Gestión administrativa: Técnica contables

Details This book discusses the basic components of any alarm system. All alarm systems have two basic functions. First, they monitor their environment looking for a change such as a door or window opening or someone moving about in the room. Second, they alert the legal owner or user to this change. The system described in this book uses a scanning type software to detect intruders. It behaves like a guard dog, pacing up and down the fence line on the lookout for either an intruder or a familiar person. If you have an alarm key, you can disarm the system and enter. With the scanning method, the software is easy to write and explain. It can scan eight alarm zones plus two special fire zones in about one second. You don’t have to be an electrical engineer to install an alarm system, just a decent carpenter, painter, and plasterer! Because this alarm system runs on 12 volts, you don’t have to be a licensed electrician either to install it. The alarm system presented here uses Python software on the Raspberry Pi combined with some elementary electronic circuits. The code described in the book, as well as CAD files and a bill of materials for the alarm panel, are available for free downloading. The book provides the reader with examples of typical configurations coming straight from the author‘s experience. After reviewing the hardware components typically used in common alarm systems, the author shows how to plan one yourself. To implement a modular alarm, no matter if it is for a single house or for a business or restaurant, the book shows how to skillfully combine a Raspberry Pi with small auxiliary electronic circuits. These are not installation instructions but food for thought that will enable readers to find a solution to their needs. Search... -1 Building a High-Tech Alarm System with Raspberry Pi 1 All rights reserved. 4 Contents 5 1 • Introduction to Alarm Systems 7 Alarm System Sensors - Door / Window Contact 7 Motion Detectors 8 Glass Break Sensor 9 Fire Alarm Sensors - Heat Detectors 9 Fire Alarm Sensors - Smoke Alarms 11 Access Control 14 Block diagram of the alarm system 16 References 16 2 • Hardware 17 3 • Human Interface 22 LCD Display 22 Voice Output 29 Human Interface - RFID Card Reader 30 4 • Software 33 Version 5.1 33 Version 5.2 40 5 • Printed Circuit Board 47 Assembly 47 Printed Circuit Board 51 6 • Alarm System Wiring 57 Zone Test Switches 57 Constructing the Harnesses 59 Testing the Harnesses 62 Wiring the Sensors 63 7 • Planning your Alarm System 70 Step 1 – The Walk-about 71 Typical Four-Bedroom House 71 Typical Pub or Restaurant 76 Commercial Office Space 79 Laboratory 81 8 • Future Enhancements 83 Running Alarm Program from Boot 83 Running Raspberry Pi from 12 volts 84 Water / Moisture Detector 87 Adding a Door Solenoid 88 Links 92 Appendix 93 Bill of Materials 93 Software 94 Schematics 112