Circuit Cellar (April 2006)

100 Pages·2006·14.43 MB·English

cover1.qxp 3/9/2006 1:43 PM Page 1
#189 April 2006
CIRCUIT
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THE MAGAZINE FOR COMPUTER APPLICATIONS
WIRELESS COMMUNICATIONS
GPS-Based Monitoring &
Tracking System for Vehicles
Easy Control with
Text Messaging
2.4-GHz Spectrum Analyzer
ZigBee-Based Sump
Pump Monitor
04>
7 25274 75349 9
$4.95 U.S. ($5.95 Canada)

TASK MANAGER
FOUNDER/EDITORIAL DIRECTOR CHIEF FINANCIAL OFFICER
Steve Ciarcia Jeannette Ciarcia
Guaranteeing Dependability
MANAGING EDITOR MEDIA CONSULTANT
Jennifer Huber Dan Rodrigues
R TECHNICAL EDITOR CUSTOMER SERVICE
eliability and accuracy are key elements to building a successful C.J.Abate Debbie Lavoie
wireless application.You want to be able to wirelessly monitor your proj- WEST COAST EDITOR CONTROLLER
ects with the confidence that the results are correct.The transmission Tom Cantrell Jeff Yanco
system used to send important data needs to be as dependable as it is CONTRIBUTING EDITORS ART DIRECTOR
Jeff Bachiochi KC Prescott
fast.The articles in this issue address these concerns and more, provid-
Ingo Cyliax
ing practical solutions you can use in your own projects. Fred Eady GRAPHIC DESIGNER
Mary Turek
If you’re planning to build a mobile application, a critical part will be George Martin
designing the system for tracking and monitoring.You’ll find some useful Ed Nisley STAFF ENGINEER
John Gorsky
tips in Jean Paul Talledo Vilela’s article about tracking the position of and NEWPRODUCTSEDITOR
John Gorsky
monitoring the functions of a mobile application (p.24).Jean Paul set up
microcontroller-based wireless sensor modules around a vehicle to PROJECT EDITORS
Steve Bedford
measure acceleration, strain, and temperature.The vehicle’s position is
Ken Davidson
tracked using a Garmin eTrex Legend GPS device.The data is then sent David Tweed
via a GSM cellular module to an Internet database server.Jean Paul
takes you through the development process step by step so you can
ADVERTISING
recreate this system for your own mobile application. 860.875.2199 • Fax:[phone] (cid:127) www.circuitcellar.com/advertise
We also have an article by Ken Merk, who built a monitor and control
PUBLISHER
system for use in a train yard (p.12).Sometimes locomotives sustain Sean Donnelly
damaging impacts when they connect toeach other.Ken’s system notifies Direct:860.872.3064, Cell:860.930.4326, E-mail:[email protected]
yard operators when an impact occurs so that they can stop the locomo- ADVERTISINGREPRESENTATIVE
Shannon Barraclough
tive from being connected to any others until it’s inspected.Preventing
Direct:860.872.3064, E-mail:[email protected]
further damage helps the train yard maintain a working fleet so there are
ADVERTISINGCOORDINATOR
fewer delays.Additionally, Ken’s goal was to help operators reduce the fre-
Valerie Luster
quency of hard impacts.In order to achieve these goals, he needed a way E-mail:[email protected]
to wirelessly send data and commands back and forth in a busy industrial
environment.Knowing he wouldn’t need a lot of storage capacity, Ken decid-
Cover photography by Chris Rakoczy—Rakoczy Photography
ed text messaging through a cell phone would work perfectly.An Analog www.rakoczyphoto.com
Devices ADXL210 accelerometer measures the force of impacts and a PRINTED IN THE UNITED STATES
BlueTree modem serves as the cellular link for sending text messages.
CONTACTS
When you’re building wireless systems, you have to deal with interference. SUBSCRIPTIONS
Unfortunately, a high-priced microwave spectrum analyzer is out of reach for Information:www.circuitcellar.com/subscribe, E-mail:[email protected]
Subscribe:800.269.6301, www.circuitcellar.com/subscribe, Circuit Cellar Subscriptions, P.O.Box 5650,
