Issue 2/2009


03/02/09

RFID Technology & Elevator

A New Concept in Increasing Elevator Functionality and Accessibility for Disabled People

Leontios J. Hadjileontiadis
Radio Frequency Identification (RFID) is evolving as a major technology with growing number of users. Initially it has been used to track goods and assets in retail, manufacturing, hospitals and storage systems, but it has evolved to have many applications outside these areas. RFID is the technology behind car keyfobs, public transportation access (such as the London Transport Oyster card), ski resort lifts passes, distributed spatial sensory systems, security badges for access control into buildings, etc. The field of elevator seems to be a potential area for the integration of RFID technology towards the increase of its smartness and the provision of appropriate information, especially to disabled users. The proposed work describes the characteristics of the RFID technology and presents some of its applications, combined with its potential use in elevators for assisting people with disabilities, i.e., blind people, to function and access them more efficiently.
Category: Issue 2/2009
Posted by: Editor

1. Introduction

New technologies have opened up exciting possibilities for making life easier for people with disabilities. At the same time, new technologies have had a major impact on society as a whole. For instance cash dispensers and mobile phones are now widespread and other new technologies such as interactive television, smart cards and satellite navigation systems are likely to have increasing market penetration in the next few years. Unfortunately, many of these new systems are difficult or impossible to use by someone with disability, e. g., a serious sight problem, unless their needs were considered when the system was designed. In the area of user interface design, good design for people with disabilities is often good design for everyone (Gill, 2007).
From the above perspective, several initiatives have been proposed in the literature, as technological assistance to disabled people, involving a variety of technologies in their design and implementation. For example, in the case of blind people, Golledge et al. (1991), Strothotte et al. (1996), Ran et al. (2004), Kitsas et al. (2006) proposed the use of Geographical Information Systems and/or Global Positioning System (GPS) information for outdoor navigation. Especially in Kitsass et al. (2006) work, the navigator is combined with a mobile phone, both voiced-handled, facilitating the user friendliness and functionality.
Some other approaches (Piotrowski, 2003; Kulyukin et al., 2004) propose the usage of Radio Frequency Identification (RFID) passive tags for navigation system for blind people. RFID tags provide location markers and a mobile receiver provides user navigation information based on the code stored in each tag. These system do not require a power supply for location markers and overcomes the GPS navigation limits in indoor environments. On the other side, the tags placement cost could be high and usually tags are not easy to adapt for an outdoor, harsh environment.
In general, RFID is evolving as a major technology enabler for tracking goods and assets around the world. It can help hospitals locate expensive equipment more quickly to improve patient care, pharmaceutical companies to reduce counterfeiting and logistics providers to improve the management of moveable assets. As a result of the potential benefits of RFID, many of the worlds major retailers have adopted RFID tagging for pallets and cases shipped into their distribution centers, fueling the market for hardware and software to support RFID. Some surprisingly familiar RFID applications outside of the retail supply chain include car key-fobs, mass transit (e. g., the London Transport Oyster card), ski resort lift passes and security badges for access control into buildings. It is often described as a transformational technology in terms of its potential impact on business processes and systems. However, in many ways it is a logical evolutionary step on from the barcode as a way of gaining increased labor productivity through automation. When used in conjunction with allied technologies it can remotely sense objects to determine their identity, track their position and detect properties such as pressure and temperature. RFID equipment has steadily fallen in price as volumes increase and microchip unit production costs fall. With the ability to store several k bytes of data in addition to the number plate identifier it could be viewed as a form of mass distributed database that has the potential to become ubiquitous – billions of tags in daily use throughout the world on all objects that are produce d, stored, moved, sold and maintained.
In the past, access to public buildings has been extremely difficult, if not impossible, for many disabled people and in particular wheelchair users. Elevators can help to provide access to stores above or below the main entrance level of a building. If designed appropriately, elevators are the most convenient form of vertical access for disabled people. However, the functionality of the elevator seems to provide ample space for expansion, involving more flexible technology, like RFIDs. So far, only sporadic approaches towards this direction have been reported, like that of Naohiko et al. (2004), who developed an elevator system that detects and recognizes passengers and controls car calls, with RFID and stereo camera.
