# 1 Introduction

## 1.1 Purpose

This Software Requirements Specification (SRS) defines the requirements for the prototype “Smart House” software system named DigitalHome (DH), developed by the DigitalHomeOwner Division of HomeOwner Inc. It specifies the capabilities needed to monitor and control home environmental conditions (temperature, humidity, lighting, small appliances) and security, via a web interface, operating in a simulated environment to inform future business decisions for potential commercialization.

## 1.2 Scope

- Product name: DigitalHome (DH) prototype smart home management system.
- What the software will do:
  - Provide monitoring and control of temperature, humidity, lighting, small appliances, and security contacts.
  - Support user account management, configuration, planning/scheduling, and reporting.
  - Communicate with simulated sensors and controllers via a simulated DH gateway using wireless signals.
- Application, benefits, objectives, goals:
  - Application: Home environmental and security management accessible remotely via web-ready devices.
  - Benefits: Improved convenience, safety, and energy/environmental management.
  - Objectives: Demonstrate feasibility (“proof of concept”) and provide a basis for business decisions on a commercial product.
- Consistency: This SRS is aligned with the Digital Home High Level Requirements Definition [HLRD 2010] and the Digital Home Use Case Model [HO2010].

## 1.3 Product overview

### 1.3.1 Product perspective

DigitalHome is a home management software system interfacing with a set of household devices (thermostats, humidistats, contact sensors, alarms, power switches), a home wireless gateway, and a home web server. For this prototype, all devices and the environment are simulated. The DH web server provides user access via web-ready devices and communicates with home devices through the DH gateway.

#### System interfaces

- DH web server to DH gateway device for command and telemetry exchange.
- DH gateway to simulated sensors and controllers via wireless RF.
- User web portal to DH web server for monitoring, control, planning, reporting, and account management.
- Backup and recovery interface for system data (configuration, defaults, plans, usage).
- Optional local home web server hosted on a home computer providing:
  - Device interaction and control
  - Storage for plans and home database
  - User account administration
  - Backup services

#### User interfaces

- Web-based interface accessible via web-ready computers, cell phones, and PDAs for:
  - Login/logout and account access
  - Viewing and changing environmental parameters
  - Scheduling via monthly planner
  - Viewing reports
  - Accessing online documentation (including FAQs)
- Clear, descriptive user-visible error/exception messages are required.

#### Hardware interfaces

- DH gateway device:
  - Connects to a broadband Internet connection.
  - Includes an RF module for wireless communications with sensors/controllers.
  - Operates up to a 1000-foot indoor transmission range.
- Supported device types (simulated in prototype):
  - Programmable thermostats (temperature sensor/controller)
  - Programmable humidistats (humidity sensor/controller)
  - Magnetic door/window contact sensors
  - Security sound and light alarms
  - Programmable power switches (115V, 10A)

#### Software interfaces

- Security protocols: Transport Layer Security (TLS) for authentication and encryption during web access.
- [N/A] for specific OS, database engine, or third-party application system interfaces (not specified in the original SRS).

#### Communications interfaces

- Internet connectivity via an ISP (e.g., cable modem, high-speed DSL).
- Wireless RF communication between the DH gateway and home devices.
- Web communication between user devices and the DH web server.

#### Memory constraints

- [N/A]

#### Operations

- Normal operations:
  - User-initiated monitoring and control via web portal.
  - Scheduled unattended operations via monthly planner.
  - Periodic sensor data acquisition and display refresh.
- Support functions:
  - Data backup daily at a time set by the DH Technician.
  - Recovery restores from most recent backup after failure.
- Exception handling:
  - Clear, descriptive messages for errors and exceptional conditions.

#### Site adaptation requirements

- Technician-configurable:
  - System parameters and defaults
  - User accounts
  - Backup schedule
- Home configuration:
  - Up to 8 thermostats and up to 8 humidistats in rooms/spaces
  - Up to 50 contact sensors on doors/windows
  - Up to 100 power switches for small appliances and lighting
- Optional deployment choice between hosted DH web server and local home server.

#### Interfaces with services

- ISP providing broadband Internet connectivity.
- [N/A] for cloud/SaaS dependencies beyond general web hosting.