most of us.There is a solution though.In his article, Scott Armitage shares Hanover, NH 03755-5650
Address Changes/Problems:E-mail:[email protected]
his recipe for building a 2.4-GHz spectrum analyzer for about $50 (p.18).
GENERAL INFORMATION
He explains how to use a Chipcon CC2500 radio chip and an Atmel 860.875.2199, Fax:[phone], E-mail:[email protected]
EditorialOffice:Editor, Circuit Cellar, 4 Park St., Vernon, CT 06066, E-mail:[email protected]
ATmega48 microcontroller to create an effective system.Although this NewProducts:New Products, Circuit Cellar, 4 Park St., Vernon, CT 06066, E-mail:[email protected]
project doesn’t have all the bells and whistles that a $3,000 commercial- AUTHORIZED REPRINTSINFORMATION
860.875.2199, E-mail:[email protected]
grade analyzer has, it handles the basics of spectrum analysis extremely AUTHORS
Authors’e-mail addresses (when available) are included at the end of each article.
well.And that’s all you need for most of the applications you work on at
home.At a tiny fraction of the cost, Scott’s system is a solid investment.
CIRCUIT CELLAR®, THE MAGAZINE FOR COMPUTER APPLICATIONS (ISSN 1528-0608) is published monthly by Circuit Cellar
These are just a few of the great articles we have this month.Before I
Incorporated, 4 Park Street, Vernon, CT 06066.Periodical rates paid at Vernon, CT and additional offices.One-year (12 issues)
sign off, I also want to highlight Jeff Bachiochi’s column titled “Automating subscription rate USA and possessions $21.95,Canada/Mexico $31.95,all other countries $49.95.Two-year (24 issues) sub-
scription rate USA and possessions $39.95,Canada/Mexico $55,all other countries $85.All subscription orders payable in
Sudoku” (p.80).This column is for those of you who love (or obsess U.S.funds only via Visa, MasterCard, international postal money order, or check drawn on U.S.bank.Direct subscription orders
and subscription-related questions to Circuit Cellar Subscriptions,P.O.Box 5650,Hanover,NH 03755-5650 or call
about) Sudoku puzzles.Do you shred newsprint with a pencil and eraser 800.269.6301.
or printhalf a dozen copies of puzzles off the ’Net? If so, you’ll enjoy read- Postmaster:Send address changes to Circuit Cellar, Circulation Dept., P.O.Box 5650, Hanover, NH 03755-5650.
ing about the program Jeff wrote to cut back on the frustration of the
Circuit Cellar® makes no warranties and assumes no responsibility or liability of any kind for errors in these programs or schematics or for the
consequences of any such errors.Furthermore, because of possible variation in the quality and condition of materials and workmanship of read-
paper-and-pencil method and help him solve the really tough puzzles. er-assembled projects, Circuit Cellar® disclaims any responsibility for the safe and proper function of reader-assembled projects based upon or
from plans, descriptions, or information published by Circuit Cellar®.
The information provided by Circuit Cellar® is for educational purposes.Circuit Cellar® makes no claims or warrants that readers have a right to
build things based upon these ideas under patent or other relevant intellectual property law in their jurisdiction, or that readers have a right to
construct or operate any of the devices described herein under the relevant patent or other intellectual property law of the reader’s jurisdiction.
The reader assumes any risk of infringement liability for constructing or operating such devices.
[email protected] Entire contents copyright © 2006 by Circuit Cellar, Incorporated.All rights reserved.Circuit Cellar is a registered trademark of Circuit Cellar, Inc.
Reproduction of this publication in whole or in part without written consent from Circuit Cellar Inc.is prohibited.
4 Issue 189 April 2006 CIRCUIT CELLAR® www.circuitcellar.com

