Classic Computer Magazine Archive CREATIVE COMPUTING VOL. 9, NO. 8 / AUGUST 1983 / PAGE 108

Home security with the Eye. (evaluation) Otto Moyen-van Slimming.

Home Security With the Eye

Moving into our own home after living in government housing for several years, one of our first concerns was a home security system. Since I had purchased a BSR remote controller and some lamp modules from Radio Shack, I needed a system that would interface with that system. After considering several commercial systems and thinking about designing my own, I decided to purchase the Eye, manufactured by Lehigh Valley Computer Corporation.

Since it is a new product, and I live in a remote location, I had only the company's brochures to go by. Their system has several features that prompted my decision. The Eye controller board plugs into one of the I/O slots of my Apple computer, providing a real-time clock capability apart from the security system. The Eye also provides the capability to control remotely up to 256 different strings of lights and appliances via the BSR modules. I decided to try it.

The package, which arrived by UPS in just a few days, contained the main controller card, four magnetic switches, a piezo-electric alarm, a 5 1/4 disk and a user manual.

The controller uses a standard 50-pin edge card with six-foot power cord and a back-up battery. The board contains an OKI5832 Clock Generator chip, five other ICs, and a six-post terminal connector to tie in the remote sensing devices. The alarm looked like a toy, so I tossed it aside. The magnetic switches, the kind that are readily available at electronic stores, consist of two parts--a magnet and the actual switch, closed when the magnet is near and open when the magnet is removed. This makes it a handy device to detect an open door or window.

I inserted the disk into the drive, hit the power-on switch and the Eye came up with a menu. I hit RESET and quickly made several back-up copies of the software (completely unlocker and mostly in Basic).

User Manual

The manual consists of a bound volume of 30 typeset pages. The manual briefly explains the systen and provides several examples of system implementations ranging from a basic system to a deluxe version with all the bells and whistles. It also covers the operation of the real-time clock and the remote BSR controller. The illustrations are hand drawn, but adequate; there are no photographs. I was satisfied with the quality of the documentation.

Following the installation instructions, I installed the controller card in slot #4, connected the piezo-electric alarm, plugged the connector into an AC outlet and booted the system.

System Operation

The Eye provides the capability to monitor three separate detection circuits via three channels: X, Y, and Z, so the house or building being protected can be divided into three zones. For example, channel X could monitor the doors, channel Y the windows and channel Z pressure sensitive mat switches, providing both peripheral and interior security (see Figure 1).

Each channel can monitor only switches of the same type, i. e., normally open (N/O) or normally closed (N/C). All N/C switches must be wired in series while all N/O switches must be wired in parallel, forming a loop for each channel. This ensures that a single switch will trigger the alarm function of the Eye. The system allows you to specify which channels are to be monitored and the type of switches in the loop of each channel.

The system operates in two modes--foreground and background. In the foreground mode, the Apple is totally dedicated to the Eye. The Applesoft Basic program, called Eye, runs continuously, monitoring the channels that are active, turning lights and appliances on and off, and even turning itself automatically on or off at specified times. The current time and system status is displayed on the screen.

The Eye provides an alarm or controls lights and appliances only when it is active. You can activate the system manually or the Eye will do so automatically. In the manual mode, the system becomes active five minutes after you command it to activate, thereby giving you five minutes to get out of the house or the building before the system is armed.

The Eye also can be programmed to activate or de-activate itself at a specific time (only two ON and two OFF time in a 24-hour period). You would use this mode if you wanted the system to be active during the same period each day. For example, the last employee of a store leaves at 9:00 p.m., so the Eye is programmed to become active at 21:05 (all times are based on a 24-hour clock) and to turn itself off at 7:55, just before the owner arrives to open the store.

Note that selecting the automatic mode from the menu when the Eye is programmed to be active will arm the system immediately, without the five-minute delay provided by the manual mode. Thus, if the system is programmed to activate at 6:00 p.m. and de-activate at 6:00 a.m., selecting the automatic mode at 10:00 p.m. will prevent you from leaving by an alarmed door without setting off the alarm.

The system allows you to specify the delay time between the detection of an intrusion and the time it actually gives the alarm. This time is variable, giving you any amount of time to enter while the Eye is active and de-activate the system before it turns on the siren and calls the police.

