A Few Of My Electronics Projects

This has nothing to do with Electronics, but I promised the Wizard a place he could spin a story. Well here it is!   Just CLICK the Wizard

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The Digital Control System is responsible for most control applications related to any remote control functions in my house. This system limits certain locations from certain functions where that has been deemed necessary. Additional duties of the DCS unit are to provide for special lighting applications such as door bell activation turning on a porch light and timing its cycle as needed. The DCS Unit decodes the source of commands and provides routing data to other systems based on the source. For example, if a "Recall Stored Messages" command is received, the command and routing data will be sent to the VoiceTrax III unit. This will enable the speech unit to send the recalled messages to the source which requested it. The source data is also used to inhibit commands which originate from locations where it is desired they not be granted access.

The system is based on the 8085A processor, since it is advantagous to keep all systems hardware compatible with each other. Admittedly this is older technology, but since speed is not a major factor in any of these systems, it is not a problem. Also, since all systems are compatible, it allows for components to be swapped between them in event repairs are needed. This would be important if a failure occured in a critical system at a time when replacement parts could not be obtained.

The DCS system has a maximum of 100 commands available. These are configured by the program into either latched or pulsed outputs based on the need. As currently configured, there are 64 pulsed output and 24 latched. The remainder are not assigned in this version of the program. There are 24 wall mounted pushbutton switches which control the latched outputs directly. This allows a light in a room to be turned on or off by a switch near the door much as you would a conventional light, as well as by a DTMF command from some other location.

The pulsed outputs are generally used to control other devices such as the stereo or speech annunciator systems. Speakers may be selected, inputs changed, or messages accessed from remote locations. Certain areas are denied access from some source locations, for instance, it is not allowed to control the stereo speakers from locations where the stereo has no presence. The program uses look-up tables for reference so it is possible to revise a function's allowed access at any time it is desired.

The Telephone Control System

The telephone control system provides several features which improve the versatility of the phones in the house. As with the other systems, it is integrated into the overall electronics package and is used in conjunction with them.

The system is based on the 8085A processor, since it is advantageous to keep all systems hardware compatible with each other. Admittedly this is older technology, but since speed is not a major factor in any of these systems, it is not a problem. Also, since all systems are compatible, it allows for components to be swapped between them in event repairs are needed. This would be important if a failure occured in a critical system at a time when replacement parts could not be obtained.

The phone controller allows the phones to operate in both local and line modes. This allows a conversation to be conducted between extensions, with the system still accepting incoming and outgoing calls from other extensions at the same time. A paging feature is also available. This allows using any extension to page using the voice annunciator speakers. It is useful to call someone else to the phone if a call is received for that person. The controller performs all functions necessary to accomplish these operations such as placing the line on hold if the outside line is active and blinking the line indicators to show the current system status. A Hold feature, similar to that commonly found on telephones is also provided to allow one to take a call on a different extension.

The phones can also be turned off to incoming calls while still allowing those with a priority access code to get through. If the system receives a call while it is in this mode, the caller will be answered with a recorded message telling them to enter their access code. If they do so, the phone controller will activate a recorded message on the VoiceTrax system which will be given over its annunciator speakers stating that a priority call is coming in. The call can then be answered. If no valid code is received, the system will advise the caller that they failed to send the proper code and will disconnect them. In either case the caller ID will log the call for future reference.

Another feature is what I call the Telemarketer's Nemesis. This little gem allows one to fight fire with fire. We all have stuff around the house we'd like to get rid of if we could just find a sucke--I mean a buyer, right? So consider this option...
Telephone rings just as I sit down to eat. Goes something like this:

• ME: "Hello"
• TELEMARKETING PEST: "I'm from the Sky Blue Company and I'm calling to offer you a one time chance - -"
• ME, cutting them off mid-sentence: "Stop right there. Before you go on there is something you need to hear."

The VoiceTrax Message System

The VoiceTrax System is the message annunciator which advises of various conditions around the house. It uses a phoneme based speech synthesizer chip to generate messages related to the device which has activated it. This could be anything from a power failure, to someone at a door, to the mail or newspaper arriving, or maybe the washer has finished a load of clothes.

The system also will route the messages to certain areas where they are needed and inhibit them from areas where they are not. Messages have three levels of priority. Those critical messages, like a fire alarm for instance, are spoken continuously until the condition clears. Others of a lower priority will be spoken once each time they are requested. Still lower priority messages are not spoken at all, but are only stored for later recall, as are all messages regardless of priority.

The recall function is controlled from the Digital Control System. This allows the status to be checked from any location around the house, or also accessed from an outside phone line. This is very useful when away on vacation. The status of things back home can be checked from any DTMF phone anywhere by entering the access code and requesting message recall. The VoiceTrax system will repeat any message it has given from its memory. Once the messages have been heard, the memory may be cleared and a new series of messages begun. Any condition which is currently in play results in a "locked-in " message. These can also be checked separately to differentiate between current conditions and past events.

As with the other systems, this one is based on the 8085A processor, maintaining compatibility between this and other systems in use.

NOTE: Plans for this Power Source are provided on this Website

Uninterruptible Power Source

All control systems in use require 12 Volts DC to operate. This was done to allow a standard 12 Volt battery to provide backup should the commercial power fail. Because of the critical nature of maintaining power to the systems, there are two 12 Volt Uninterruptible supplies in the system. At any given time only one is in operation; the other is there as a backup.

The supplies are configured as an on line UPS. This was done to eliminate transfer time when commercial power drops. Normally the supply provides power directly to the load and to charge the battery. When power fails, the battery is on line and immediately picks up the load. An additional duty of the UPS is to provide an auxiliary 12 Volt output for emergency lighting. This output initially turns on all emergency lights. These lights are then controlled by switches located on them.

The UPS will continually monitor the battery voltage. If it drops below 10.5 volts, the emergency lights will be disabled and the speech system will be requested to give the "Low Battery" warning. In normal use, on a fully charged system, this would occur after 2 - 3 hours. Once running at this reduced demand, the other systems would continue to function for about 6 hours until the battery voltage dropped to 8 volts. At this time a watchdog processor will initiate a graceful shutdown of each system, saving data to allow for restart once the main system is repowered. The watchdog system only requires a few milliamps to maintain operation, so even a mostly depleted battery will provide for its needs for several days. Once power is restored, the UPS will recharge the battery and provide power for the other systems. Usually about 48 hours is needed to bring the battery to 90 percent of capacity if it has been fully discharged.