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Functional Specification Smart Irrigation System

Version Number: 97

Revision Date‐Time: 04/14/2014 12:20:00 PM

Development Project Lead: Valerie McManus

Peer Reviewer: Robert Strand

Assigned: SQA Engineer TBD

Business Analyst: TBD

Engineering Manager: Xu Han

Version Status Date Edited By Description of Change

1 Draft 04/14/2014 Jon Bebeau Compile individual works

Company Confidential This document contains confidential and proprietary information of EEL4901.901S14 – Smart Irrigation System Group. Any reproduction, disclosure, or use in whole or in part is expressly prohibited, except as may be specifically authorized by prior written agreement or permission.

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Table of Contents

1 OVERVIEW

1.1 Description

1.2 Scope

1.2.1 Objectives

1.2.2 Non-Objectives

1.3 References

2 FUNCTIONALITY

2.1 Existing Functionality Details

2.2 Proposed Design

2.2.1 Description of Functionality

2.2.2 User Interface Changes

2.2.3 External Interfaces

2.2.4 Process Flow

2.3 Alternate Design Options Considered

2.4 Design Decision Summary

3 CONSIDERATIONS

3.1 Dependencies and Assumptions

3.2 Risks

3.3 Managed Issues

4 SIGN-OFF

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1. Overview

The Smart Irrigation System (SIS) provides a complete water distribution, monitoring, and

control, and management system to optimize the effective use of water resources to irrigate

vegetation in a residential setting. Given the increasing environmental impact of water use for

irrigation coupled with the increasing expense of water resources and regulation, the Smart

Irrigation System leverages technology to effectively and efficiently provide the needed water

resources to the intended growth areas while providing accountability to the stakeholders. This

document outlines the specific components that embody the System, outlines how these

components interoperate and describes the functions, features and benefits of the Smart

Irrigation System.

1.1 Description

The Smart Irrigation System is positioned for the residential consumer market. The system can

be installed where an existing traditional irrigation systems exists, replacing several components

but utilizing many of existing components. The Smart Irrigation System can be the initial

installed watering system, or installed in combination with most existing systems providing a

modular growth path.

The Smart Irrigation System consists of several separate but cooperating components. A

network of in-ground, solar powered, wirelessly connected moisture sensors for a grid of the

property to measure soil moisture content and water (rain) fall. The density and distribution of

the moisture sensors vary according to the vegetation requirement. For example, grass may

need only a few sensors per irrigation zone. Flowering plants or vegetable gardens benefit from

a higher density of sensors to meet the irrigation plan of water distribution.

Periodically, each moisture sensor reports monitoring samples to a central hub, the Control

Point. The Control Point, not unlike traditional irrigation control units, is hub to receive wireless

sensor data and aggregate data. In addition, the Control Point contains the necessary circuitry,

power supplies, and switches to control and monitor solenoid valves for water distribution.

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Unlike traditional water control units, there are no displays, buttons, dials, switches (manual),

no user interaction occurs at the Control Point. Instead, a second wireless 802.11, compatible

with typical home wireless infrastructures, provides the link for user interaction. The Control

Point interfaces with the user over a hosted web server utilizing a web GUI for all Control Point

interaction.

The Control Point directs the operation of solenoid valves to direct water flow, monitors water

flow rates with fluid rate monitors, pressure sensors and provides external contacts to devices

such as well pumps, water retention pumps, and water level sensors where water cisterns are

employed.

The integration of moisture sensors network, water source selection control, and sensing with

an intuitive GUI interface provides for granular watering goals, cost effective resource

utilization, and scheduling as well as fault sensing, such as obstruction in the downstream

watering heads, high or low water pressures and alert messaging to report problems to the

system manager.

The benefit to the stakeholder is control of a scarce, increasingly expensive resource,

monitoring for system faults, like water line breaks, maintaining compliance with local

restriction and getting the most for the investment, not to mention a superior landscape.