The system can be interrupted by a CTRL-C. This puts the Eye in the background mode, provided that the system was active when background was selected. In this mode the system does not read the real-time clock, so its timed functions do not operate, except for the entry delay. If any channel signals a change in state, indicating an alarm condition, however, the Eye will initiate an interrupt on the Interrupt ReQuest (IRQ) line to the Apple CPU. The programmed alarm functions (e.g., sounding the siren) are then executed.

If you are running a program while the Eye is active in background and don't want to be interrupted, you should set the Interrupt Disable flag in the Status (P) register. However, this effectively de-activates the Eye. Note also that to protect the background program, HIMEM must be set at 32624 before a foreground program is run.

Using the System

Figure 2 shows the menu options provided by the Eye program. First, since the clock had been set to Eastern Standard Time, I used option A to turn the clock back three hours to conform to Pacific Standard Time. The light next to my computer is controlled by a remote BSR module, so I tried the light timer next. After setting the house code using option B, I selected the light timer option. I set the timer to turn the light on in two minutes and turn it off one minute later. I then instructed the program to activate the timer. The Eye informed me that the timer had been activated and advised me to turn the screen off.

At the appointed time the Eye wrote the message CHANNEL 1 ON to the screen, beeped and turned on the light. "It works,' I thought. Then the message was repeated, followed by another beep. Another message and another beep. I turned the Apple off, popped the lid and checked the connections. Nothing seemed wrong, but I pulled the card and reseated it. I rebooted the system, reprogrammed the light timer: activate, message, beep, message, beep, message, beep. After 18 messages and 18 beeps, the message CHANNEL 1 OFF was displayed. Then a beep, and the lights went out, followed by 18 messages and 18 beeps.

The constant number gave me a clue to the problem. I listed the program and my suspicion was confirmed. The program checks the time and cycles through each of the 16 channels to see if the channel needs to be activated. The software checks only the hour and minute, however, so the first instance that the time is correct, it sends the turn-on code to the BSR module, prints the message and beeps. It then checks the other channels, and when it returns to the first channel, about three seconds later, the time still is correct, so it goes through the same process and continues until the minute number increments.

Thanks to the unlocked software, I was able to solve the problem easily with a bit of re-programming.

Turning to the alarm system, I hooked up one of the magnetic switches to channel X. Holding the switch in one hand and running through the menu, I activated the Eye.

I slowly moved the two sections of the switch apart and the alarm went off. The sound was definitely louder than the Apple beep, but I doubt that it would wake me from a sound sleep. Nor do I think it would scare a self-respecting burglar. I plan to add a siren.

I tried the system in both fore- and background modes, activating both manually and automatically. It all worked by the book. Having completed the bench test, I began to put the system to work by stringing a wire to the front door and mounting the switch. I ran into a problem, since the door is recessed in the frame and the magnet part has to be within 1/2 of the switch part. I found that a part of the frame had warped slightly, allowing just enough room to mount the switch without intering with the opening or closing of the door. If you should face the same problem, there are smaller switches available that will fit into tight places.

Once again I ran through the tests, but just as I became convinced that the system was working perfectly, the alarm went off although the door had not been opened. I checked all the connections, ran a few resistance checks--everything looked good. I rebooted the system and after a few minutes of perfect operation, another false alarm. This time I noticed that the lights had flickered slightly. I tried to cause a false alarm by wiggling the wires, pounding on the door, and turning lights and appliances on and off without success. Finally, as the refrigerator kicked in, another false alarm occurred.

I recalled information in the user manual on electrical noise triggering the Eye. There it was, the problem and the solution--an RC filter, using a 470 ohm resistor and a .01 mfd capacitor, should solve my problem, according to the manual. After a quick trip to Radio Shack, I tried the fix. After several minutes, another false alarm. The fix had not worked.

Checking and rechecking showed nothing wrong. I had started to tear out my hair when my wife entered with a box of electronic parts and suggested that something in there might be what I needed. Suppressing the urge to give her a crash course in electronics theory, I looked at various ICs, transistors, resistors, and other junk until I happened to see a 10 mfd electrolytic capacitor. Figuring that I had nothing to lose, I hooked it up and it worked!