### 1.3.2 Product functions

- Environmental monitoring and control:
  - Temperature: read/set per thermostat; scheduling; Fahrenheit/Celsius support.
  - Humidity: read/set per humidistat; scheduling.
- Security:
  - Manage door/window contact sensors.
  - Activate sound and light alarms on security breach.
- Appliance and lighting management:
  - Read and change ON/OFF state via power switches.
- Planning:
  - Monthly planner supporting up to four daily periods per day to set environmental parameters and device states.
  - User overrides via web or device manual controls (persisting until the next planned/default period).
- Reporting:
  - Monthly reports for the past two years including temperature/humidity statistics and security breach events, and system downtime periods.
- System management:
  - User account administration (login with account name and password).
  - Technician/Master User configuration of system parameters and accounts.
  - Backup and recovery of system data.

### 1.3.3 User characteristics

- General user:
  - Familiar with their home layout and device locations.
  - Able to use web interfaces for login, navigation, and form submissions.
- Master user:
  - Same rights as a DH Technician for configuration tasks (e.g., adding accounts, changing defaults).
- DH Technician:
  - Experienced with relevant hardware, software, and web services.
  - Trained by DigitalHomeOwner on DH functionality, architecture, and operations.
  - Authorized to set system parameters, establish accounts, and start/stop the system.

### 1.3.4 Limitations

- Prototype constraints:
  - Initial version is a limited prototype; not a complete specification for a commercial product.
  - Entirely simulated environment; no physical home, sensors, or controllers.
- Operational constraints:
  - Requires an ISP and broadband Internet connection.
  - Wireless communication range up to 1000 feet indoors.
- Capacity constraints:
  - Up to 8 thermostats and 8 humidistats, 50 contact sensors, and 100 power switches.
- Standards and policies:
  - HVAC compatibility per ASHRAE standards/policies/procedures.
  - Security via recognized protocols (e.g., TLS).
- Reliability and safety:
  - High reliability required; potential safety impacts if failures occur (security breaches, inadequate lighting, inappropriate environmental conditions).
- Project constraints:
  - Twelve-month completion target with a small team and cost minimization for elements.
  - Use widely accepted, available technologies and standards where possible.

## 1.4 Definitions

- ASHRAE: American Society of Heating, Refrigerating and Air-Conditioning Engineers.
- Authentication: Process verifying a user’s claimed identity, typically via username and password.
- Broadband Internet: High data rate Internet access contrasted with dial-up.
- DH (Digital Home): Name of the prototype smart home product produced by DigitalHomeOwner.
- DigitalHomeOwner: Division of HomeOwner Inc. responsible for producing DigitalHome products.
- DSL (Digital Subscriber Line): Technology for digital data transmission over local telephone network wires.
- Encryption: Transforming information into ciphertext to make it unreadable without a key.
- FAQ: Frequently asked questions.
- Gateway Device: Home networking device connecting in-home devices to the Internet/WAN.
- HomeOwner Inc.: National retail chain serving home owners in building, furnishing, repairing, and improving homes.
- HVAC: Heating, Ventilation and Air Conditioning.
- Humidistat: Instrument that measures and controls relative humidity.
- ISP: Internet Service Provider.
- PDA: Personal Digital Assistant.
- RF: Radio Frequency.
- Security breach: An external act that bypasses or contravenes the digital home security system (e.g., door opened when contact sensor is active).
- Set point: Numeric value establishing a desired environmental quantity (e.g., temperature 70°F).
- SRS: Software Requirements Specification.
- Transport Layer Security (TLS): Cryptographic protocols providing security for network communications.

# 2 References

- Compliance
  - [ASHRAE 2010] American Society of Heating, Refrigerating and Air-Conditioning Engineers, http://www.ashrae.org/ (accessed October 2010).
  - [IEEE830] IEEE Std 830-1998, IEEE Recommended Practice for Software Requirements Specifications, IEEE, 1998.
  - [IEEE 1008] ANSI/IEEE Std 1008-1987, IEEE Standard for Software Unit Testing, IEEE, 1987.
  - [IEEE 1012] IEEE Std 1012-2004, IEEE Standard for Software Verification and Validation, IEEE, 2004.
  - [IEEE1016] IEEE Std 1016-2009, IEEE Standard for Information Technology - Systems Design - Software Design Descriptions, IEEE, 2009.
  - [IEEE1028] IEEE Std 1028-2008, IEEE Standard for Software Reviews and Audits, IEEE, 2008.
  - [HO4710] Kramer, S., HomeOwner Coding Standard, HO4710, Homeowner Inc., August 2009.
  - [HO2305] Sykes, J., and Rook, R., Guidelines for Developing HomeOwner Technical Reports, HO2305, Homeowner Inc., March 2002.
- Guidance
  - [HLRD 2010] DigitalHomeOwner Division, Digital Home High Level Requirements Definition, Homeowner Inc., September 2010.
  - [HO2010] Digital Home Use Case Model, HomeOwner Inc., DigitalHomeOwner Division, October 24, 2010.
  - [Meyer 2004] Meyer, G., Smart Home Hacks: Tips & Tools for Automating Your House, O’Reilly, 2004.