1.2 Scope

For the purpose of this project, we elected to limit the development of several function and

features primarily to accommodate available time and resources. Yet, many features either

differentiate SIS from competition or provide benefits intrinsic to a new generation of irrigation

management. Features like multiple water sources, for instance, cistern storage or potable and

recycled water selection shall be deferred for future development. Still, references, where

appropriate, remain with the overall documentation to provide a point of departure for future

versions. Without scope restrictions, scope creep is likely endangering the timely completion of

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this project. The set of in-scope function and features are enumerated below along with

commentary explaining the decisions.

1. Target market simplification.

a. Residential properties under two acres. This area restriction relates to the

wireless portion of the moisture sensors, specifically to need to propagate RF

signals emanating from the moisture sensor at near ground level to a receive

(Control Point) mounted in a central location. The concern is available RF power,

antenna gain and most importantly obstruction to line-of-site.

b. The concept of in-ground, controlled, residential irrigation is well known and

understood as common knowledge. This reduces the barrier to entry.

2. Wireless range of 150 meters. The least understood technology is low power RF

communication of practical digital communication. Correspondingly, the wireless

communication between the moisture sensor and Control Point is likely the most

challenging design component. Limiting the range provides the best opportunity for

success.

3. Up to 8 zones. A zone is a collection of watering discharge heads (Heads) (sprinklers,

drip lines) connected and controlled by a single valve. All Heads are active when their

zone is activated.

4. Up to 32 wireless moisture sensors.

5. Installation into an existing in-ground, traditional irrigation system.

a. The initial prototype shall be installed overlaying an existing, traditional in-

ground irrigation system. This restriction is simply to minimize the cost and time

requires to install and demonstrate the SIS.

b. Only the in-ground system, not potted plants or above ground utility will be

supported.

6. Control Point requires 120V 2A utility power.

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7. Compatible off the shelf components. To minimize the need for newly created

components, we plan to leverage the existing body of readily complementary plumbing

and irrigation components:

a. Common facilities, ¾ PCV piping, valves, utility water supplies, both potable and

recycled water, availability or complementary components, valves, solenoid

valves, PVC pipe and fittings, various sprinkler heads, drip lines, spray nozzles,

tools, supplies.

b. Importantly, a body of common knowledge and readily available tutorials for the

common homeowner.

8. Web Based GUI to configure, monitor and control the SIS.

a. Create watering schedules.

b. Create allowable watering dates/times.

c. Design watering budgets and watering goals.

d. Prioritize resource consumption budget.

e. Generate alert messages.

Other features or stubs to support future development, exist and documented in Section 1.2.2,

Non-Objectives.

1.2.1 Objectives

Background

The goal is an environmentally sensitive optimization of water allocation, while recognizing the

need for irrigation both for esthetic and commercial values while nurturing the landscape

investment.

Many inventions are born from experience. The Smart Irrigation System also has its roots in

personal experience. Several of the features embodied in the design resulted from failures with

an existing residential irrigation systems. This traditionally employs a controller, solenoid water

valves and electronic control unit, all quality components for leading manufacture.

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Aside from the normal, annoying clogged sprinkler heads, occasional broken water control

valves and arcane control unit “programming” method, a $1,200 water bill for one month

forced the issue of system supervision.

In the instant case, the lawn service uses a commercial riding lawn mower. Due to wet

conditions the ground became unusually soft. The weight of the equipment cracked the city's

main water feed pipe to the irrigation system. Later the pipe burst. The obscured location of

the burst and heavy foliage cover prevented observation of running water. The runoff drained

to a stormwater system and remained unnoticed for over a month.

A series of obvious needs arose. How could it have been prevented? Or, more to the point, how

could it have been detected and remedied quickly. After researching my options, additional

shortcomings of the prototypical residential irrigation systems emerged. At present there is not

an existing residential system that meets these needs; hence a suitable Professional Design

Project emerged. Necessity is, aptly, the mother of invention. Additional functions and features

not part of the project but none the less important, have been summarized in next section.

