Reliability and accuracy are key elements to building a successful wireless application. You want to be able to wirelessly monitor your projects with the confidence that the results are correct. The transmission system used to send important data needs to be as dependable as it is fast. The articles in this issue address these concerns and more, providing practical solutions you can use in your own projects.

If you’re planning to build a mobile application, a critical part will be designing the system for tracking and monitoring. You’ll find some useful tips in Jean Paul Talledo Vilela’s article about tracking the position of and monitoring the functions of a mobile application (p. 24). Jean Paul set up microcontroller-based wireless sensor modules around a vehicle to measure acceleration, strain, and temperature. The vehicle’s position is tracked using a Garmin eTrex Legend GPS device. The data is then sent via a GSM cellular module to an Internet database server. Jean Paul takes you through the development process step by step so you can recreate this system for your own mobile application.

We also have an article by Ken Merk, who built a monitor and control system for use in a train yard (p. 12). Sometimes locomotives sustain damaging impacts when they connect to each other. Ken’s system notifies yard operators when an impact occurs so that they can stop the locomotive from being connected to any others until it’s inspected. Preventing further damage helps the train yard maintain a working fleet so there are fewer delays. Additionally, Ken’s goal was to help operators reduce the frequency of hard impacts. In order to achieve these goals, he needed a way 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 decided text messaging through a cell phone would work perfectly. An Analog Devices ADXL210 accelerometer measures the force of impacts and a BlueTree modem serves as the cellular link for sending text messages.

When you’re building wireless systems, you have to deal with interference. Unfortunately, a high-priced microwave spectrum analyzer is out of reach for most of us. There is a solution though. In his article, Scott Armitage shares his recipe for building a 2.4-GHz spectrum analyzer for about $50 (p. 18). He explains how to use a Chipcon CC2500 radio chip and an Atmel ATmega48 microcontroller to create an effective system. Although this project doesn’t have all the bells and whistles that a $3,000 commercial-grade analyzer has, it handles the basics of spectrum analysis extremely 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.

These are just a few of the great articles we have this month. Before I sign off, I also want to highlight Jeff Bachiochi’s column titled “Automating Sudoku” (p. 80). This column is for those of you who love (or obsess about) Sudoku puzzles. Do you shred newsprint with a pencil and eraser or print half a dozen copies of puzzles off the ’Net? If so, you’ll enjoy reading about the program Jeff wrote to cut back on the frustration of the paper-and-pencil method and help him solve the really tough puzzles.

jennifer.huber@circuitcellar.com