# 3 Requirements

## 3.1 Functions

- General system
  - DH shall allow a web-ready computer, cell phone, or PDA to monitor and control home temperature, humidity, lighting, security contacts, and small appliance state via the DH web server.
  - The DH web server shall be the communication center through which users monitor and control devices.
  - A DH gateway shall connect to the home’s broadband Internet connection and use wireless communications to exchange data with devices.
  - Sensor values shall be read via wireless communication and saved to the home database; controller values shall be sent to change device states.
  - Exception handling shall provide clear, descriptive user messages upon errors or exceptional conditions.
- Temperature control (thermostats)
  - Up to 8 thermostats shall be supported, each in a single enclosed space.
  - Users shall read current temperature at each thermostat.
  - Users shall set thermostat temperatures between 60°F and 80°F inclusive, in 1° increments.
  - Temperature units shall support Fahrenheit and Celsius.
  - Thermostats may be controlled individually or collectively for zoned control.
  - Scheduling: For each thermostat, up to 24 one-hour settings per day for each day of the week shall be schedulable.
  - Manual override: A manual setting shall remain in effect until the end of the current planned/default time period, after which planned/default settings resume.
  - Thermostats shall communicate wirelessly with the master control unit (gateway).
  - Compatibility: DH shall be compatible with centralized HVAC systems (gas, oil, electricity, solar, or combinations) and adhere to ASHRAE standards, policies, and procedures.
- Humidity control (humidistats)
  - Up to 8 humidistats shall be supported, each in a single enclosed space.
  - Users shall read current humidity at each humidistat.
  - Users shall set humidity between 30% and 60% inclusive, in 1% increments.
  - Scheduling: For each humidistat, up to 24 one-hour settings per day for each day of the week shall be schedulable.
  - Manual override: A manual setting shall remain in effect until the end of the current planned/default time period, after which planned/default settings resume.
  - Humidistats shall communicate via wireless signals through the master control unit.
- Security
  - DH shall manage up to 50 door/window contact sensors.
  - DH shall activate both sound and light alarm subsystems (one sound alarm and one light alarm subsystem with multiple lights) upon a security breach (contact sensor set OPEN).
- Appliance and lighting management
  - DH shall manage up to 100 power switches (115V, 10A).
  - DH shall report the state of a power switch (OFF/ON) indicating appliance state.
  - DH shall change a power switch state (OFF to ON or ON to OFF), thereby changing appliance state.
  - Manual override: If a user changes a power switch state manually, it shall remain until the end of the current planned/default period, after which planned/default settings resume.
- Planning
  - Monthly planner shall allow creation/modification of a plan for a given month/year specifying, for each day, up to four daily time periods and associated parameter settings (temperature, humidity, contact sensors, and power switch states).
  - Users may override planned values via the website or manual device switches.
- Reporting
  - For any month/year in the past two years, DH shall provide a month report including:
    - Daily average, maximum (with time), and minimum (with time) temperature for each thermostat and humidity for each humidistat.
    - Day/time of any security breaches (alarm activations).
    - Periods when the DH system was not in operation.
- Accounts and security
  - User accounts shall be established upon installation.
  - Login shall require account name and password.
  - Authentication and encryption shall use recognized reliable, effective security technology (e.g., TLS).

## 3.2 Performance requirements

- Displays of environmental conditions (temperature, humidity, contact sensors, power switches) shall update at least every 2 seconds.
- Sensor data acquisition (temperature, humidity, contact, power state) shall be at a minimum rate of 10 Hz.
- Sensor/controller devices shall be within 1000 feet of the master control device (gateway) to communicate.
- Capacity:
  - Up to 8 thermostats and 8 humidistats.
  - Up to 50 contact sensors.
  - Up to 100 power switches.