Here, we prioritize and outline the specific features and functions addressed by the SIS system.

Monitoring

Existing commercial offerings provide little to no monitoring or supervision. From the

background, the feature to detect and report a critical issue like broken water main is

paramount in the design. Monitoring is divided into two areas; (1) fault detection and alert

notification and (2) monitoring of normal daily usage and comparison to expected or defined

irrigation goals.

Fault detection

Obviously, a broken water main is an emergency, both in terms of cost and wasted resources.

During the analysis, additional fault detection features presented themselves.

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● Detect changes in water volume to each zone. Characterizing normal operation of each

zone provided the basis for analysis of variance to a norm. Here, unpressurized (zone)

pipe breaks can be detected.

● Using the same method, clogged or faulty sprinkler heads are identified.

● Electrical faults of the solenoid (valves) can be detected and reported.

● Pressures, or deviation from expected pressures for both operation and standby indicate

a fault

Optimization and Cost Containment

Water budgets and goal oriented zone management is not available in the residential market.

Here SIS matches the owner defined moisture goals with financial implication to obtain the

goals and where conflict exists, how allocation will be brokered. During a drought and when a

monthly water cost is established, when water budget is over allocated, SIS will defer or reduce

irrigating some zones in favor of higher priority zones. For example, reduce watering grass in

favor of vegetables.

Utilization

Everyone has witnessed active irrigation during a downpour. Many municipalities require a

“rain sensor” to inhibit sprinkling during or immediately after rain. Commercial rain sensors are

in wanting. When operable, the amount of rain is uncorrelated to the desired moisture goals.

The SIS architects Goal-Based Active Monitoring. Here, the owner specifies the target moisture

per zone and the criteria to meet that ground moisture goal.

Set and Forget

The SIS is configured using a web-based GUI with contemporary 3D view of the property,

location of sensors, mapping of ground areas by moisture goal and procedures to insure

watering where need and when need. All accounting for local restrictions, watering cycles and

water cost budget.

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The Set and Forget objective also provided feedback. The user can receive notices of goal

failure. Perhaps the target ground moisture is not obtainable given the configured constraints.

A warning can be generated.

Target Market

The target customer is residential homeowners with existing in-ground central irrigation

systems. This leverages the sunk cost of installed piping, heads and control valve. Utilizing

portions of the existing infrastructure provides new features with minimally invasive to existing

infrastructure.

1.2.2 Non-Objectives During the design sessions, many features were discussed. For scope feasibility reasons, several

meritorious features or option became relegated as not essential for an initial offering and

removed from scope.

1. Support multiple water sources. The SIS implement one water source, public utility

water. However many water sources may be available. Supporting each or more

importantly, supporting several concurrent sources provide a robust and cost effective

gradient. Other sources include:

a. Well water

b. Recycled water

c. Cistern or collected “rain” water.

d. Natural reservoir, like pond, lake, storm water reclamation.

Each provide additional sources and each has unique implementation and equipment needs.

For example, well water requires operating well pump control and pressure monitoring sensor.

Reclaimed water provide lower cost source but may not be suitable for irrigating human

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consumable products like fruit and vegetables. There may be the need to purge lines between

types of water source utilization.

2. Commercial Use. Golf courses, apartment complexes, public areas, all are candidates for

SIS, however the scale and complexity are beyond the scope. Additionally, high water users

often have installed sophisticated irrigations systems and dedicated grounds staff. Golf

courses often implement satellite communication to monitor and control irrigation.

3. Geographic limitation. A novel feature of SIS is multiple in-ground sensors. Each reports

sensor information to the central Control Point. Each transmits only “in the blind” with

receiving responses. This primarily for cost containment. The ability to reliably

communicate with the Control Point with low power, from in-ground or near to the ground

antenna proves challenging. By limit the distance between transmitter (in-ground sensor)

and receiver (Control Point), we limit the design risk.

