LeafAlone
Hydroponics System
GROUP 9
KHALID AL CHARIF
MATTHEW DILEONARDO
MIKE LOOMIS
JUSTIN WALKER
Sponsor: Duke Energy
Work Distribution
Name
Hardware
PCB
Mike
X
X
Khalid
X
Matt
X
Justin
Software
Communications
Power
X
X
X
X
2
Hydroponics Basics
Hydroponic Essentials:
Balanced nutrients and pH (varies
by plant)
Adequate water and oxygen
supply
Light source
Deep Water Culture (DWC) setup
shown in figure to the right
3
Motivation
Hydroponic gardening requires plant specific knowledge base
◦ Each plant varies in optimal pH and nutrient levels
Setup can be lengthy and requires daily maintenance
◦ Monitor and adjust pH, water, and nutrient levels
Traditional soil gardening can lead to subpar plant growth
◦ Hydroponics allow for maximum water and nutrients uptake for best results
◦ Competing products cost +$2000 for similar functionality
4
Goals and Objectives
Create system that monitors and adjusts hydroponic variables
autonomously
◦ Notify user via email/text message if action required
Eliminate lengthy setup/research by pre loading user specified plant
values
Low maintenance
◦ No need for daily monitoring or adjustments
System able to function using solar power
◦ Promote sustainable energy
Produce results greater than soil based gardening
5
Specifications
Attribute
Battery Life Without Charge
Number of Plants
Weight (Empty)
Dimensions
Value
24 hours
1-2
Approx. 5lbs.
6 months
Operating Temperature
10 - 35◦C
Reservoir Volume
1-15 liters per day
75 L
Working Temperature
10-40 ◦C
Sensor Measurements
25 minutes intermittently
Electrical Conductivity Range
pH Sensor Range
Value
Liquid Dispenser Flow
10-50mL min−1
Air Pump Flow
500-1000mL min−1
Enclosure Sealing
Weather resistent
Battery Capacity
5Ah
Battery Voltage
12V
Solar Panel Power Output
20W
Communications
Wi-Fi
Data Rate
6-54Mbps
Maximum Signal Power
15dBm
CPU
8bit AVR
Microprocessor Speed
8MHz
30" x 20" x 14"
Total Lifespan
Water Consumption
Attribute
100-3000 ppm
0-14 pH
6
Overall Block Diagram
Power Supply
Sensors
pH Probe
pH
Amplifier
EC Probe
EC Circuit
Phototransistor
120V AC
Solar
Panel
AC to DC
Converter
Charge
Controller
Battery
ATmega328
Wi-Fi
Water
Level
Communications
pH Buffer
Pump
Nutrient
Pump
Motors
Air Pump
Air Filter
7
Device Enclosure
Requirements
Rainproof enclosure to protect
electronics from moisture.
Easily mountable on most generic
reservoir
Plastic container to be easily produced
and modified
6.3in.
4.3in.
7in.
Enclosure Xray View
8
Sensors
Sensors
pH Probe
pH
Amplifier
EC Probe
EC Circuit
Phototransistor
120V AC
Solar
Panel
AC to DC
Converter
Charge
Controller
Battery
ATmega328
Wi-Fi
pH Buffer
Pump
Nutrient
Pump
Air Pump
Water
Level
Air Filter
9
pH Content
pH of the water needs to stay within a certain range
(pH 5.5-7)
◦ Allows for optimal nutrient absorption
◦ Sensor provides feedback on current pH level
◦ pH buffer solution adjusts current pH level
pH Sensor
◦ Glass electrode probe
◦ BNC connector to microcontroller
◦ Generates voltage that corresponds to
pH
S200C Sensorex Probe
10
pH Problems and Solutions
PROBLEMS
1.
Interfacing a high impedance
probe with a microcontroller
2.
Calibrating the probe
3.
Filtering out unwanted signals
SOLUTIONS
1.
Using low input bias current op
amps as buffer to the
microcontroller
2.
