Classic Computer Magazine Archive CREATIVE COMPUTING VOL. 9, NO. 8 / AUGUST 1983 / PAGE 100

The Hypertek HomeBrain. (evaluation) Glenn A. Hart.

The Hypertek Home Brain

People buy microcomputers for many reasons, ranging from teaching their children to be "computer literate' to game playing to word processing and accounting. One use which many potential and current owners assume is possible is "environmental control,' which can be defined as switching or modulation of devices which affect such aspects of the user's surroundings as temperature, humidity, and lighting. The benefits of using the intelligence of a computer for such control include the fact that you can allow different actions to occur based on preprogrammed circumstances, you can accommodate comples situations, you can provide for randomness to give the appearance of human presence, and you can realize significant energy cost savings without a negative effect on comfort or safety.

Widespread publicity has been given to "the home of the future' which includes such capabilities. Given the proliferation of "intelligent' appliances and other devices with imbedded microprocessors, today's microcomputerist can envision control systems, security protection, and other home systems which are vastly more sophisticated and flexible, while being less costly, than expensive dedicated systems.

Sound good? It should; the benefits described are real and possible, can make life much more enjoyable and save money. What is the catch? Simply that it doesn't make sense to use today's microcomputers for such functions.

There are many peripheral devices which allow control of external devices. Various switches, relays, analog-to-digital and digital-to-analog converters and other items are available. The big problems lie in interfacing these devices to the microcomputer and creating the software necessary to make them do anything useful.

While some of the mechanisms use standard serial or parallel ports, most do not. Even if they do, adding input/output ports, correctly wiring the cables and controlling the devices in software is far from trivial and depends heavily on the specific computer being used. If nonstandard I/O is required, the problems quickly escalate beyond the skills of even a reasonably experienced computerist.

Even if we assume that all the necessary peripheral devices have somehow been interfaced correctly to the computer, the software problem looms large. Custom devices require custom software. Even if this has been done, the biggest problem of all surfaces: very few current computers can do more than one thing at a time.

This means that the computer must be dedicated to the control function if anything useful is to be accomplished, rendering it totally unavailable for any other application. Few users will be willing to relinquish their cherished and costly computers or to buy another one just for home control. Even multi-tasking computers (ones that can execute more than one program at a time) don't fully solve the problem, since even they must be left running continuously.

These difficulties render most of the available control devices essentially useless except in special applications. While there are certainly many impressive applications of computers in device and environmental control, these are simply enyond the capabilities of most users.

The Hypertek Home Brain

A small company called Hypertek has developed a new product that solves these problems in a unique and clever manner. The Home Brain is a microcomputer dedicated to home control; it is tremendously flexible and powerful. The fascinating part is that you use your current microcomputer to program the microcomputer in the HomeBrain. All the capabilities of your main system, including disk drives, high level languages, and fancy video terminal, are used, but once the HomeBrain has been programmed you don't need to touch it at all unless you want to change the programming. Your main computer is totally uninvolved and free to use for whatever you want.

The heart of the HomeBrain is a 6502 microprocessor, the same one used in the Apple II, Atari, Commodore and other popular computers. Programs are stored in 2K of RAM, while 6K of ROM stores the HomeBrain control language discussed below. Thirty-two buffered digital inputs for a variety of devices are available, as are eight SPDT 3-amp, 125-volt relays for output devices. The number of unputs of relays can be doubled if desired.

A standard RS-232 serial port is used for communication with the main computer. Standard communication rates are 300 and 1200 baud. In a sense, the AC power cord is also on output, since the HomeBrain can also control 256 BSR or Leviton wireless home control modules by sending radio frequency signals through the AC wiring of the house. The HomeBrain includes provisions for inter-connecting other HomeBrains or Future intelligent peripherals from Hypertek over a simple two-wire twisted pair network. Since Hypertek also manufactures HomeBrain-like devices for commercial buildings and laboratory control, it is likely they will come out with new devices in the future, so the networking provision helps assure that the HomeBrain will remain state-of-the-art.