## 3.3 Usability requirements

- Web access via common web-ready devices (computers, cell phones, PDAs).
- Online user documentation shall be provided, including:
  - FAQs (e.g., changing passwords, obtaining support).
  - Explanations of parameter settings and sensor value readings, including limitations and accuracy constraints.
  - Instructions for using the DH Planner.
- Measurable usability metrics (e.g., task completion times, error rates): [N/A]

## 3.5 Logical database requirements

- Information types:
  - User accounts, configuration, default parameter settings.
  - Device inventories (thermostats, humidistats, contacts, power switches) and locations.
  - Sensor readings (temperature, humidity, contact states, power states).
  - Schedules/plans (daily and monthly).
  - Usage and operational status data (uptime/downtime).
  - Security events (breach timestamps).
- Frequency of use:
  - Sensor readings acquired at least 10 Hz; displays updated at least every 2 seconds.
  - Daily backups of all system data.
- Accessing capabilities:
  - Web interface for reading and updating settings, schedules, and reports.
  - Technician interface for configuration and backup scheduling.
- Data relationships:
  - Devices associated with rooms/spaces.
  - Plans linked to days and time periods; parameters linked to devices/zones.
  - Sensor readings linked to devices with timestamps.
  - Security events linked to contact sensors with timestamps.
- Integrity constraints:
  - Temperature set points limited to 60–80°F (inclusive) in 1° increments.
  - Humidity set points limited to 30–60% (inclusive) in 1% increments.
  - Device counts limited to stated capacities.
- Security:
  - Authentication required for access; data transmissions protected with TLS.
- Retention:
  - Reporting requires retention sufficient to produce monthly reports for the past two years.

## 3.6 Design constraints

- Development constraints:
  - Prototype version to be completed within twelve months of inception by a five-engineer team.
  - Use the development process specified by DigitalHomeOwner Inc.
  - Employ widely used, accepted, and available hardware/software technologies and standards where possible.
  - Minimize costs of DH elements; document cost-minimization efforts and price comparisons.
  - Major changes to requirements must be approved by the Director of the DigitalHomeOwner Division.
- Operational environment constraints:
  - Requires an ISP with broadband connectivity (e.g., cable, high-speed DSL).
  - Wireless RF communication via DH gateway; 1000-foot indoor range.
- Standards and methods:
  - HVAC compatibility per ASHRAE standards/policies/procedures.
  - Use of IEEE standards [IEEE830, IEEE1008, IEEE1016, IEEE1028] and HomeOwner Coding Standard [HO4710].
  - Object-oriented development using UML 2.0 is preferred; exceptions require CIO approval.

## 3.7 Software system attributes

- Reliability:
  - No more than 1 failure per 10,000 hours of operation.
- Availability:
  - Daily backups of system data at a technician-set time.
  - Recovery shall restore configuration, defaults, planning, and usage data from the most recent backup after failures (power loss, Internet loss, software/hardware failures).
- Security:
  - User authentication with account name and password.
  - Use TLS or equivalent for authentication and encryption.
  - Clear error messages without leaking sensitive information.
- Maintainability:
  - Documentation of requirements, design, and code.
  - Use of abstraction, information hiding, and module independence.
  - Adherence to IEEE and HomeOwner standards.
  - Prototype modules/components designed to be incorporable into a future commercial version.
- Portability:
  - [N/A]

## 3.8 Supporting information

- Supplementary detail in Digital Home Use Case Model [HO2010].
- This SRS reflects a limited prototype scope intended to inform business decisions; all sensors/controllers/home are simulated and model realistic physical properties.

# 4 Verification

## 4.1 Functions

[N/A]

## 4.2 Performance requirements

[N/A]

## 4.3 Usability requirements

[N/A]

## 4.5 Logical database requirements

[N/A]

## 4.6 Design constraints

[N/A]

## 4.7 Software system attributes

[N/A]

# 5 Appendices

## 5.1 Assumptions and dependencies

- An ISP providing broadband Internet access is available at the installation site.
- The DH gateway can communicate wirelessly with all home devices within 1000 feet indoors.
- The prototype operates in a simulated environment; no physical devices or homes are used.
- Security relies on industry-standard protocols such as TLS for web communications.
- DH depends on adherence to ASHRAE standards for HVAC-related behavior and compatibility.
- Daily backups and recovery mechanisms are available and correctly configured by a DH Technician.
- Organizational standards and processes (HomeOwner Inc. development process, coding and documentation standards) are available and applied.

## 5.2 Acronyms and abbreviations

- ASHRAE: American Society of Heating, Refrigerating and Air-Conditioning Engineers
- CIO: Chief Information Officer
- DH: Digital Home
- DSL: Digital Subscriber Line
- FAQ: Frequently Asked Questions
- HVAC: Heating, Ventilation and Air Conditioning
- ISP: Internet Service Provider
- PDA: Personal Digital Assistant
- RF: Radio Frequency
- SRS: Software Requirements Specification
- TLS: Transport Layer Security