• Background and Introduction• System Operation Video• Watchbird™ Web Interface and Database• Watchbird™ Server• Watchbird™ Base Station• Sensor End Circuitry and Door Lock• Conclusion• Questions• Demo

Goals User-Installable User-Expandable No Monthly Fee Peace-of-mind away from home

Motivation All similar products expensive and do not offer all of Watchbird™’s features Who hasn’t wondered “Did I lock my door?” or “Is my oven off?”

SMS text message to query sensor status Text message reply with sensor status

SMS text message to lock or unlock door Door is locked or unlocked Text message reply with new status of all sensors

Inputs

Outputs

Watchbird

Setup InformationCell Phone Requests

Sensor Data

“ Status” Texts to UsersDoor

Locking/Unlocking

Security System Monthly Fee Does not generally lock/unlock door Difficult/expensive to query remotely if available Does not give status of appliances

Internet Door Lock Monthly Fee Can only query over the internet (user needs a smartphone if away from a computer) Will not give status of oven, windows, etc.

Server

Server Program

DatabaseConfigurati

on Web Interface

Base Station and Cell Phone Messaging Processing

SQL Server

Program reads settings from database Internet Information

Service (IIS)

Website read from

and write to database

User Access Menu Log in Change Password

Watchbird Configuration Menu User Profile Sensor List Format Validation

Dynamic Website Visual Web Developer

Microsoft ASP.NET C# Microsoft SQL Database

ApplicationApplication QueryQuery DatabaseDatabase

Connection to serverConnection to server

SQL ServerSQL Server SQL Update CommandSQL Update Command

Web Interface

d Watchbird

Password

Request (Actuator)

d Watchbird

1234abcd lock door

d Watchbird

1234abcd unlock door

d Watchbird

1234abcd query

Resulting Email:Resulting Email:

1234abcd lock door1234abcd lock door

6041234567 / 6041234567 / ChickadeeTechChickadeeTech

Message Format:Message Format:

Queries andLock/Unlock Requests

Sensor StatusUpdates

Check for Connecting Base Stations Listen on server socket Store connection and wait for machine ID Add base station to connection map

Check for Queries Check and parse emails Get information from database Store Waiting Message Request (WMR)

Process WMRs Check and process replies from base stations Generate and send response message to user Check for timeout conditions

PICDEM.net 2 PICDEM.net 2 development development board board

EthernetEthernet Analog and Digital I/O Analog and Digital I/O PinsPins

Linx LR RF receiver Linx LR RF receiver and transmitter and transmitter

Mounted to PCBMounted to PCB Connected to Connected to Microcontroller’s Microcontroller’s Digital I/ODigital I/O

RX

M-4

18-L

R

TX

M-4

18-L

R

ANT

ANT

To MicrocontrollerTo Microcontroller10 μF

PCB

10 Ω

3.3 V

Base Station Powered On

Connect to Server

Send Machine ID

Number

Wait for Request

Receive Request From

Server

Parse Message

Send Lock or Unlock

Request

Query Each Sensor

Form Response Message

Send Reply to Server

Digital I/O pins used to transmit and receive data Digital I/O pins used to power down receiver and transmitter when not in use Data is encoded and decoded by the base station software

Receive Request

Power-up Transmitt

er

Send Data

Power-Down Transmitter, Power-

Up Receiver

Receive Data

Power-Down

Receiver

SSent by base station: 10 address bits 8 data bits Unique data bit codes for query, lock, and unlock

Received by sensor-end: 10 address lines Data relayed if address matches 8 data output lines

Sent by sensor end:Sent by sensor end: 10 address lines10 address lines 8 data lines8 data lines

Received by base station:Received by base station: 10 address bits10 address bits 8 data bits8 data bits

addresaddresss

receiver,receiver,decoderdecoder

encoder,encoder,transmitttransmitt

erer

addresaddresss

addresaddresss

timing timing delaydelay

sensor sensor inputinput

sensosensorr

Timing delayTiming delay Finish receiving beforeFinish receiving before beginning to transmit beginning to transmit 555 timer on each data line555 timer on each data line

received received datadata

transmitted datatransmitted data

Sensor inputSensor input XNOR gate on each data lineXNOR gate on each data line Sensor output connected toSensor output connected to each data line each data line Redundancy provides errorRedundancy provides error checking checking

data sentdata sent 11 00 11 00 11 00 11 00sensor sensor closedclosed 11 00 11 00 11 00 11 00sensor sensor openopen 00 11 00 11 00 11 00 11

VVCCCC

VVCCCC

normalnormally ly

closedclosed

normalnormally ly

openopen

SS

RR

QQ

S R Q

1 1 hold

0 1 0

1 0 1

Bi-state switch:Bi-state switch: single-pole double-throw single-pole double-throw Switch de-bouncingSwitch de-bouncing