In this paper, the characteristics of the RFID technology are described, combined with its potential use in elevators for assisting people with disabilities, i.e., blind people, to function and access them more efficiently.
2. RFID technology
RFID is a general term that is used to describe a system that transmits the identity (in the form of a unique serial number) of an object wirelessly, using radio waves. This is sometimes referred to as contactless technology and a typical RFID system is made up of three components: tags, readers and the host computer system (RFID Center, 2008).
RFID technology & elevator: A new concept in increasing elevator functionality and accessibility for disabled people.
2.1 RFID Tags
An RFID tag is a tiny radio device that is also referred to as a transponder, smart tag, smart label or radio barcode. The tag comprises of a simple silicon microchip (typically less than half a millimetre in size) attached to a small fl at aerial and mounted on a substrate. The whole device can then be encapsulated in different materials (such as plastic) dependent upon its intended usage. The finished tag can be attached to an object, typically an item, box or pallet and read remotely to ascertain its identity, position or state. Characteristic examples are illustrated in Fig. 1.
2.2 RFID Readers
The reader (see Fig. 2), sometimes called an interrogator or scanner, sends and receives RF data to and from the tag via antennas. A reader may have multiple antennas that are responsible for sending and receiving radio waves.
2.3 Host Computer
The data acquired by the readers is then passed to a host computer, which may run specialist RFID software or middleware to filter the data and route it to the correct application, to be processed into useful information (see Fig. 3).
2.4 Flexibility of RFID
RFID technologies are grouped under the more generic Automatic Identification (Auto-ID) technologies. Examples of other Auto-ID technologies include Smartcards and Barcodes. RFID is often positioned as next generation barcoding because of its obvious advantages over barcodes. However, in many environments it is likely to co-exist with the barcode for a long time. Nevertheless, barcode labels have several limitations:
  • low storage capacity
  • they only represent a series of items and not an individual or unique item
  • durability (as mostly printed paper)
  • low read range
  • they can only be read when line of sight is established
  • they can only be read one at a time
  • they cannot be written to or reprogrammed
Rather than using light to collect or read a number from a bar code, radio waves are used to read a number from the RFID tag. RFID therefore does not need line-of sight to operate.
Using radio means that the tag no longer has to be visible on the object to which it is attached; the tag can be hidden inside the item or box that is to be identified and still be read. This minimizes or eliminates the need for a person to have to present the reader to the tag as it can now be fixed to a wall for example. As the item is passed by the reader it will be read automatically, thus giving a potentially large saving in labour costs or substantial increase in throughput of scanned items. Another feature of RFID is the ability to read many tags together at once. It is not necessary to present each tag to the reader separately (as is required for barcodes), instead, all tags within the range of the reader can be read almost simultaneously as they pass the reader. Again, there is a huge savings potential in not having to manually present the reader to each item to be identified. Furthermore , data can also be written to the tag, a feature not possible with barcodes. This latter feature has tremendous implications for intelligent systems and the potential benefits of RFID.
2.5 RFID Types
There are several versions of RFID that operate at different radio frequencies. The choice of frequency is dependent on the business requirements and read environment; hence, RFID is RFID technology & elevator: A new concept in increasing elevator functionality and accessibility for disabled people not a technology where one size fits all applications . Three primary frequency bands are being used for RFID (Das, 2006):
  • Low Frequency-LF (125/134.2KHz): Most commonly used for access control, animal tracking and asset tracking.
  • High Frequency-HF (13.56 MHz): Used where medium data rate and read ranges up to about 1.5 meters are acceptable . This frequency also has the advantage of not being susceptible to interference from the presence of water or metals.
  • Ultra High-Frequency-UHF (868 MHz to 930 MHz): Offers the longest read ranges of up to approximately 10 meters (without battery) and high reading speeds.
  • Microwave-MW (2.45 GHz or 5.8 GHz): Offers long range, high data rate and the smallest and cheapest tag, yet evokes health issues, such as permitted microwave dose and public perception.