Using trimming
potentiometers to adjust gain
and offset signals
3.
Using delay on probe
measurements to allow
outside voltages to dissipate
11
pH Probe Amplifier Schematic
Gain Stage
Precision
Voltage
Reference
Voltage
Offset
12
Electrical Conductivity
Electrical conductivity (EC) corresponds
with the nutrients level in the water (parts
per million)
◦ Ppm measurements allow device to regulate
nutrient supply to the plants
◦ Initial water ppm is used as baseline
reference
EC probe is used to measure conductivity
◦ AC voltage input
◦ DC voltage output
Sensorex CS150 EC Probe
13
EC Problems and Solutions
PROBLEMS
1.
Enabling the circuit to be
toggled on/off so that it will
not interfere with other
sensors
SOLUTIONS
1.
Use MOSFET schematics to
allow positive and negative
voltage rails to be grounded
2.
2.
Generate two power supplies
for oscillator signal
Use an buck/boost dc to dc
converter IC in a voltage
inverting schematic
3.
Rectifying AC signals to precise 3.
DC voltage levels
Implement precision voltage
rectifier
14
EC Probe Reference Schematic
15
Additional Sensors
Photoresistor
◦ Measures general light level on plant
Water Level Float Switch
◦ Measures if water level falls below a certain point
◦ A float valve attached to a garden hose will keep the water reservoir full
Water Level Switch
Light Sensor
16
Motors
pH Probe
pH
Amplifier
EC Probe
EC Circuit
Phototransistor
120V AC
Solar
Panel
AC to DC
Converter
Charge
Controller
Battery
ATmega328
Wi-Fi
pH Buffer
Pump
Nutrient
Pump
Air Pump
Water
Level
Motors
Air Filter
17
Diaphragm Pump
Air Pump Specifications
Cost
$7.95
Voltage
12 VDC
Current
~30 mA
Airflow
2 L/m
Pressure
350 mmHg
2.75in.
1.125in.
KPM27H-12B5
12VDC Air Pump
18
Nutrient/pH Buffer Pumps
Air Pump Specifications
Cost
$56.94
Lifetime
500-1000 hrs
Voltage
12 VDC
Current
~100-260 mA
Flow
20-80 ml/min
Max. Pressure
Height
8 m (Water)
2.9in.
2in.
SR 10/30 12V
Peristaltic Pump
19
Motor Control Schematic
20
Communications
pH Probe
pH
Amplifier
EC Probe
EC Circuit
Phototransistor
120V AC
Solar
Panel
AC to DC
Converter
Charge
Controller
Battery
ATmega328
Wi-Fi
pH Buffer
Pump
Nutrient
Pump
Air Pump
Water
Level
Communications
Air Filter
21
Atmega16u2 Microprocessor
Specifications
Value
Flash Memory
16 kilobytes
Pins
32
Operating Frequency
16MHz
CPU
8-bit AVR
• USB Interface Capable
• Firmware allows USB to SPI interface
22
Atmega328p Microprocessor
Specifications
Value
Flash Memory
16 kilobytes
Pins
32
Operating Frequency
16MHz
CPU
8-bit AVR
• Main processor used for program memory
23
Main Processor Schematic
24
CC3000 Wi-Fi Schematic
3.3V Logic Level
Power Supply
Power Supply
pH Probe
pH
Amplifier
EC Probe
EC
Amplifier
Phototransistor
120V AC
Solar
Panel
AC to DC
Converter
Charge
Controller
Battery
ATmega328
Wi-Fi
pH Buffer
Pump
Nutrient
Pump
Air Pump
Water
Level
Air Filter
26
Power Subsystem Block
Diagram
3.3V
.5W
Solar
Panel
5V
0.15W
CC3000 WiFi
Microcontroller
+/- 5V
0.35W
50W
Charge
Controller
EC Probe
pH Correction
Pump
Battery
12V
50W
Air Pump
12V
3.2W
Nutrients
Pump
27
Power Subsystem
Requirements
1.