The HomeBrain is powered by a special uninterruptible power supply which uses a continuously charged battery system and can also handle brownouts down to 95 volts. Should normal AC power fail, the HomeBrain continues to operate normally for three hours controlling battery operated devices (but obviously not BSR modules, which are dependent on AC power). After this, the HomeBrain goes into a "sleep' mode which retains programming and other stored information for about a month.

The 32 inputs are desingned for switches, relays, or open collector or low voltage devices. This includes thermostats, motion detectors (ultrasonic, infrared, microwave or whatever), smoke alarms, moisture sensors, light detectors, and a multitude of other devices. While wires from most input devices are connected directly to the HomeBrain inputs, it is possible to use radio telemetry devices to send remote data to the HomeBrain without wires.

The relays of HomeBrain are normally used to turn on such devices as sirens and emergency lighting. Optionally available is analog input, which allows input of temperatures and other varying measurements rather than simple on/off status.

HomeBrain Language

Perhaps the biggest strength of the HomeBrain is the high level command language which is stored in ROM. To use it, a program is run on your main computer which communicates with the HomeBrain over the serial link. This program must be customized for the main computer to initialize the serial channel. Hypertek has versions for many different computers, ranging from the Commodore Vic 20 to a variety of CP/M systems. My own system uses somewhat idiosyncratic communications chips, but Hypertek was able to write a custom routine which worked perfectly almost immediately.

The HomeBrain language consists of commands which instruct the unit ot perform a wide variety of functions. Table I lists the available instructions grouped by function with an explanation of the purpose fo the commands. The language is based on the concept of a stack, which is a kind of buffer in which the command last entered is the first available. It can be viewed as analgous to a stack of dishes, in which you would put a new dish on top of the stack and also get the next dish from the top of the pile. Users of Hewlett-Packard calculators or computer languages like Forth will feel comfortable with HomeBrain immediately, but beginners may have some problems. Overall documentation is rather technical and could be improved for the novice.

Fortunately, the software that is operated on the main computer makes programming the HomeBrain quite a bit easier than it would be if all the instructions had to be entered one at a time. Using menus to guide the user, several of the most important functions are simplified to an interactive dialog so the user doesn't have to know the exact commands necessary to perform a function. The current software is reasonably good in this regard, but Hypertek is now up-grading it ot include simplified input of even more functions.

The major programming effort consists of defining networks of commands. The HomeBrain scans these networks four to ten times every second (depending on the complexity of the programming), and checks for inputs and other events. It then carries out whatever steps are necessary to implement your home control strategy.

Table 1 hints at the tremendous flexibility available. It is not exaggerating to say that practically anything is possible with the HomeBrain. The HomeBrain can do so many things that it clearly isn't possible to describe all of them in an evaluation like this, but perhaps a few examples will give you some idea of the possibilities.

The HomeBrain At Work

Security systems can use a wide variety of sensors. Doors and windows can be wired with magnetic switches (which can be imbedded in the frames so they are not visible to you or to a potential intruder). Microwave, infrared, or ultrasonic detectors can be used to sense motion, or audio discriminator devices can be used to sense the noise of an attempted break in. Some of these devices are available with radio frequency output with a receiver that is placed at the HomeBrain end and totally eliminates wiring.

Outputs can use several types of sirens or lights which can be made to turn on continuously or flash either inside or outside the house. If the appropriate equipment is connected to the HomeBrain, telephone contact can be made with the local police or fire department, ordinances permitting, or with commercial security services. Actuation of the system can be with simple switches with the normal exit and entry delays programmable for your needs, or a more clever system can be constructed. For example, the system could be disarmed by closing a door three times within 20 seconds.

The advantages of such a security system include total adaptability and the ability to structure multiple tiers of security. To avoid annoying and embarrassing false alarms, one could activate motion detectors inside the house only after a window or door switch was opened.