4. Standard protocol. The design calls for sensor payloads unrelated to any standard.

Providing or adopting a standard would provide interoperability, not currently a priority.

The Control Point to user LAN over 802.11 (Wi-Fi) will necessarily follow the standard.

5. Fixed and minimal number of sensor control. Initially, the prototype is limited to 8 valve

control switches. The design contemplated an initial fixed set of 8 with optional modules up

to 24 zones. For simplicity and proof of concept, supporting 8 zones appears sufficient.

1.3 References

● Controller Homeowner’s Guide by Smart Modular ● http://www.rainbird.com/documents/turf/man_ESP-SMTe_EN.pdf

● Quick-Start Installation and Setup Guide by Smart Modular ● http://www.rainbird.com/documents/turf/man_ESP-SMTe_QuickStart_EN.pdf

● Soil Sensor Basic Manual by Precision ● http://media.toro.com/CatalogDocuments/Manual/pss_basicmanual.pdf

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● Quick-Start Guide by Rainbird ● www.rainbird.com/documents/.../man_SSTsmart-QuickStartGuide.pdf

● User Manual by Rainbird ● www.rainbird.com/landscape/support/controllers.htm

● Commercial Products Catalog by Rainbird ● http://www.rainbird.com/documents/diy/DIYCatalog2010.pdf

● Precision Soil Sensor by Toro ● http://www.toro.com/en-us/homeowner/professional-

irrigation/sensors/pages/model.aspx?pid=precision-soil-sensor

● Rain Sensor by Toro ● http://www.caddetails.com/redirectLogins/ManufacFrame/browse.asp?cid=065

● Residential/Commercial Irrigation Specification Catalog by Toro ● http://www.caddetails.com/redirectLogins/ManufacFrame/browse.asp?cid=065

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2 Functionality

The Smart Irrigation System is designed to supplant currently installed in-ground central

irrigation systems offering improved control, supervision, monitoring and performance feedback

using a web-based GUI. The SIS provides functionality beyond existing systems. The functions

include a browser-based (Java) setup and configuration exploiting the now ubiquitous web

interface.

A residential client would purchase a kit from the local “box store”, like Lowes or Home Depot.

The kit consistent of 10-20 in-ground, wireless, solar powered moisture sensors and a Central

Control unit. The Central Control unit replaces an existing, competitive “dumb” control unit

utilizing existing utility power and providing the same switching to control existing solenoid

controlled water valves. The SIS reuses the existing in-ground pipe and sprinkler heads.

The SIS is designed for non-technical installation by the owner, lawn maintenance staff or

professional residential irrigation installers.

A major departure from existing dumb systems is the in-ground sensor array. Provided are a

number of sensors. Based on the topology of the property, the location, size and moisture

sensitivity of each watering zone, the installer planes a number of sensors distributed within the

watering zone to monitor the ground moisture content. The location and density of sensors is

dictated by the type and importance of moisture to the vegetation contained within each zone.

The installer sets the sensor, a one foot long, 3/4 inch diameter tube with a small cylindrical cap.

The sensors are inserted into the ground so the cap meets the surrounding elevation. For grass,

this is below mowing height. For non-mowed areas, this is grade. The sensor is turned to point

to the wall mounted Control Point. A large molded arrow clearly visible on the cap provides

orientation. The installer notes the approximate location each sensor and its unique ID.

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Once all sensors are installed and the Control Point has replaced the existing controller, the

system is ready for initial configuration. The user connects to the SIS Control Point using their

favorite browser. The user is prompted for security credentials and authenticated.

