Myalarm V-LED1 Manuale Utente Scaricare il pdf

Issue 194 September 2006

CIRCUIT CELLAR

www.circuitcellar.com

will give you a status report when you

call home and enter your security code

SYSTEM OVERVIEW

The system’s base unit receives sta-

tus data from the remote wireless sen-

sors and acts on it appropriately. It

lights an LED to alert you when an

error condition exists. You can press a

button for an audio report from the

remote sensors. If you’re away from

home, you can call the phone number

connected to the base unit, enter a

security code, and receive the report.

A garage door module is attached to

the inside of a garage door. It trans-

mits the door’s position to the base

unit. An error message is sent if the

door is open.

A water level detection module peri-

odically transmits water level data to

the base station. It sends an error mes-

sage if the level is above a calibrated

trip point. It uses a flexible clear vinyl

tub

e to detect the water level. You can

place the tube in a sump pump hole,

bathtub, or hot tub in order to prevent

overflows that can cause water damage.

A temperature module periodically

takes the current temperature and

compares it to upper and lower limits

that you set. If the temperature is

beyond either limit, the module trans-

mits an error message to the base sta-

tion; otherwise, it transmits a non-

error message. The reading is also

transmitted to the base station. This

module allows you to monitor heating

and air conditioning systems. You can

Irec

ently designed a multifunctional

wireless alarm system that’s based on

the IEEE 802.15.4 wireless data modem

specification. Implemented with

Freescale Semiconductor’s SimpleMAC

software, the system runs on micro-

controllers in the MC9S08GT family.

A popular cartoon character who

decided to become an inventor was

the inspiration for my design, which I

call the Everything is OK Alarm. One

of his inventions looked like a smoke

alarm that beeped loudly and con-

stantly. Over the loud beeping, he

yells, “This is an Everything is OK

Alarm. It keeps beeping as long as

everything is OK.”

Actually, my alarm is more like a

security alarm system, yet very differ-

ent. How many times have you won-

dered if you closed the garage door

after leaving your house? Have you

ever worried about your heat shutting

off and your water pipes freezing? Or,

maybe you’ve worried during a storm

that your sump pump has quit and

your basement is filling with water.

A traditional security system acti-

vates only when something bad hap-

pens (e.g., a burglar opens a window).

It will not notify you when your front

door isn’t locked. Nor can it monitor

such things as water in your basement

and a particular room’s temperature.

My syste

m can do all of these things

and more. You can keep tabs on every-

thing from the position of your garage

doors to the water level in your hot tub.

The system’s remote wireless sensors

also use it to monitor the temperature

near water pipes.

INSTALLATION & OPERATION

The base unit is installed by con-

necting a phone line to an RJ11 wall

jack. You can plug a telephone into

the ja

ck. Power can be supplied to the

base unit with the wall plug power

supply or a USB cable plugged into a

PC’s USB port. (I used the power sup-

ply that came with the Freescale

Wireless Design Challenge contest kit.)

A speaker is plugged into the speaker

jack. A set of unamplified computer

speakers is sufficient for this purpose

Now let’s focus on the processes of

powering up and programming the

system. Programming is necessary at

power-up. The base unit uses a built-

in speech synthesizer to guide you

through the programming process. It

asks for a network number and securi-

ty code for dial-up access to be pro-

grammed with the push buttons on a

Freescale MC13192-EVB. The purpose

of the network number is to allow

more than one system to work with-

out each reacting to the sensor mes-

sages from the others. The base unit

won’t act on messages unless the data

packet is properly formatted and the

network number matches. The net-

work number must be the same for

the base unit and all of the remote

sensors that the base unit monitors.

At this point, the unit will announce

that the system is ready to use.

The unit lights LED4 on the

FEATURE ARTICLE by Carl Smith

Multifunctional Wireless

Alarm

Carl’s multifunctional wireless alarm system can monitor everything from the doors to the

sump pump in your house.The system features an MC13192 SARD board and several wire-

less sensors. When the alarm is activated, simply place a call to your house to obtain a sta-

tus report.

2609016 Smith.qxp 8/4/2006 2:18 PM Page 30

1 2 3 4 5 6 7 8

Sommario

Pagina 1 - Multifunctional Wireless

30Issue 194 September 2006CIRCUIT CELLAR®www.circuitcellar.comwill give you a status report when youcall home and enter your security code.SYSTEM OVE

Pagina 2 - HARDWARE DESIGN

www.circuitcellar.comCIRCUIT CELLAR®Issue 194 September 2006 31MC13192-EVB when a remote sensorreports an error condition. You canpress S1 for a s

Pagina 3 - Figure 1

32Issue 194 September 2006CIRCUIT CELLAR®www.circuitcellar.comwas a good decision by the designers.In most applications, the module sim-ply would be

Pagina 4 - GARAGE DOOR SENSOR

hardware integration on theMC13192-SARD, the design of thissensor was software only, but this pro-vided an easy starting point to startsoftware develo

Pagina 5 - TEMPERATURE SENSOR

34Issue 194 September 2006CIRCUIT CELLAR®www.circuitcellar.comThe minor exception I mentionedearlier is power management. One ofthe great things abou

Pagina 6 - Made Of?

What Are Yo uMade Of?Show us what you’re made of by entering the MSP430 eZ Design Contest. Pit yourselfagainst other top designers from around the wor

Pagina 7 - Register Today & Save!

via a connection to the TP104 on thesolder side of the MC13192-SARDPCB. Ground is obtained from theJ101 BDM port pin 2. The signal isconnected to the

Pagina 8 - PEACE OF MIND

www.circuitcellar.comCIRCUIT CELLAR®Issue 194 September 2006 37Carl Smith ([email protected])has more than 12 years of experiencein electronic