Calvin College Senior Design Team 11
Aaron Maley
Jeff Overweg
Simeon Eisen
Jacob VanderWall
THE TEAM

Simeon Eisen

Jeff Overweg

Aaron Maley

Jacob VanderWall
A NICHE IN THE MARKET



There are current pool care systems, but they
are not created and marketed to the average
residential pool owner.
Current systems range in price from $1200-$7000
for just the controller alone
A product with the features of the high end
systems, at a price that residential pool owners
can afford would be a very viable real world
product
THE PROJECT


To create an affordable chemical control
system for the residential pool market.
What Does it Do?

Sample pool water at regular intervals


Dispense chemicals into the pool pump system


Microprocessor controlled system
Granule feed system
Broadcast pool data via website

Wireless module
MICROCONTROLLER SYSTEM

Goal:


Use an embedded microcontroller to control
water testing, chemical dispersal, local display,
and data being sent to web server.
Major Components and Interfaces:
Sensors and Related Circuits
 Chemical Dispersal Control
 Local Display/User Interface
 Analog Data to Web Server

MICROCONTROLLER SYSTEM

Full System Diagram
MICROCONTROLLER SYSTEM

Sensors and Related Circuits

Three main sensor inputs


Temp, pH, ORP
How are the amounts of Chemicals Needed
Calculated?
pH, ORP, temperature readings and size of pool are
used to calculate the required dosage
 Dosage precision can exceed 0.25 oz

FREE CHLORINE CALCULATION
Free Chlorine as a Function of pH and ORP
10
6.5
7
9
7.5
8
Free Chlorine (ppm)
8
7
8.5
6
Power
(6.5)
5
4
Power (7) y = 1E-42x14.878
R² = 0.9991
3
Power
(7.5)
2
y = 3E-58x20.099
R² = 0.9984
1
Power (8) y = 3E-69x23.734
R² = 0.9995
0
Power
(8.5)
550
600
650
700
750
ORP (mV)
800
850
900
y = 1E-82x28.21
R² = 0.9982
y = 3E-103x35.072
R² = 0.9979
MICROCONTROLLER SYSTEM

Local Display/User Interface
Graphic LCD
 Touch Screen Interface


What does this allow the user to do?
Directly view relevant information
 Calibrate probes and sensors
 Define parameters such as:

Pool Volume
 Pump Cycle Time

MICROCONTROLLER SYSTEM

Data to Web Server

Analog Level Created with:


PWM signals passed through a low pass filter
How does the Web Server Interpret Values?
Varying Duty Cycles Form Different Voltage Levels
 Communication Specification for Analog
Interpretation Defines Relationships

MICROCONTROLLER SYSTEM

Chemical Dispersal Control
Digital Control Logic (Stepper Motor Control)
 Solenoid Valve Channel Control


How the System Disperses the Chemicals
INSTRUMENTATION SETUP

Sensor Chamber Design
DISPENSER

Goal:


To create an interface that would utilize the
existing pool pump and filter system to dispense
and mix chemicals into the pool water.
Two distinct elements
Auger Based Dispenser
 Diverted Mixing Chamber

MECHANICAL SETUP

Final Mechanical Implementation
Pool
Dispenser
Sensor
Chamber
Pump
Filter
MECHANICAL SETUP

Dispenser System Design
MECHANICAL SETUP

Dispenser Prototype
WORKING COMPONENTS
DISPENSING CALIBRATION
Dispenser Output Mass vs. Auger Rotation
1000
900
y = 19.562250x
R² = 0.999996
Output Mass (grams)
800
700
600
500
Mass (g)
400
Linear (Mass (g))
300
200
100
0
0
5
10
15
20
25
Rotations
30
35
40
45
50
STEPPER MOTOR AND SOLENOID CONTROL
WIRELESS WEB SERVER

Goal:


To create a basic web server in order to
wirelessly broadcast system readings to the
consumer.
Main Components
802.11b Chip/Security Settings
 Analog Input/Calculations
 Website Design

WIRELESS WEB SERVER

802.11b Chip/Security Settings

Chip/Development Board Selection
Arduino Development Kit
 Wishield


Security Capabilities
Compatible with modern 802.11b/g routers
 Can utilize 64bit WEP, WPA, WPA2 encryption

WIRELESS WEB SERVER

Analog Input Calculations
Varying Duty Cycles + Low Pass Filter
 Analog Voltage 0V – 5V
 Communication Specification Determines pH, ORP,
Chemical Status, Temperature


Calculation of Free Chlorine
PWM
Low-Pass Filter
+
0-5 Volts Analog
WIRELESS WEB SERVER

Page Design
WIRELESS WEB SERVER

System Block Diagram
COMPETITIVE ANALYSIS

Main Competitors:
Chemtrol
 CAT
 Aquasol

Competitor’s
System
Features
Price
Chemtrol 250
pH and ORP Controller
$1995.00
CAT 4000
pH and ORP Controller + Web
Monitoring
$3650.00
Aquasol SPC
Controller
pH and ORP Controller
$2130.00
Chemtrol PC2000
pH, free Chlorine, Remote interface
$3150.00
SALES & MARKETING

Customer Base

Existing( US alone)
5.1 million in-ground pools
 3.7 million above-ground pools


Growth( Based on 2007)
131,000 new in-ground pools
 233,000 new above-ground pools


Target Demographic
Work with BUS 397 Advanced Marketing Class
 Middle-aged to Elderly in Average Middle to Upper
Middle Class Homes

GOING BEYOND

Different ways project could be enhanced or
developed further.






Expand Wireless Capability and Complexity
Add Online Data Logging
Add Wireless System Control
Use Precision Designed Mechanical Parts
Integrate onto single PCB
Develop Business Plan as a Distributer and/or a
Supplier
ACKNOWLEDGEMENTS
Tim Theriault– Industrial Consultant
 Prof. VanderLeest – Team Advisor
 Brian Honeck, Eric Walstra, Darryl DeBruin – CEAC
Reviewers
 Bob DeKraker – Parts Ordering
 Phil Jasperse – Shop Help

QUESTIONS