Tom Petruzzellis (Vestal, NY) is an electronics engineer with 30 years’ experience, currently working with the geophysical field equipment department at the State University of New York – Binghamton. He is also an instructor there. Tom has written extensively for industry publications, including Electronics Now, Modern Electronics, QST, Microcomputer Journal, and Nuts & Volts. He is the author of five earlier books: Electronic Sensors for the Evil Genius, Electronic Games for the Evil Genius, Build Your Own Electronics Workshop; STAMP 2 Communications and Control Projects; Optoelectronics, Fiber Optics, and Laser Cookbook, and Alarm, Sensor, and Security Cookbook, all from McGraw-Hill.