Prevent intermediate Prevent intermediate statesstates 2 NAND gates2 NAND gates Flip-flopFlip-flop

timing timing delaydelay

sensor sensor inputinput

addresaddresss

addresaddresss

receiver,receiver,decoderdecoder

encoder,encoder,transmitttransmitt

erer

comparatcomparatorsors

timing timing extensionextension

locking locking systemsystem

sensosensorr

ComparatorsComparators Check for unlock or lockCheck for unlock or lock Output normally highOutput normally high Output goes low if data matchesOutput goes low if data matches

Timing extensionTiming extension 555 timer555 timer Longer time constantLonger time constant

trigger (comparator trigger (comparator output)output)

555 timer output 555 timer output pulsepulse

Locking circuitryLocking circuitry Voltage shifter from 3.5 V to 6 VVoltage shifter from 3.5 V to 6 V H-bridge: permits locking and unlockingH-bridge: permits locking and unlocking Modified H-bridge: use original locking Modified H-bridge: use original locking mechanismmechanism

motormotor

VVCCCC

motormotor

keypad keypad circuitcircuit

H-bridgeH-bridge modified H-modified H-bridgebridge

Item Estimate Cost

Actual Cost

Amount Overbudget

Microcontroller $200 $213.68 $13.68 Microcontroller Extras $100 $238.27 $138.27 Display and Keypad $64 $0.00 -$64.00 RF Transmitters/Receivers

$11 $303.64 $292.64

RF/Keypad Door Lock $150 $110.88 -$39.12Sensor End Components

$0 $269.47 $269.47

Sensors $30 $12.60 -$17.40Integration Components

$100 $101.64 $1.64

Cases $0 $94.77 $94.77 Miscellaneous Costs $100 $21.16 -$78.84Demo Materials $0 $108.93 $108.93 Total Costs $755 $1,475.

04 $720.04

Higher-security data transfer (encryption, Higher-security data transfer (encryption, etc.) for etc.) for production level production level Elimination of TwitterElimination of Twitter

Text-to-email functionality added to Text-to-email functionality added to Chickadee Chickadee Tech server Tech server

Addition of more types of sensorsAddition of more types of sensors Hall effectHall effect TemperatureTemperature WaterWater Power usagePower usage

Internet queryInternet query Eliminates text message fee when user is Eliminates text message fee when user is near a near a computer computer

Base Station Microcontroller and Circuitry $15 Base Station RF Receiver and Transmitter $15 Base Station Case, power supply, etc. $20 Base Station Total $50

Sensor End Circuitry $6 Sensor End RF Receiver and Transmitter $20 Sensor End Case, batteries, etc. $10 Sensor End Total $36

Door Lock Microcontroller and Circuitry $15 Door Lock RF $15 Door Lock and Actuator $20 Door Lock Case, batteries, etc. $10Door Lock Total $60

Offer “Starter Kit”Offer “Starter Kit” Base Station and 2 sensorsBase Station and 2 sensors ~$500 CAD~$500 CAD

Individual sensors to add on Individual sensors to add on ~$150 CAD~$150 CAD

Door Lock to add onDoor Lock to add on ~$225 CAD~$225 CAD

What worked?What worked? Documentation and planningDocumentation and planning Importance of functional and design Importance of functional and design specificationsspecifications Importance of diverse talents and Importance of diverse talents and abilities in a abilities in a group group

What didn’t work?What didn’t work? BudgetingBudgeting Time estimatesTime estimates RF complexityRF complexity Contingency time and moneyContingency time and money

Watchbird™ prototype successfully createdWatchbird™ prototype successfully created Fills need in marketFills need in market

Estimated production level cost realistic for Estimated production level cost realistic for most most users users Demonstrated interest from potential usersDemonstrated interest from potential users Unique, versatile, and useful product Unique, versatile, and useful product

Fred Heep for guidance and advice Fred Heep for guidance and advice throughout the throughout the term term Gary Houghton and Marius Haiducu for Gary Houghton and Marius Haiducu for machine shop machine shop support support Richelle Grist for artistic inputRichelle Grist for artistic input Dr. Sarah Walshaw for testing and Dr. Sarah Walshaw for testing and testimonialtestimonial

Microsoft Visual Web Developer and SQL Server Microsoft Visual Web Developer and SQL Server

express logos - express logos - http://www.microsoft.com/Expresshttp://www.microsoft.com/Express Schlage LiNK door lock - Schlage LiNK door lock - http://www.amazon.com/http://www.amazon.com/ Schlage-Wireless-Keypad-Starter-System/dp/ Schlage-Wireless-Keypad-Starter-System/dp/ B001NEK6K6 B001NEK6K6

Microsoft ASP.NET website (www.asp.net)Microsoft ASP.NET website (www.asp.net) Wikipedia (www.wikipedia.org)Wikipedia (www.wikipedia.org) Microsoft Developer Network Microsoft Developer Network (http://msdn.microsoft.com) (http://msdn.microsoft.com) Linx Technologies technical support line, and Linx Technologies technical support line, and Linx Linx Knowledgebase Knowledgebase (http://www.linxtechnologies.com/(http://www.linxtechnologies.com/ Support/Knowledgebase) Support/Knowledgebase) Digikey (www.digikey.com)Digikey (www.digikey.com) Microchip user guides and datasheetsMicrochip user guides and datasheets

