cumbersome. We were
thinking a 4’ by 2’ by 6’3” space.
The microprocessor will have to use a pulley system with motor driver to raise and lower the
light.
The pH and water content will be controlled by a solenoid valve.
CO2 level and air temperature will all be monitored and adjusted by the appropriate valves and
fan controls.
The water volume and parts per million will be monitored and adjusted as necessary.
Desired levels for pH and light times will adjust according to the plants life cycle. The
microprocessor will have a timer keeping track.
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Analysis of Competitive Products
Costs and Competitors The garden is expected to cost around $500. For this design, many expensive things such as reflecting
walls will not be included. Just looking at the lights, box, all sensors and the motor we are looking to at
least $300. All in one grow cabinets with less control can run from $500 on the cheap side to $2000 with
more expensive lights and containers. We will try to make it as cost effective as possible.
Other products similar to ours include Terrasphere, a soil based system.. Superbloom is
hydroponic with a similar system but the light remains stationary. There are also devices called grow
boxes which are just a reflective closed area for people to attach a light and take care of the plants on
their own. Figure 3 shows a similar product.
Figure 1-LabBox, a similar garden
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Concept/Technology/Project Architecture
Parts Temperature
LM335 Temperature Sensor
This sensor is easily implemented with a power supply, ground, and resistor.
To test WinterGarden’s temperature sensing capabilities, we will increase the
temperature of our system by switching on the light or placing a power strip of 100W
incandescent light bulbs inside the enclosure. The temperature change will be displayed
on the LCD and if the temperature is above the desired value, a fan will turn on to cool
the system down. We do not anticipate dealing with any temperature that needs to be
adjusted upwards as plants thrive in temperatures as low as 65 degrees Celsius and the
light cycle while provide nominal heat.
Figure 2- LM335A
Altium Design 1- Temperature Sensor
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Humidity WinterGarden will test for the correct humidity. We can make the sensor
think that humidity is high by holding our hand over the physical sensor. If an
increase of the actual humidity in the enclosure is required, we will place an electric
water kettle in the enclosure and boil water to create steam.
Figure 3- HTM2500
Diagram 1- HTM2500 Pinout
Altium Design 2- Humidity Sensor
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CO2
MG811 C02 Sensor with TL082 op amps
The MG811 has a very small output range and needs the gain for the ADC to be able
to distinguish enough for measurement. It also requires a high impedance amplifier
for accurate operation.
To test WinterGarden’s control of CO2 we will adjust the ambient in two
ways. First, to examine the system’s ability to monitor and maintain an average of
1500ppm we will open the door to the enclosure and allow it to equalize with the
ambient in the demonstration room. We will then shut the door, activating the
microprocessor’s CO2 control. When the microprocessor senses the CO2 is below
1500ppm, it will activate the CO2 solenoid, injecting the system with low pressure
CO2. When the CO2 sensor reads 1500ppm, the solenoid will shut off.
Second, to test the upper limits of our CO2 sensor, we will place dry ice in the
enclosure and observe a massive increase on our LCD output.
Figure 3- MG811
Diagram 2- MG811 Pinout
Altium Design 3- CO2 Sensor
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PH BRS PH Probe, with TL082 high impedance op amps
The TL082 serves as a gain and an offset, as PH probes give a
negative to positive voltage.
To test WinterGarden’s pH control, we will introduce pH
UP or pH DOWN into the system and our LCD will display the
pH changing. When the microcontroller detects the need for
change, the proper solenoid valve, controlling pH UP or pH
DOWN, will activate and return the pH to the desired range (5.5 -
6.5).
Figure 4- BRS pH probe
Altium Design 4- pH Sensor
Diagram 3- TL082 Pinout
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Electrical Conductivity Model A1002 EC flow through sensor
Takes an input of 12V and ground and gives an output
WinterGarden will maintain adequate nutrient supply in then hydroponic
reservoir. This will be handled in two ways. First, during the refresh cycle non-
balanced water will enter the hydroponic reservoir from the water storage
container. This water will first have its pH balanced within the range of 5.5-6.5,
likely a value of 6. The electrical conductivity should begin at around 300ppm for
plain water and increase after the balancing of the pH. Then, nutrient solution will
be added to the reservoir to increase the electrical conductivity to the desired level
depending on the nutrient solution. Second, this
EC value and the water level in the reservoir will be maintained by further
introduction of water and nutrient solution, as needed, following their uptake by the
growing plants.
Figure 5- A1002
Altium Design 5- EC Sensor
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Voltage Regulator
LT1111 and LM7805 Regulators
Used to change voltage from our 12V transformer to 6, 5, and –5.
Diagram 4- LT1111 Circuit
Diagram 5- LM7805 Pinout
Altium Design 6- Voltage Regulator
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Solid-State Relays
We will use solid state relays to control our wall power components.
Figure 6- SSR
Altium Design 7-1xRelay
Altium Design 8-4xRelay
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Solenoids
For controlling pH, electrical
conductivity, and C02 we will use
solenoid valves.
These will be switched on and off by
IRF640 MOSFETs activated by signals
from the microprocessor.
Figure 7- Solenoid
Diagram 6-IRF640 Pinout
Altium Design 9-2xSolenoid
Altium Design 10-3xSolenoid
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12V Motor
The motor we will use is a 1 RPM gear motor. The
purpose is to raise the light if the plant grows high enough
to touch it.