The important configuration information is the location of the installed sensors, the location of

watering zones. The user enters a block diagram of the property using a draw interface. Once

the property outline is completed, existing water zones are overlaid with the approximate

location of the sensors. This creates a mapping of watering zones to sensors. Then, the user

creates watering goals. Using drag and drop, drop-down windows and text entry, the user

specifies the watering schedules, time of day and day of week. Lastly, the user specifies the

priority and moisture objectives by zone. SIS provides a list of typical vegetation by common

name. The user selects a variety. This data relates to internal tables which map the collected

sensor data representing current area moisture content to the optimal. This SIS schedules

dispensing of water based on the goal, need, schedule and cost budget.

Ongoing status information is shown graphically graphically, coloring each zone to represent

the current and goal moisture content, water budget and historical utilization, rainfall detected

and its impact on goals.

2.1 Existing Functionality Details No existing implementation exists. The Smart Irrigation System is an entirely new product.

However, as reference, a brief review of competitive products will provide a background and

comparison for several of the following sections.

The industry standard residential system consists of:

1) An electronic control unit. This unit is housed in a plastic box mounted to an outside

wall of the residence. A 120V AC power is required. This unit consists of interface

circuits, typically a rotary selector knob and a few switches. Most units contain a basic 4

digit display. Here the user “programs” the unit using codes, button sequences. Newer

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units interface to solenoid control valves with 24V using SCRs. Older units use contact

relays.

2) In-ground solenoid controlled water valves. Each valve operates a “zone”. A zone is a

set of sprinkler heads, drip lines, sprayers (Heads) or some combination thereof, all

operate in unison. Energizing the solenoid opens the water valve, dispensing water to all

Heads. The control unit opens and closes valves based on a predefined schedule

obeying a calendar. Typical ON times per zone range from 10 to 60 minutes.

One residential unit consists of a single moisture sensor, wirelessly transmitting to a companion

control unit. 900 MHz in the ISM band is utilized (same as the older wireless home home)

primarily to superior RF signal propagation characteristic and the availability of low cost RF

chips. Here, one sensor controls one zone. This is characterized as an extension of the existing

“dumb” systems and not an integrated, goal oriented system proposed.

2.2 Proposed Design The Smart Irrigation System (SIS) consists for the following major components. The high-level

functions are described here and references to other section of this document, notably Section

1.2.1 objectives, are incorporated by reference.

Major SIS components:

● Moisture Sensors. In-ground, wireless, solar powered, moisture sensors. The sensor is a

one foot long, ¾ inch diameter sensor/processor/transmitter. The sensor periodically,

perhaps every 6 minutes, senses the moisture content surrounding the sensor. The

readings are stored locally. Periodically, perhaps every 4 hours, the sensor reports the

current set of data to the Control Point. Several sensors, installed within a user defined

area (zone) for a grid over an area of like characteristic. A sensor grid is related to

existing or proposed water sprinkler zones or an area of like vegetation, for example,

grass areas or flower or rows of vegetables.

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● Control Point. A device enclosure, mounted (typically) to an exterior wall, containing the

majority of electronic processing, solid-state switches to actuate solenoid water control

valves. Control Point is the receiver of messages sent by the sensor network. Messages

are decoded, validated and resulting sensor readings are logged to internal memory.

Each sensor is serialized providing a unique identification. The location of each sensor is

defined during the installation or subsequent system modification. The control point

maintains a recent database of historical sensor information. This information is

processed to determine current, short term and long term trends of soil moisture

content. Based upon watering goals and water budget defined by the user, the moisture

trends, and zone objectives and allowed watering schedules, SIS will schedule watering

events to control the rate of watering, areas (zones) to be watered, duration and time of

day to perform watering. Sensors then indirectly report the effectiveness of these

targeted watering events. Rain or other moisture modification events (high humidity) is

indirectly sensed by the moisture sensors and the effects are automatically incorporated

to target scheduling.

Physical design, functions, features and benefits are described in section contained herein.

Below is pro forma bill of materials prep presents a high level costs. Actual components,

especially electronic circuit components, remain fluid pending power budget considerations of

microprocessor selection and RF duty cycle and emitted power.

