A COMPUTER-BASED ENVIRONMENTAL CONTROL SYSTEM

Richard Simpson, Glen Ashlock, M.S., and Simon P. Levine, Ph.D. Rehabilitation Engineering Program University of Michigan Medical Center

ABSTRACT

A new environmental control system (ECS) has been developed which, based on clinical experience, satisfies a previously unfulfilled need of many clients. The University of Michigan ECS (UMECS) is a computer-based ECS which is flexible, inexpensive, and easy to use. This paper discusses the design of UMECS along with its advantages and underlying design criteria.

INTRODUCTION

Computer-based ECS's have several advantages over their stand-alone counterparts which they derive from the power of the computer they inhabit. A primary advantage computer-based ECS's enjoy is a dynamic display, which provides tremendous flexibility. Dynamic displays can change based on the operation that the user is carrying out, which simplifies both the user's interaction with the system and the design of the system's interface. Dynamic displays are also capable of changing to accommodate the specific needs of a user. Additionally, they allow graphic user interfaces, which make a program easier to understand and learn how to use. For example, a computer display can vary between word-based and picture-based representations or switch to extra-large print. While these changes are conceivably possible to implement on a stand-alone ECS with a dedicated display they are often ad-hoc in nature and difficult to optimize. The computer's disk drive allows a computer-based ECS to provide the ability to store backups of environmental control system information permanently. This means that a sudden loss of power will not erase all of the data stored in the ECS, which can happen to a stand-alone system without a battery backup feature. A computer-based system can make use of equipment that the client already has or will be purchasing to meet other needs. In such a situation, the addition of a few inexpensive environmental control devices represents a minimal cost for a complete ECS. In addition, for clients that spend much of their time in front of a computer, an ECS that is integrated with their computing system may represent the most accessible location for centralized control of their environment. Another advantage of computer-based ECS's is that for many people it is easier to obtain funding for computer systems than environmental control equipment, because computers more clearly represent an opportunity for pursuing educational or vocational opportunities. ECS's, on the other hand, are often times difficult to justify to outside funding agencies, leaving individuals with the responsibility of purchasing environmental control equipment on their own. Of course, a computer-based ECS is not a viable solution for everyone, particularly for those that do not own, or wish to use, a computer. If the ECS is integrated with the computer, a breakdown in the computer means losing both the computer and the ECS. A computer-based ECS, like many stand-alone ECS's, is not conducive to mobile operation. However, it is certainly possible that remote control similar to that available for some stand-alone ECS's could be developed for computer-based ECS's. For those individuals that desire the ability to control devices from several different rooms of their house, the most reliable solution currently remains to be the use of a smaller, mobile unit.

BACKGROUND

A variety of different computer-based ECS's have been developed over the years, and a complete review is not possible in the space allotted. However, a select few can serve as a representative sample of the field as a whole. The Eyegaze System [1] provides environmental control and communication capabilities to individuals while only requiring consistent eye movement for input. While impressive in its capabilities, this system is extremely expensive and exceeds the budgets of most people. The X10 Computer Interface [2] sits at the other end of the spectrum, in terms of both functionality and cost. The interface is inexpensive, but its accompanying software is limited, only providing access to the X10 Computer Interface, which constrains the control options which are available. The Cintex computer-based ECS [3] is characteristic of many mid-priced computer-based ECS's. This system offers both infra-red (IR) and X10 control options and fairly sophisticated control capabilities. Unfortunately, while a great deal of design effort was devoted to the system's functionality, Cintex does not take full advantage of a computer's ability to reduce the complexity of a task. Other systems, while presenting unique advantages, also suffer certain drawbacks. Some limit the user's ability to run other applications (spreadsheets, word-processors, etc.) while the ECS program is active. Others do not interact smoothly with the user's computer access method. Still others are too complex for an individual to install and support without extensive assistance.

STATEMENT OF THE PROBLEM

Based on our clinical experience, we felt there was a distinct lack of a system which was both flexible and powerful enough to meet the needs of many different clients while remaining sufficiently inexpensive that it could be purchased without significant outside funding. Our solution to this problem was to construct an ECS from a collection of inexpensive components and use a computer to provide a uniform method of accessing all of these disparate parts.

DESIGN CRITERIA

The most important criterion was that the ECS work with all of the different access methods that our clients use. These included mouse emulation, voice recognition, Morse code, and one and two switch scanning. The system also needed to be simple to operate and support. For many clients, the computer we recommend is the first computer they ever receive. Neither they, nor their families, are prepared to provide extensive technical support for a computer system and they sometimes live too far away to receive frequent home visits for assistance. In addition, reducing the required amount of technical assistance also decreases the overall cost of the ECS by minimizing the amount spent on installation and support. Another stringent requirement was that the ECS software not interfere with the user's ability to use the computer for other tasks. Ideally, the system would run in a multi-tasking environment, allowing the user to switch back and forth between other applications and the ECS easily. In order to meet the needs of as many different clients as possible, the system needed to be highly flexible and configurable. The program could not limit the person to one television, or require that they sift through the controls for a stereo if they did not own one. The ideal system would allow the user to specify exactly what items were present in the environment that needed to be controlled and would only present the user with control options for those things. Finally, the ECS had to be inexpensive. This included the software, the additional hardware that came with it, and all technical support. For most people, the reason they were pursuing this avenue of environmental control was a need to keep costs at a minimum.