Light Proximity WinterGarden will maintain appropriate distance
between the hanging light and the growing plants. For our
application, the light has low heat dissipation, thus the
minimum distance required is non-contact. To test our
control, we will touch an electrical ground to the cage
around the light so that it detects contact. This could be as
simple as bending a plant branch to the cage or touching
the cage with a finger. When contact is detected, the motor
will activate and raise the light till non-contact is
established. When the contact is removed, the light will
stop. To subsequently lower the light, the manual
overdrive will be required. This will not be a weakness in
the design as plants do not grow down and plant height
can only be lowered by the user. The external manual
overdrive will allow adjustment to any possible height
within the enclosure.
Figure 8- 12V Motor
Diagram 7-Atmega324P Pinout
Altium Design 11-MainBoard
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Interconnectivity
Altium Design 11-Mux Board
Altium Design 12-LCD Board
Altium Design 13-Relay Board
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Flowcharts & Diagrams
Hardware Flowchart
The block diagram in figure 2 shows the various connections to the microprocessor.
Chart 1-Microprocessor connections
Software Flowchart
Our flowchart can be found below in figure 2. Since our project is mostly about controlling the plants
environment, we activate and deactivate many solenoids and relays in order to provide it. To avoid
constantly checking some sensitive parameters that have to settle, we will be using timers and interrupts
to check up on the values and then change them. Also, the water will have to be refilled after periods of
time that will be set, such as weekly or monthly.
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Chart 2-Software Flowchart
Distribution of Labor Since there are so many parts in this project, we plan on separating it into creating circuits for the
various sensors. We plan on working together as much as possible to complete coding and analog
circuitry. Table 2 shows the estimated distribution of labor.
Ryan Consolver Michael Inscho
Research 50 50
PH Sensor Design 50 50
CO2 sensor design 70 30
Humidity and Temperature
Sensor Design
50 50
Nutrient Sensor Design 50 50
LCD Interface 30 70
Solenoid Interface 70 30
Motor Interface 30 70
PCB Soldering/Testing 50 50
Physical construction 50 50
Sensor Boards Altium Design 70 30
Main Board Altium Design 30 70
Light Cage Mechanism 50 50
Debugging 50 50 Table 1-Labor Distribution
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User’s Manual
The device has two modes and 4 user inputs. There is a ON/OFF power switch, a Two-
Month/Three-Month cycle switch, a Vegetation Cycle Reset Button, a Flowering Cycle Reset Button
and a Lower Light button. The ON/OFF switch powers the device. The Cycle Switch chooses a total
grow length. The Vegetation/Flowering reset buttons return the cycle count to the beginning of the
pushed cycle. The Lower Light Button lowers the light.
Bill of Materials (BOM)
Parts List
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Gantt Chart / Project Schedule
Timeline The Gantt chart in figure 4 shows the project timeline and when we plan on working on different aspects
of the project.
Table 3-Gantt Chart
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References or Bibliography Electronic Components Distributor Digikey. http://digikey.com
http://hydroponicgarden.net/hydroponic-grow-cabinets-c-10.html
References
http://mil.ufl.edu/4924/
MG811
http://www.parallax.com/Portals/0/Downloads/docs/prod/sens/MG811Datasheet.pdf
LM335A
http://www.ti.com/lit/ds/symlink/lm335.pdf
HTM2500
http://www1.futureelectronics.com/doc/MEASUREMENT%20SPECIALTIES/HTM2500.pdf
TL082
http://www.ti.com/lit/ds/symlink/tl082.pdf
LM7805
http://www.sparkfun.com/datasheets/Components/LM7805.pdf
LT1111
http://cds.linear.com/docs/Datasheet/1111fd.pdf
IRF640
http://www.vishay.com/docs/91036/91036.pdf
12V Supply
http://products.cui.com/CUI_ETSA190342UD_Datasheet.pdf?fileID=2620
pH Probe
http://www.bulkreefsupply.com/store/products/monitors-controllers/brs-ph-and-orp-probes/brs-brand-
ph-probe.html
EC Probe
http://webpages.charter.net/tdsmeter/manuals/A1002.pdf
Solenoids
http://www.dudadiesel.com/choose_item.php?id=W04010
http://www.dudadiesel.com/choose_item.php?id=W040B10
Water pump
http://www.sunlightsupply.com/p-13149-ecoplus-eco-396-submersible-pump.aspx
Air pump
http://www.sunlightsupply.com/PDF/HeavyDutyPump_Instructions.pdf
Atmega324P
http://www.atmel.com/Images/doc8011.pdf
SN754410_Motor Driver
http://www.ti.com/lit/ds/symlink/sn754410.pdf
Light
http://www.lowes.com/pd_46931-75774-
65TN_?productId=3197521&site=shopLocal&utm_campaign=bazaarvoice&utm_medium=SearchVoice
&utm_source=RatingsAndReviews&utm_content=Default
pH Up/Down
http://generalhydroponics.com/site/index.php/products/maintenance/ph_buffers/ph_up/
http://generalhydroponics.com/site/index.php/products/maintenance/ph_buffers/ph_down/
Nutrients
http://www.hydro-organics.com/home/index.php?productID=702
http://www.hydro-organics.com/home/index.php?productID=667
http://www.hydro-organics.com/home/index.php?productID=668