Sensor BOM The design proposes a minimum of eight (8) sensors. More sensors will be available in kits of 4

each. The system will accommodate a total of 64 sensors. The capital expense is a one-time

charge for manufacturing of injection molds.

Costs calculated at 10,000 unit prices

Sensor BOM pro forma Cost ABS injection molding barrel 1.02

ABS injection molding Cap 0.97 Solar cell 0.30

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Stainless steel dipole antenna 0.27

Sensor stainless steel external strips 0.45 Hall effect maintenance switch 0.28 Antenna spade connectors 0.24

PCB 2 layer 1.20 RF Transmitter chip (910 MHz) 1.02

microprocessor 2.20 power and charging control 1.10 Super CAP 1.20

Sensor A/D convertor 0.50 Assembly labor 2.00

TOTAL 12.75

Capital One-Time Costs (OTC) Injection molds

Barrel 40,000.00 Cap 25,000.00

Control Point BOM Each installation requires one (1) control unit to manage up to 64 sensors. However,

Costs calculated at 10,000 unit prices

Control Point pro forma Cost Polystyrene case 3.75

900 MHz antenna 2.20 2.4 GHz antenna 2.50 PCB 2 layer 5.25

Processor 6.90 AC power controller 2.25 DC power supply (50 mA) 2.75

900 MHz radio 9.00 2.4 GHz radio 11.00

Device SCR (8 ext interface) SubAsy 2.20 power and charging control 9.00 Li backup battery 1.20

8 LED 0.32 2 x 16 LCD 4.00

TOTAL 62.32

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Notes

The above projections are based in published product list from DigiKey for volume at 10,000

parts. The exact part selection must be deferred until testing of a prototype. The RF section is

the most critical and extensive tests are required.

A microprocessor offering extremely low power consumption in sleep mode is required due

primarily to solar power. The sleep mode must be timer interruptible (wake up) and commune

on the order of micro Amps while asleep.

Fabrication and assembly costs remain undetermined.

Packaging costs depend on productizing, market research and branding.

2.2.1 Description of Functionality The function set is selected to leverage technology to enhance the effectiveness of applying an

expensive resource to property. The goal is not just put water on the lawn for x min, or until

this one sensor thinks it’s enough, but balancing need with cost, to optimize the entire system.

Here we integrate new and powerful technology of moisture content feedback with an

integrated goal oriented water management system. The customer can realize lower,

predictable operating costs, utilize the water resource most efficiently and effectively and

identify faults or sub-optimal operation.

2.2.2 User Interface Changes N/A 2.2.3 External Interfaces SIS is architected addresses two existing environments: (1) a new irrigation system and (2)

displacement of existing in-ground irrigation systems.

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New Installation. Where no irrigation system exists or where any existing components will be

abandon, the process is simple. SIS will provide the required components in kit form and/or as

individual add-on components.

Replacement. To lower the barrier to entry, SIS is designed as a functional replacement for

existing dumb control units. This simplifies the time, cost and complexity by swapping control

units and reusing existing piping and solenoid valves. Design consideration include field-

installable modules that control external devices (solenoids). This allows the vendor specific

interface specification and minimal cost.

2.2.4 Process Flow 2.3 Alternate Design Options Considered

Many, many alternatives remain. The prime motivator in selection the features and

implementation is to minimize risk and guard against scope creep. In addition to the design

proposed, our system had alternative designs which are now left as possible additions to our

system in the future. These designs were not chosen to be a part of the initial design due to

the need for simplification.

● One alternative component to our system is the option of other sources of water to the

system, such as rainwater, recycled water, or even options to fertilize the landscape.

● Optional component includes add-ons to the user interface webpage. These can be

additional plots of data, additional alerts to the user, ways to organize and design a

landscape, etc. These, in turn, will require additional controls of the controller, and may

even require additional data from the sensor system.

● Add pressure sensors which will sense unusual activity on the water line. We can add a

component which analyzes the weather and decides whether the plants need to be

watered or not.