April 2006: Wireless Communications
FEATURES
12 Monitor and Control with Text Messaging
Ken Merk
Text Messaging Makes ATmega48-Based Spectrum
18 Low-Cost 2.4-GHz Spectrum Analyzer Remote Monitoring a Analyzer (p.18)
Scott Armitage Breeze (p.12)
24 Data Acquisition for Mobile Applications
Jean Paul Talledo Vilela
34 Solution to Stand-Alone ISP Programming
Low-Cost STK500-Based Project
Alton Harkcom
40 Optical Proximity Sensor for Robots (Part 2)
Open-Source PCB Layout Editor
Stuart Brorson
48 Wireless Sump Pump Monitoring System
David Kanceruk
Freescale Wireless Design Challenge Winner
ZigBee-Based Display for Monitor Your Sump Pump
58 Stock Clock Stock Market Data (p.58) with Ease (p.48)
Wireless Network Delivers Market Data
Richard Hoptroff
COLUMNS
62 APPLIED PCs
Get Started in Mechatronics
Fred Eady
68 ABOVE THE GOUND PLANE
RF Mixer Isolation and Coax Stub Filters
Ed Nisley
PPIICCDDEEMM--BBaasseedd PPrroojjeecctt ((pp..6622))
75 SILICON UPDATE
Rock ’Em and SoC ’Em
Tom Cantrell
80 FROM THE BENCH
Automating Sudoku
Jeff Bachiochi
AAcctteell’’ss FFuussiioonn FFPPGGAA DDeelliivveerrss tthhee
SSooCC GGooooddss ((pp..7755))
DEPARTMENTS
4 TASK MANAGER 94 INDEX OF ADVERTISERS
Guaranteeing Dependability May Preview
Jennifer Huber
96 PRIORITY INTERRUPT
8 NEW PRODUCT NEWS It’s an E-mail World
edited by John Gorsky Steve Ciarcia
93 CROSSWORD
6 Issue 189 April 2006 CIRCUIT CELLAR® www.circuitcellar.com

NEW PRODUCT NEWS Edited by John Gorsky
PROGRAMMABLE RADIO TRANSCEIVER MODULE GANGED RF BOARD-TO-BOARD CONNECTORS
The iDwaRF-168module combines a Cypress WirelessUSB- Samtec has added ganged RF board-to-board jacks,
LR CYWUSB6935 radio transceiver with an Atmel ATmega168 plugs, and cable assemblies (GRF1 Series) to its grow-
microcontroller. Separate transmit and receive antennas are inte- ing product line of MMCX, MCX, SMA, and MHF
grated into the PCB. An expansion connector provides a pro- connectors. Ganged RF cable plugs are offered for ter-
gramming interface for the microcontroller and eight I/O pins. minating two, four, six, or eight wires simultaneously
The CYWUSB6935 radio transceiver uses the worldwide unli- with a choice of a standard 26-AWG coax cable or a
censed 2.4-GHz ISMfrequency band. It uses a robust DSSS high-performance 26-AWG coax cable with a
transfer method with a data rate of 62.5 kbps and a 50-m range. 1.4 dielectric constant. The ganged assemblies are
The low standby power consumption of less than 1 µA is ideal- available with captive screw options for rugged appli-
ly suited for battery-powered wireless sensor networks. cations. Standard assemblies may be specified with
The royalty-free iDwaRF-Net firmware supports the process wire lengths from 6″to 1 m. Custom cable assemblies
of setting up wireless multipoint-to-point networks. The proto- are available with quick turnaround in prototype to
col aims at a reliable bidirectional communication between midsize quantities.
one hub and numerous sensors or actuators in multipoint net- Ganged RF board-to-board jacks and plugs are also
works. The full protocol (error detection and correction, auto- available for terminating two, four, six, or eight con-
matic channel selection, etc.), which is encapsulated in con- nectors simultaneously. Standard board spacing is
venient C functions, can be extended with user-defined func- 4.5 mm. Captive screw receptacles are available on
tions. The iDwaRF-168 module can be set up as a hub, as well the jacks for mating with wire assemblies.
as a sensor or actuator module. Prices vary by pin count and cable length. The aver-
The iDwaRT-168 costs $35. The age price per position is
iDwaRF-StarterKit-S starter kit, $15for a cable system
which includes three 168 modules, and $8for board-to-
two SensorBoxes, and a HubAdapter, board sets (per posi-
costs $148. tion).
chip45.com Samtec,Inc.
www.chip45.com www.samtec.com
8 Issue 189 April 2006 CIRCUIT CELLAR® www.circuitcellar.com