Not currently available in CanadaNot currently available in Canada $299 USD (Amazon.com)$299 USD (Amazon.com) Need data-enabled phone to send Need data-enabled phone to send query/lockquery/lock

Can get text message updates on regular Can get text message updates on regular phone phone when someone enters the home when someone enters the home

$12.99/month USD $12.99/month USD

ApplicationApplicationQueryQuery

InformationInformation

DatabaseDatabase

Connection to serverConnection to server

SQL ServerSQL Server

SELECT * FROM UserProfile WHERE TextPassword = @TextPassword AND Cell1 = @Cell

SQL Select CommandSQL Select CommandWeb Interface and Server Program

Message Type ID

Data Size

Data

1 04 0123

ID Message Type

Message Contents

0 Startup Machine ID of Base Station

1 Query List of Sensor Numbers

2 Lock List of Sensor Numbers

3 Unlock List of Sensor Numbers

4 Status List of Sensor Statuses

Software samples every 10 μs to find encoded data start sequence, ends in middle of peak For decoding data, “peak following” system used assuming a transmission period of 400 μs

Improved stability for small timing errorStart in

middle of peak

Sample every 10 μs until voltage changes (max

200μs)

Wait 200 μs to find middle again

Each peak 400 μs long Each encoded bit consists of three levels, repeated once Address pins can float Encoded one: ‘010’ Encoded zero: ‘110’ Start sequence is encoded 1-0-1-0-1Encoded one: Encoded

zero:

Timing delay Finish receiving before beginning to transmit 555 timer on each data line

received received datadata

555 timer capacitor555 timer capacitor

555 timer output 555 timer output pulsepulse

RR

SS

QQ

QQ

++--

S R Q

1 1 hold

0 1 0

1 0 1

1 1 unstable

++--

VVCCCC

triggetriggerr

outpuoutputt

LLLL

LLHH

oonn

LL

HH

LLHH

LL

HHchargichargingng

LL

offoff

LL

HH

onon

LL

HH

dischardischargege

A.S. Sedra and K.C Smith, Microelectronic Circuits, 5th ed. New York, NY: Oxford University Press, Inc., 2004.

encoder - transmitter

(TXE-418-KH2)

address

pins(Vcc or

ground)

x8

x8antenn

a

GNDtransmit enable

data in

8-bitXNOR

Vcc

Vcc

address

address

pins(Vcc or

ground)

x10

sensor

receiver-decoder

(RXD-418-KH2)

data outantenna

Vcc

GNDaddress x1

0

delay circuit

data in

data out

Vcc

GND

x8

x1

595 – CD74HC7266E

encoder - transmitter

(TXE-418-KH2)

address

pins(Vcc or

ground)

x8

x8antenn

a

GNDtransmit enable

data in

8-bitXNOR

Vcc

Vcc

address

address

pins(Vcc or

ground)

x10

sensor

receiver-decoder

(RXD-418-KH2)

data outantenna

Vcc

GNDaddress x1

0

delay circuit

data in

data out

Vcc

GND

x8

x1

locking circuit

x8

595 – CD74HC7266E

x4 .Quad Timer

trigger

output

timing

GND

RC time constants

data fromreceiver-decoder

Vc

c

.Quad Timer

trigger

output

timing

GND

Vc

c

to XNOR

Vcc

… 8 RC pairs … x4

x4

x4

x4

x4

x8

… 8 … … 8 …

680Ώ100nF3.9M Ώ8.2k Ώ

x8

8k2

Ω

680

Ω

3M9

Ω4M7

Ω100

nF

.NTE 926

.NTE 926

8 bit compara

tor

A

equal

B

8 bit compara

tor

A equal

B

lockcode

(11000011)

unlockcode

(11001100)

x8

x8

.555 Timer

trigger

output

timing

GNDRC time

constants

data fromreceiver-decoder

Vc

c

.555 Timer

trigger

output

timing

GND

Vc

c

GND

Vc

c

Vc

c

GND

x8

to level shifter

Vcc

ctrl

ctrl

680

Ω

10

kΩ

10

kΩ

680

Ω

10

nF

10

nF

2M2

Ω

1 μF

595 – SN74HC688N

526 – NTE955M

.555 Timer

trigger

output

timing

GND

Vc

c

.555 Timer

trigger

output

timing

GND

Vc

c

.

Level Shifter

M

6 V

p

n

p

n

Vcc (circuit)

A in

B in

C in

D in

A out

B outC outD outGND

Vcc in Vcc out

6 V

p n p n

Vcc

(keypad)GND

(keypad)

G

S

D

S

D

G

G

D

S

D

S

G

D

S

D

S

G G

D

S

D

S

G G

526 – NTE955M

CD4504B

AOP609

Keypad/Microcontroller

Controlled Power

Actuator

RF Controlled

Power

Transistor Switch Circuit

Current flow when locking the door

Current flow when unlocking the

door

p n p n