APPROACH

The design of our new computer-based ECS, UMECS, was guided by feedback from rehabilitation engineers familiar with environmental control and is currently implemented for the Windows operating system. The program was written for the Windows operating system for several reasons. The majority of all IBM-compatible PCs come packaged with Windows and most new software being developed for the PC is aimed at running within the Windows environment. There exist several different computer access methods available for use with Windows including the recent addition of voice recognition, which is used by many people. Windows also offers the distinct advantage of being a multi-tasking operating system. This allows a computer user to switch easily between UMECS and other programs without having to terminate one application to begin another. UMECS was written to require very little computer memory, in order to keep the maximum amount of computer resources available to run applications and the user's computer access method. Thus, at any time, UMECS can be placed in the background while the user runs other applications. There are a myriad of controls available for Windows programs, including scroll bars, buttons, and "speed bars." Unfortunately, only a few of these are accessible to an individual who is not using a mouse or mouse emulator. The only control objects included in the user interface were those that could be operated with both the keyboard and the mouse. This allows any user with a functioning computer access system to operate UMECS without the need to construct elaborate access schemes to use any of the program's functions. UMECS was written in C++ and compiled using the Borland C++ 4.0 compiler. Many of the advantages that UMECS enjoys are a direct result of an object oriented programming approach; the flexibility of the system is derived from the ability to treat every electrical device to be controlled as an independent object within the program. In addition, creating the user interface was also greatly simplified through the use of object oriented programming. Three very flexible control components have been integrated into UMECS: the OneForAll programmable infra-red remote control [4], the X10 Computer Interface, and the Prenke Romich Scanning Director [5]. The OneForAll and the cable needed to attach it to the computer sell for less than $100 and can provide control over any infra-red remote-controlled device that the user owns. The Scanning Director is a trainable remote control that has the added advantage of offering switch access when not operated via computer. Through the X10 computer interface, a user can control power to any appliance that plugs into an electrical outlet (e.g.: radio, lamp, fan). The variety of X10 control modules which exist makes UMECS extremely flexible. The user interface was kept as simple as possible, which reduces both learning time and the complexity of using the program. Each device that the user wishes to control has its own "virtual remote control." Adding a new device is as simple as adding another "remote control." Because each device is considered separately from the intermediary hardware that is actually controlling it (i.e. - the OneForAll, Scanning Director or X10 Computer interface) the remote control that is presented to the user on the computer screen is tailored to the specific control options of its corresponding electrical device. Thus, for example, even though the OneForAll has a static keypad which must be general enough to incorporate the control options of all the different possible units that it can operate, the specific control options that the user chooses from when using the computer-based ECS are limited to those that are specifically applicable to the device being controlled.

DISCUSSION

The UMECS user interface offers several advantages when compared to an ECS with a static display. First of all, the display is greatly simplified. Only those options that are active are displayed at any time. Furthermore, it allows a flexible "plug and play" approach to environmental control. In order to add a new device to UMECS one simply plugs it in and then creates a virtual remote control within UMECS. To create the remote control the user specifies the type of device that is being controlled and the program automatically produces a remote control for it. UMECS does not limit the user to a pre-determined set of electrical devices that can be controlled. The user can add as many devices as the hardware attached to the computer is capable of controlling. And, if the user does not need all of the control options these components offer, he or she does not have to scan through unused commands to reach the desired ones. The flexibility of the program is enhanced by the possibility of multiple program configurations, each stored as a data file within the computer. At any time, the user can choose to load a file containing a set of appliances to be controlled or can start a new set. The user can use any number of different files, which allows the system to be quickly configured for different needs. UMECS has been used succesfully by two of our clients. The first took full advantage of all its features and controlled lights, his television, and his stereo with the system. The second client uses UMECS to operate X10 devices in his home.

FUTURE DEVELOPMENT

UMECS as it exists now is a fully functional ECS. However, in order to increase its usefulness, several enhancements are planned, the bulk of which will be aimed at increasing the program's flexibility. Obvious improvements include adding to the number of environmental control components that UMECS can interface with. Other areas of the program that could be expanded include the variety of interfaces that the program is capable of presenting to the user; interfaces that are picture based or use very large lettering would increase the number of people able to use UMECS. Finally, UMECS will not be complete until it fully addresses the issue of phone control. Currently, UMECS can be used to operate a switch controlled telephone, but in most cases this limits the user to answering and hanging up the phone and dialing the operator. One option is to take advantage of the built in phone-dialers that come with many computers, which is fine if the user's access method can operate the software supplied with the computer. Another method, which we are investigating, is to use a modem to operate a speaker phone. Many computers come equipped with modems at the time of purchase, so the added cost to a user would be limited to the price of a speaker phone. UMECS has been very successful meeting the needs of two clients, and is applicable to the needs of even more individuals. This, coupled with the anticipated addition of the improvements discussed above, cause us to envision many more users for UMECS in the future.

REFERENCES

Eyegaze System, LC Technologies, Inc., 9455 Silver King Ct., Fairfax, VA 22031.

X10 Computer Interface, X10 (USA), Inc., 185A Legrand Avenue, Northvale, NJ 07647

Cintex, NanoPac, Inc., 4833 South Sheridan Road, Suite 402, Tulsa OK, 74145.

OneForAll, Universal Electronics, Inc., 1519 Enterprise Parkway, Suite H, Kent, OH, 44240.

Scanning Director, Prentke Romich Company, 1022 Heyl Road, Wooster, OH 44691

Richard Simpson Rehabilitation Engineering 1C335 University of Michigan Hospital Ann Arbor, MI 48109-0032 Computer-Based ECS