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One of the best kept secrets of the security and access control industry is just how simple the monitoring hardware actually is. It is the software that runs on the monitoring hardware that makes it seem cool.

The original BeagleBone or the new BeagleBone Black, have all the computing power you need to build yourself an extremely sophisticated access control, alarm panel, home automation, and network intrusion detection system.

All for less than a year's worth of monitoring charges from your local alarm company!

Don't get me wrong, monitored alarm systems have their place. Your elderly mother, for example, or your convenience store in a bad part of town. There is no substitute for a live human on the other end of the line.

That said, if you are reading this, you are probably a builder or a hobbyist with all the skills required to do it yourself.

BeagleBone is used as the development platform. The modular design of the alarm system allows the hardware to be used with any of the popular single board computers available in the market today. Any single board computer with at least eight accessible input/output pins will work. For example, the Arduino series of boards, the Gumstix line of hardware, and many others.

The block diagram of the alarm system is shown in the following diagram:

Block Diagram

The adapter board is what is used to connect the single board computer to the alarm system. The adapter board comes with connectors for adding two more zones and four more outputs. Instructions are provided for adding zone inputs and panel outputs to the software.

An alarm zone can be thought of as having two properties. The first is the actual hardware sensors connected to the panel. The second is the physical area being protected by the sensors.

There are three or four types of sensors found in home and small business alarm systems. The first and most common is the magnetic door or window contact. The magnet is attached to the moving part (the window or the door) and the contacts are attached to the frame of the door or window. When the door or window is opened past a certain point the magnet can no longer hold the contacts closed, and they open to signal an alarm.

The second most common sensor is the active sensor. The PIR or passive infrared motion sensor is installed in the corner of a room in order to detect the motion of a body which is warmer than the ambient temperature.

Two other common sensors are temperature rise and CO detectors. These can both be thought of as life saving detectors. They are normally on a separate zone so that they are not disabled when the alarm system is not armed. The temperature rise detector senses a sudden rise in the ambient temperature and is intended to replace the old ionization type smoke detectors. No more burnt toast false alarms! The CO detector is used to detect the presence of Carbon Monoxide, which is a byproduct of combustion. Basically, faulty oil or gas furnaces and wood or coal burning stoves are the main culprit.

Temperature Rise or CO Detector

Physical zones are the actual physical location that the sensors are protecting. For example "ground floor windows" could be a zone. Other typical zones defended by a PIR could be garage or rear patio. In the latter case, outdoor PIR motion sensors are available at about twice the price of an indoor model. Depending on your climate, you may be able to install an indoor sensor outside, provided that it is sheltered from rain.

The basic alarm system comes with four zone inputs and four alarm outputs. The outputs are just optically isolated phototransistors. So you can use them for anything you like. The first output is reserved in software for the siren, but you can do whatever you like with the other outputs. All four outputs are accessible from the alarm system web page, so you can remotely turn on or off any number of things.

For example, you can use the left over three outputs to turn on and off lawn sprinklers, outdoor lighting or fountains and pool pumps.

That's right. The alarm system has its own built in web server which provides you with access to the alarm system from anywhere with an internet connection. You could be on the other side of the world and if anything goes wrong, the alarm system will send you an e-mail telling you that something is wrong. Also, if you leave for the airport and forget to turn on or off the lights or lawn sprinkler, simply connect to the alarm system and correct the problem.

You can also connect to the system via SSH or secure shell. This allows you to remotely run terminal applications on your BeagleBone.

The alarm system, actually has very little to do so long as no alarms occur. The alarm system hardware generates an interrupt which is detected by the BeagleBone, so the BeagleBone spends most of its time idle.

This is a waste of computing resources, so the system can also run network intrusion detection software. Not only can this alarm system protect you physical property, it can also keep your network safe as well. Can any local alarm system company claim that?

Iptraf

Iptraf is short for IP Traffic Monitor. This is a terminal-based program which monitors traffic on any of the interfaces connected to your network or the BeagleBone.

My TraceRoute (mtr-0.85)

Anyone who has ever used trace route on either Linux or Windows will know that it is used to find the path to a given IP address. MTR is a combination of trace route and ping in one single tool.

Wavemon

Wavemon is a simple ASCII text-based program that you can use to monitor your WiFi connections to the BeagleBone. Unlike the first two programs, Wavemon requires an Angstrom compatible WiFi adapter. In this case I used an AWUS036H wireless adapter.

hcitool

Bluetooth monitoring can be done in much the same way as WiFi monitoring; with hcitool. For example: hcitool scan will scan any visible Bluetooth devices in range. As with Wavemon, an external Bluetooth adapter is required.

Your personal security system

These are just some of the features of the security system you can build and customize for yourself.

With advanced programming skills, you can create a security system with fingerprint ID access, that not only monitors and controls its physical surroundings but also the network that it is connected to.

It can also provide asset tracking via RFID, barcode, or both; all for much less than the price of a commercial system.

Not only that but you designed built and installed it.

So tech support is free and should be very knowledgeable!

Summary

A block diagram of the alarm system is explained. The adapter board is what is used to connect the single board computer to the alarm system. The adapter board comes with connectors for adding two more zones and four more outputs. Instructions are provided for adding zone inputs and panel outputs to the software.

Resources for Article:

Further resources on this subject:

• Building a News Aggregating Site in Joomla! [Article]
• Breaching Wireless Security [Article]
• Building HTML5 Pages from Scratch [Article]