● The need or support of multiple Control Points. The concern is RF signal reception from

the sensors to the Control Point. Some number of sensors will be out of line of sight to

the Control Point. Consider sensors on “the other side of the house”. Clearly not line of

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sight here. The expectation that 900 MHz will provide adequate signal reception

removing the need for a second Control Point or repeater.

● We considered wired moisture sensors. This would remove the need for 900 MHz

wireless and power could be supplied over the wire. This was quickly rejected due the

cost, complexity and reliability of installing new wire to an existing infrastructure.

● Batteries in lieu of solar power. The need to maintain batteries, keep the unit free of

contamination and real or perceived need to periodically change in-ground unit batteries

prompted the desire for a maintenance-free implementation. We view this feature as a

marketing point as much as a technical issue.

● User interface is expected to be with a customer provided web browser (PC) utilizing an

existing Wi-Fi network. Some thought was given to developing a stand-alone Windows

or Mac application or Smart-phone app, however, selection of the Java based web

browser implementation allows platform independence.

2.4 Design Decision Summary Selection of a design platform, the choice to target existing in-ground “dumb” irrigation systems

is primarily to gain market acceptance. The design consideration focus on providing features

not available in the residential market. The aim is mid to upper income, single family residences

where significant investments in landscaping exist. The proposed function, features and

benefits offer compelling advantages in ecological optimization of expensive and increasingly

scarce water resources, provide the best application of the resources. Integrated monitoring

and budgeting allows the owner to decide, control and monitor irrigation activities and results

in technical and financial terms.

3 Considerations 3.1 Dependencies and Assumptions

We assume:

● Installation instructions and the ability of the typical consumer, owner or installer, is

sufficient to ensure proper placement, connection and configuration of the system.

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● That users are sufficient technically capable to configure a secure wireless link between

their web browser and the Control Point.

3.2 Risks

Risks abound. Currently, no critical risks exist. Yet, many potential risks must be addressed

during prototype. A summary of identified concerns or risks include:

● Radio wave propagation. This is the top priority concern. The design calls for extremely

low power FM at 900 MHz for the in-ground sensor to the Control Point. Generally, the

channel will NOT be line of sight. Further, the dipole antenna is effectively at ground

level and obstruction are expected; mostly vegetation. Other propagation impediment

include signal attenuation through buildings, trees, other structures. Lastly, we designed

for 200 meter line- of sight. Improper installation of the in-ground sensors, for example

greater than 200 meters may pose operational problems.

● Compatibility with existing equipment. The design expects 24V AC solenoids. Some

systems may use other voltages or currents outside SIS capability.

● SIS expects a use provided Wi-Fi network, incompatibilities, signal range concerns and

signal strength for the users’ workstation to the Control Point remain a concern.

● Network security to prevent accidental or intentional interference remain an unresolved

issue. The prototype will ignore these concerns.

● Transmit only architecture. For cost containment reasons, the sensor network is a

transmit-only architecture. There is no method to verify receipt of information or

control and update the in-ground sensors. The wisdom of this unidirectional

information transfer should be reviewed.

● Price point remains unknown. The market research determining MSRP remain. While

the intent is for larger residential properties where significant investment in landscape

exists, the appetite for retail price remains unknown.

● Reliability of in-ground sensors. The device is exposed to all the elements often

submerged in moist soil, exposed to sun, chemicals, fertilizers and physical contact from

workers and lawn maintenance. Selection and testing of robust materials remain.

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3.3 Managed Issues

The design has completed the initial design. Specific design criteria, like Bill of Materials,

specific materials, electronic components, packaging, and all prerequisites prior to proof-of-

concept modeling remain. All Issues to date are considered concept refinement. Consequently

for formal incident, change control or change management in place. At the moment, none is

needed.

4 Sign-off Development Representative TBD

Development Manager TBD

Quality Assurance Representative TBD

Business Development Rep TBD

Director of Technology TBD