RFID AC SWITCH

Final Presentation

April 24, 2008

Team Members

Ricardo CalderonElectrical EngineeringTeam LeaderResearch and DocumentationRFID ReaderPIC ProgrammingWebsite Design

Jonathan StanleyElectrical EngineeringResearch and DocumentationPower SupplyTRIAC ControlWebsite Design

Jerome WalkerComputer EngineeringResearch and DocumentationPIC ProgrammingWebsite Design

Corey TateElectrical EngineeringResearch and DocumentationPower SupplyTRIAC Control

Overview

• Introduction

• Problem

• Solution

• Technical/Practical Constraints

• Design Approach

• Hardware & Software Tests

• Completed Prototype

• Future Work

• Bill of Materials

• Questions

Introduction

• What is RFID?• How can RFID

technology be used?– Inventory Control– Personal Access

Problem

• There are no RFID AC Switches.• Many people are unfamiliar with the capability

RFID Technology.

Solution

• OEM RFID AC Switch• This will give manufacturers a quicker time to

market.

Implementations

• How can the RFID AC Switch be used?

– Light Control

– Security Access

– Outlet Control

Technical Constraints

Name DescriptionSwitching Voltage Must operate at 120 VAC.

Output Current Must have a maximum current of 15 amperes.

Read Distance Must have a read distance of at least 2”.

Authorized Tag Identification

Must read 125kHz tags.

Tag Quantity Must store at least 200 identification tags.

Practical Constraints

Type Name DescriptionManufacturability Size Must have dimensions of at most 4”

in length, 4” in width, and 2” in depth.

Health and Safety Safety Must meet UL (Underwriters Laboratories) guidelines.

Practical Constraints-Size

• RFID AC Switch must have dimensions of at most 4” in length, 4” in width, and 2” in depth

• Why?– Adaptability

Practical Constraints-Safety

• RFID AC Switch must meet UL (Underwriters Laboratories) guidelines

• How to meet these guidelines?– Proper Enclosure– Isolated Connections– Overcurrent Protection

Power Supply

ID-12 RFID READER PIC18F2620

TRIAC

Design Approach

5VDC 5VDC

Tag Information

0 or 5VDC

120 VAC

AC Device

0 or 120VAC

Hardware Tests

• Power Supply

• TRIAC

• RFID Reader

Power Supply Test

Power Supply Circuit Power Supply Circuit Output Voltage 5VDC

TRIAC Test

TRIAC Circuit

0VDC Sent to Gate TRIAC Output 0VAC 0VAC Output Wave

TRIAC Test

5VDC Sent to Gate

120VAC TRIAC Output

120VAC, 60Hz Output Wave

Voltage/Current Tests

Voltage/Current Test Results

 Expected

ValueMeasured

Value %Diff

Voltage (VDC) 5 5.042 0.84%

Operating Current (mA) Passive Mode 100 56.5 -43.5%

Operating Current (mA) Active Mode 200 67.1 -66.45%

Output VAC (VAC) 120 122.9 2.36%

RFID Reader Test

LED on when tag Present

ID-12 Reader RFID Tag

RFID Tag Code on Hyperterminal

RFID Reader Test Results

Test Pass/Fail

(Max Distance)2” Distance From Reader FAIL (1.50”)

Reader Inside of Wallet PASS (1.25”)

0.25” Thick Plastic Enclosure PASS (1.25”)

1” Thick Plastic Enclosure PASS (1.00”)

0.25” Metal Enclosure FAIL (NONE)

Other Tests

Constraint  Expected Value Actual Value %Diff

Tag Storage Quantity 200 250 25%

Dimmer Modes 3 3 0%

Software Tests

• Format (Erase)• Erase 1 Tag • Write (Store)• Read (Toggle)• Read (Timer 5s)• Read (Timer 10s)• Read (Dimmer)

Good Tag LEDErase Mode

Bad Tag LED

Mode SwitchesReset

Write Mode

Read Mode

Format/Erase Test

Write/Store Tag Test

Erase 1 Tag Test

Toggle - Sunny Day Test

Toggle - Rainy Day Test

Timer 5s & 10s Test

Dimmer Test

Completed Prototype

TRIAC Circuit

AC/DC Circuit

Serial Data Circuit

RFID & Microcontroller Circuit

Dimmer Stages

Future Work

• Meet read range constraint of 2”

• Design PCB to meet size constraint

• Design enclosure to meet safety constraint

• Improve dimmer functionality

Bill of Materials

Device Cost

RFID Reader $29.95

AC/DC Converter $8.50

TRIAC Circuit $2.99

Microcontroller $5.60

Dimmer Circuit $2.66

Serial Input Circuit $2.43

Total Cost: $52.13

Questions

Questions??