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Adaptive Thermostat With Bluetooth Technology

Trey LawrenceJennifer Ogunlowo

Scott SnyderMark Youngblood

ECE4007L02, Group 7Georgia Institute of Technology

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Outline

• Overview with example

• Benefits

• Design details

• Specifications

• Bringing it to market

• Marketing

• Demonstration

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Project Overview

• Automated household thermostat equipped with Bluetooth senses presence of users’ Bluetooth-enabled cell phones

• Temperature adjusted according to which users are present

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Example

1. User enters home equipped with Bluetooth thermostat

2. Bluetooth adapter detects presence of user

3. Microcontroller responds by applying user’s saved temperature setting

4. Adapter detects user leaving home

5. Microcontroller applies idle temperature

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Benefits

• Increases level of automation– Saves time– Reduces human error

• Saves energy

• Costs less than current high-end thermostats

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System Design

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System Design

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Design Details

• Detect cell phones at up to 100m

• Handle up to four users at once with weighted averages

• Utilize basic temperature control algorithm

• Comply with Energy Star standards

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Specifications

• Bluetooth Class 1 radio modem– Detection range of 100m– SPI-compatible– Low power

• MSP430 microcontroller– Two built in SPIs– Adequate program/data storage– Low power

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Specifications

• Digital temperature sensor– SPI-compatible– .5°C accuracy

• Development board– 84x48 pixel LCD display– JTAG connector for easy programming– Joystick with four directions, select– 3.3V voltage regulator

• HVAC control– 3 SPST relays– Connects Heating, A/C, and Fan lines with 24VAC

when they’re turned on

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Bringing it to Market

• Print circuit onto Printed Circuit Board (PCB)

• Design enclosure with similar LCD and larger joystick

• Utilize more advanced temperature control algorithms

• Ensure compatibility with most HVAC systems

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Marketing and CostDevelopment Costs Production Costs

Total Cost for N units

4 Engineer’s Salary (57 Hours) $6532.30

Overhead (Electricity, Building) $500,000.00

Parts N * $153.96

Assembly & Testing N * $20.00

Total $506,532.30 Total N * 173.96

$506,532.30 + (N * $173.96)

Current thermostat options include Mechanical, Digital, & Wireless. No product was found that contains the features and specifications proposed in this project

The market for Heating, Ventilation, and Air Conditioning (HVAC) units has grown 24% over the last 19 years.

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Schedule

11/05/07 – Finish code segments, integrate– Bluetooth control– Temperature management– Menu system using LCD + joystick

11/29/07 – Add HVAC functionality

12/05/07 – Final demonstration

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DemonstrationCorrect operation of the thermostat will be tested with the following procedure:

1. An observer will choose an arbitrary temperature to be programmed into a blue-tooth compatible device.

2. The device will link with the thermostat and the correct signals will be sent to a simulated HVAC based on the room temperature.

3. A Hot or Cold source will be applied to the temperature sensor on the thermostat until the desired temperature is reached, and it is expected that the thermostat will then shut off.

This procedure will be repeated a second time with two simultaneous users in the room to verify correct multi-user operation.

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Questions?

At the beginning of 2007 there were more than 1 billion Bluetooth devices in circulation.