LeafAlone Hydroponics System

1. LeafAloneHydroponics System Group 9 Khalid Al Charif Matthew DiLeonardo Mike Loomis Justin Walker Sponsor: Duke Energy

2. Work Distribution

3. 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

4. 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

5. 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

6. Specifications

7. Overall Block Diagram 120V AC Solar Panel Power Supply Sensors AC to DC Converter Charge Controller pH Probe pH Amplifier EC Probe EC Circuit Battery Photo-transistor ATmega328 Wi-Fi pH Buffer Pump Nutrient Pump Air Pump Water Level Air Filter Motors Communications

8. 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

9. Sensors 120V AC Solar Panel Sensors AC to DC Converter Charge Controller pH Probe pH Amplifier EC Probe EC Circuit Battery Photo-transistor ATmega-328 Wi-Fi pH Buffer Pump Nutrient Pump Air Pump Water Level Air Filter

10. 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

11. pH Problems and Solutions Problems Solutions Using low input bias current op amps as buffer to the microcontroller Using trimming potentiometers to adjust gain and offset signals Using delay on probe measurements to allow outside voltages to dissipate • Interfacing a high impedance probe with a microcontroller • Calibrating the probe • Filtering out unwanted signals

12. pH Probe Amplifier Schematic Gain Stage Precision Voltage Reference Voltage Offset

13. 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

14. EC Problems and Solutions Problems Solutions Use MOSFET schematics to allow positive and negative voltage rails to be grounded Use an buck/boost dc to dc converter IC in a voltage inverting schematic Implement precision voltage rectifier • Enabling the circuit to be toggled on/off so that it will not interfere with other sensors • Generate two power supplies for oscillator signal • Rectifying AC signals to precise DC voltage levels

15. EC Probe Reference Schematic

16. 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

17. Motors 120V AC Solar Panel AC to DC Converter Charge Controller pH Probe pH Amplifier EC Probe EC Circuit Battery Photo-transistor ATmega328 Wi-Fi pH Buffer Pump Nutrient Pump Air Pump Water Level Air Filter Motors

18. Diaphragm Pump 2.75in. 1.125in. KPM27H-12B5 12VDC Air Pump

19. Nutrient/pH Buffer Pumps 2.9in. 2in. SR 10/30 12V Peristaltic Pump

20. Motor Control Schematic

21. Communications 120V AC Solar Panel AC to DC Converter Charge Controller pH Probe pH Amplifier EC Probe EC Circuit Battery Photo-transistor ATmega328 Wi-Fi pH Buffer Pump Nutrient Pump Air Pump Water Level Air Filter Communications

22. Atmega16u2 Microprocessor • USB Interface Capable • Firmware allows USB to SPI interface

23. Atmega328p Microprocessor • Main processor used for program memory

24. Main Processor Schematic

25. CC3000 Wi-Fi Schematic 3.3V Logic Level

26. Power Supply Power Supply 120V AC Solar Panel AC to DC Converter Charge Controller pH Probe pH Amplifier EC Probe EC Amplifier Battery Photo-transistor ATmega328 Wi-Fi pH Buffer Pump Nutrient Pump Air Pump Water Level Air Filter

27. Power Subsystem Block Diagram 3.3V .5W CC3000 WiFi Solar Panel 5V 0.15W EC Probe Microcontroller +/- 5V 0.35W 50W Charge Controller Battery pH Correction Pump 12V 50W Air Pump 12V 3.2W Nutrients Pump

28. Power Subsystem Requirements • Safe outdoors • 12V, 1 Amp output • 24 hours of Battery life • Solar Energy Recharging

29. Printed Circuit Board • Prototype design created with Altium • 2 Layers, Standard Spec • Prototype manufacturer: • Sunstone Circuits

30. PCB Board Layout

31. PCB Rendering

32. PCB Problems and Solutions Problems Solutions Using peripheral board for WiFi and system programming Used a stencil and solder paste and reflowed the components into place • Cross signal interference causing high speed connections to fail • Populating ~80 components

33. System Activity Diagram

34. 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

35. Server Activity Diagram

36. 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

37. Database Tables

38. 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

39. Client Activity Diagram

40. Client Website

41. 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

42. Demo 1

43. Demo 1 Tasks • 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

44. Demo 2

45. Demo 2 Tasks • Mimics actual system functionality • User specifies: • time interval between sensor tests • the number of tests to be run • 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

46. Software Problems and Solutions Problem Solution Add 10 ms delay after transfer of each character to allow time for server to receive all transmissions Converted strings to character arrays • Client server not receiving all data sent from system during TCP socket data transfer • Arduino strings not easily compatible with HTTP GET requests functions

47. Component Cost

48. Questions?