Since putting in the fix, the system has worked exactly as the documentation says it should. With the system activated, if anyone triggers the alarm, the Eye immediately turns on all lights using BSR channel 15. This serves as a welcome light to members of the family coming home or as a warning to a burglar. If the system is not de-activated within the selected delay time (either by a RESET or simply by turning the computer off), the Eye turns on all other lights controlled by BSR modules, sounds the piezo-electric alarm and activates the phone dialer if one is connected. It will also send another signal using BSR channel 16 to turn on the optional siren.

The Eye survived several power failures. The back-up battery kept the real-time clock alive. After the power returned the disk in drive 1 rebooted the Eye which then picked up where it had left off. If the schedule called for the Eye to have activated itself during the time of the power outage, it did so immediately after the power returned.


Overall I am very satisfied with the Eye. The installation is not too difficult, and the manual seems to have covered all the bases. I would have appreciated a more detailed technical explanation of both hardware and software, but I expect that most people purchasing this system will not require such details.

There are a few troublesome aspects of the system, however. The RC filters should have been included on the board or space should have been allowed for them because other users also may have problems with spikes. The location of the capacitors that I installed to solve the problem could interfere with a card in slot 5.

The location of the terminal strip at the top, close to the Apple cover, may cause an accidental short (I used electrical tape to prevent this). The side facing the back of the Apple might have been a better location for the terminal strip. In addition, the terminal posts, especially the grounding terminal, are small, making it difficult to connect stranded wires. These are minor flaws in an otherwise good design.

A flaw in the software is the limit on the scheduler. The present system allows only one on-off cycle per BSR channel in a 24-hour period. Also, there are no provisions for programmed changes to the schedule, i.e., each day is identical to its predecessor. For example, you cannot specify that the TV comes on at 8:00 p.m. on Wednesday and at 7:00 p.m. on Thursday, or that you want the bathroom light to go on and off three times during the evening.

The ability to introduce an optional random factor, say +15 minutes, to the turn-on/off times would be a good feature to add, as would be the ability to control the start of a sequence based on input from an optical sensor measuring the amount of light outside. The Eye also fails to take advantage of the ability of the BSR system to dim or brighten individual lights.

Another limitation is having to install the controller in slot 4. This is necessary because all the PEEKS and POKES needed to access the card are hardcoded to slot 4 addresses, but it may conflict with other cards which require installation in that slot. The system would be more flexible if you could specify in which slot you had installed the controller.

I intend to make software changes to provide these additional capabillities and I would be interested in hearing from readers who have made custom changes.

In general, the real-time clock works well with programs running under DOS, but there are no provisions to use the clock in Pascal or CP/M. To protect the clock routine from being overwritten, HIMEM must be set almost 6K lower than its value after boot-up (32624 vs. 38400). If you run the Eye in background and run a fairly large Applesoft program with hi-resolution graphics, you may find that the Apple spends an inordinate amount of time "garbage collecting,' because of the small amount of memory left over for strings. If you use the clock function in your own programs, be aware that the manual has reversed the memory locations for hours: Location 32740 contains the "ones' and 32741 the "tens' of hours.

Commercial software packages, using modified operating systems, are generally not compatible with the Eye, as they tend to destroy any program in background. Since the IRQ interrupt line is usually not masked, however, you may see some unpredictable effects if the system is triggered. You might have to resign yourself to the fact that you cannot play Frogger and feel secure at the same time.


Aside from some limitations, the Eye is a quality product and an attractive alternative to other commercial security systems for Apple owners. Atari and Vic 20 versions of the Eye should be available soon from Lehigh Valley Computer. The system is relatively easy to install, and all options are menu-driven. Unless you accidentally set off the alarm at 2:00 a.m. and your neighbor comes over to punch you in the nose, it is very hard to get into trouble. When all else fails, a RESET cures all. The basic package sells for $250.

I plan to test some of the optional accessories that interface with the Eye, such as window breakage detectors, heat detectors, ultrasonic motion detectors, mat switches, and a phone dialer. I am going to have fun rewriting the existing code to provide additional features. This capability alone is worth the price of the package.

Lehigh Valley Computer Corp., 523 S. Clewell St., Bethlehem, PA 18015. (215) 868-1303.

Photo: Figure 1.

Photo: Figure 2. The Eye Menu.

Products: Lehigh Valley Computer Corp. Eye (computer apparatus)