Handing a fire can be equally sophisticated. I use smoke detectors with RF outputs to avoid wiring. When actuated, these detectors emit a loud siren. My HomeBrain is programmed to allow me to deactivate my fire sequence within 30 seconds, in case the detectors have been set off by broiling lamb chops. If it is a real emergency, the HomeBrain activates sirens outside the house to alert neighbors, flashes outside lights and turns on battery operated emergency lighting which indicates the correct exit path from the house even in confusing, smoke filled circumstances. My house doesn't have forced air heating and air conditioning, but if it did the HomeBrain could have been programmed to turn off air motion if a fire developed. Since smoke circulation through a ventilation system is a major problem in home and commercial fires, this ability could be of great importance.

Controlling interior lighting can be much more powerful than with the BSR modules alone (by the way, normal BSR command consoles can still be used for manual control of BSR devices). Hitting a single switch once turns on the lights in an area. Hitting it again once or twice brings the lighting to pre-programmed dimming levels appropriate for different activities. The BSR modules can also be used for timed activites such as brewing coffee in the morning.

The timing abilities built into the HomeBrain can be used for other control purposes as well. Programming a set-back thermostat (when the temperature varies throughout the day) is easy. Depending on how your home heating system is set up, the HomeBrain can easily establish different heating programs for different areas of the house. Even in a one-zone system, a simulation of multi-zone operation can be programmed so that the thermostat in one area is in control during specified hours. Central air conditioning can be similarly controlled, or window units can be manipulated with BSR appliance modules.

The motion detectors used for security can also be used in conjunction with timers and other mechanisms for multiple purposes. In my house, the interior microwave sensors do nothing in the daytime unless security is activated. In the evening, a person entering the room turns on the lights. They stay on for ten minutes unless there is more motion in the room, in which case they continue on. Activating the security system programs the HomeBrain to consider motion an intrusion if certain other events have also taken place.

I also use microwave detectors on my doors to act as doorbells. A chime is rung whenever anyone approaches a door unless I have switched this function off to avoid constant ringing when my children are playing in the area. The "doorbell' also flashes lights in my third floor offic so I don't have to worry about hearing the chime if the door is closed (this also saved me the trouble of wiring anything to the third floor).

Other types of sensors expand the possibilities. Light sensors can automatically change the programming based on whether it is day or night. Moisture sensors can be used either to give an alarm if water enters a basement or to control automatic sprinkler systems. Unlike the simple timers that come with sprinkler systems, the HomeBrain can be programmed to turn on the water if the moisture drops below a certain level, unless it is between 11:00 a.m. and 3:00 p.m. when the sun is overhead and unless the program has been deactivated with a switch (we wouldn't want it to sprinkle our guests on Saturday afternoon). Controlling a greenhouse would be just as easy.

By now, you should be getting some idea of how truly powerful the HomeBrain is, and the tremendous control over your environment it can produce. My personal HomeBrain has converted my old house into an absolutely state-of-the-art "Home of the Future' with a minimum of fuss, and I can constantly change the operation of the system to reflect new circumstances, changing needs, or the appearance of new technology. My HomeBrain has been in constant use for six months with no problems whatever, and Hypertek has been very cooperative and helpful in advising me on installation and programming.


The cost of such a set up has to be considered in several contexts.

The $999 cost of the HomeBrain itself is only the beginning. Depending on the situation and how fancy you want to get, it is easy to spend twice this amount or more for the various motion sensors, smoke detectors, BSR modules and other devices which can be connected. If you already have a home computer, that cost is taken care of; otherwise, an inexpensive Vic, Atari, TI or the like will do just fine (and do many other useful things for you as well). Installation can be a bit of a chore and expense, although it is not at all difficult to do this yourself.

This is clearly quite a bit of money. However, a fully configured HomeBrain system still costs much less than most professional security systems and obviously is very much more flexible and powerful.

All in all, the HomeBrain is one of the most exciting devices I have come across in quite a while. We computer types can get a bit jaded with new technology, but the HomeBrain has never ceased to please me and amaze my friends.

Hypertek, 30-4 Farm Rd., Somerville, NJ 08876. (201) 874-4773.

Table: HomeBrain Language Commands.

Products: Hypertek HomeBrain (computer)