Safe outdoors
2.
12V, 1 Amp output
3.
24 hours of Battery life
4.
Solar Energy Recharging
Printed Circuit Board
Prototype design created with
Altium
◦ 2 Layers, Standard Spec
Prototype manufacturer:
◦ Sunstone Circuits
Specifications
Dimensions
3.125 x 3.900 in
Minimum
Purchase
2 Boards
Turn Time
3-5 days
29
PCB Board Layout
30
PCB Rendering
31
PCB Problems and Solutions
PROBLEMS
1.
2.
Cross signal interference
causing high speed
connections to fail
Populating ~80 components
SOLUTIONS
1.
Using peripheral board for WiFi
and system programming
2.
Used a stencil and solder paste
and reflowed the components
into place
32
System Activity Diagram
33
System Software
Built using Arduino IDE 1.0.5 Rev.2
◦ Libraries Used:
◦ AdafruitCC300
◦ SPI
◦ String
◦ Utility/Debug
◦ Utility/Socket
Runs local host TCP server listening on port 7
Sends HTTP GET requests with sensor data to client server
34
Server Activity Diagram
35
Server Software
Server written using Node.js platform
◦ Lightweight
◦ Non-blocking architecture allows for easy scalability
◦ Small learning curve
◦ All code written in JavaScript
Communicates with system using TCP socket connections
◦ Send data on port 7
36
Database Tables
Plants
PK
User
ID Number
Youth_EC_Minimum
Youth_EC_Maximum
Adult_EC_Minimum
Adult_EC_Maximum
PH_Maximum
PH_Minimum
Name
PK
Sensor
ID Number
Device_ID
Email
Password
First_Name
Last_Name
Phone_Number
Phone_Carrier
Plant_Name
PK
ID Number
Timestamp
Device_ID
IP_Address
PH_Address
PH_Level
EC_Level
Temperature
Phototransistor_Level
Water_Level
37
Database Design
Using non-relational MongoDB
◦ Fast access time
◦ Easy to implement API with Node.js server
3 Database Documents created
◦ Plants
◦ Users
◦ Sensor Entry
38
Client Activity Diagram
39
Client Website
40
Client Website Features
Login/Logout Authentication
User Registration
User can choose type of plant to be grown
◦ Plant pH and EC threshold values sent to system after user selects/modifies
plant type
Data Log
◦ Table view of all sensor test data entries stored in the database
Demo
Demo 2
41
Demo 1
42
Demo 1 Tasks
1.
2.
3.
4.
Choose tests to be performed on command
TCP socket connection established to system with test information
System runs selected tests and returns results to server
Server saves results in the database and displays all entries in the
database
43
Demo 2
44
Demo 2 Tasks
1.
2.
Mimics actual system functionality
User specifies:
◦ time interval between sensor tests
◦ the number of tests to be run
3.
4.
5.
6.
Server sends values to system using TCP socket connection on port 7
System runs tests according to parameters
System replies to server using HTTP GET request
The server then stores the sensor entries in the database
45
Software Problems and
Solutions
PROBLEM
SOLUTION
Client server not receiving all data
sent from system during TCP
socket data transfer
Add 10 ms delay after transfer of
each character to allow time for
server to receive all transmissions
Arduino strings not easily
compatible with HTTP GET
requests functions
Converted strings to character
arrays
46
Component Cost
Part
SR10/30 Liquid Pump x2
EC Probe
pH Probe
12VDC Air Pump
CC3000 WiFi Breakout
Fibox PC 16/16 L3 Enclosure
Polycarbonate Sheet
Epoxy/Sealing Compounds
Charge Controller
PCB Manufacturing
PCB Components
Final Production Cost
Cost
$113.88
$70.24
$55.00
$7.95
$34.95
$30.46
$15.28
$15.00
$24.95
$150.00
$622.90
$1140.60
47
Questions?