Lower frequencies have low energy, which means they transmit data more slowly and range is limited. Tag antenna size is typically quite large for best range. However, even though they have a smaller range than higher frequencies they are more tolerant of obstacles, even moderately tolerant of small amounts of ferrous metal in the way. One can flood an area with radiowaves from one or two antennas, avoiding blind spots. High frequencies have more energy and therefore can be used for long range applications. A beam is involved, so it can be used for locating a smart label in three dimensions. Power drops off as the cube of distance for low frequency but only as the square of distance at high frequency. However, these high frequency beams are more easily stopped. They can give problems with reflections, irradiation of humans, aiming beams (flooding an area is less easy), inability to see round corners and problems with blocking of the beam even by some things the human eye can see through. High frequencies, having more energy, have faster data transfers. More recently, companies have developed near field UHF tags, which use a coil for coupling the tag to the reader similar to a HF tag. This makes the UHF tag perform better around fluids and metal, albeit at shorter range of up to 50 cm or so.
RFID tags are further broken down into two categories (RFID Center, 2008):
  • Active RFID Tags are battery powered. They broadcast a signal to the reader and can transmit over the greatest distances (100+ meters). Typically they can cost 7-30 or more and are used to track high value goods like vehicles and large containers of goods. Shipboard containers are a good example of an active RFID tag application.
  • Passive RFID Tags do not contain a battery. Instead, they draw their power from the radio wave transmitted by the reader. The reader transmits a low power radio signal through its antenna to the tag, which in turn receives it through its own antenna to power the integrated circuit (chip). The tag will briefly converse with the reader for verification and the exchange of data. As a result, passive tags can transmit information over shorter distances (typically 3 meters or less) than active tags. They have a smaller memory capacity and are considerably lower in cost (less than 1) making them ideal for tracking lower cost items.
There are two basic types of chips available on RFID tags, Read-Only and Read- Write. Read only chips are programmed with unique information stored on them during the manufacturing process often referred to as a number plate application. The information on read-only chips cannot be changed. With Read-Write chips, the user can add information to the tag or write over existing information when the tag is within range of the reader. Read-Write chips are more expensive that Read Only chips. Applications for these may include field service maintenance or item attendant data, where a maintenance record associated with a mechanical component is stored and updated on a tag attached to the component. Another method used is something called a Write Once Read Many chip. It can be written once and then becomes Read Only afterwards.
2.6 Standards
Standards and regulations are important to ensure safety and the interoperability of tags and readers across national boundaries and between trading partners. A common misunderstanding is that RFID is regulated by one trade body; nevertheless, it is, in fact, influenced by a number of official bodies for different aspects:
  • Frequencies, power levels and operating cycles are regulated in Europe by the European Telecommunications Standards Institute (ETSI) (www.etsi.org).
  • Protocols for communication between tags and readers are proposed by a number bodies and equipment manufacturers. The two most prominent organizations for setting standards are the International Standards Organization (ISO) (www.iso.org) and EPCglobal (www.epcglobalinc.org).
EPCglobal is leading the development of industry-driven standards for the Electronic Product Code (EPC) to support the use of RFID in supply chain applications. This is to ensure that data created in one place can be read and interpreted anywhere in the global supply chain.
3. Disability & accessibility
It is the experience of many who are neither elderly nor disabled, that the technology in our everyday lives is both complex and difficult to deal with. From video recorder and television controls to mobile phones, ticket selling machines, screen interfaces and e-mail systems.
Almost nothing is simple. Most devices are complicated and off-putting. People with disabilities, such as low vision or poor manual dexterity, have long had to deal with devices that have not been designed with their needs in mind. There is now growing concern that the lack of design foresight is creating greater social exclusion. Inclusive design is the keysolution to this problem.
3.1 Inclusive Design
Inclusive design is the design of mainstream products and services that are accessible to, and usable by, as many people as reasonably possible, in a wide variety of situations and to the greatest extent possible without the need for special adaptation or specialized design (Gill, 2004). The number of people with special needs is larger than the number of people with disabilities since it includes children, older people and people who are left-handed. Another significant group is those people who have limited knowledge of the English language; this includes some immigrants as well as foreign visitors. In addition, systems for use by the general public should take into account differences in culture, particularly among ethnic minorities, which may render some designs unacceptable.
3.2 Standardization
For achieving the fusion of the inclusive design of a product, a standardization procedure should be employed, comprising of four phases (Gill, 2004):
  • Deciding what needs to be standardized and finding experts to participate in the work.
  • Writing the precise standard; this requires detailed technical knowledge as well as good understanding of the implications of various impairments.
  • Implementing the standard (i. e., encouraging the key players to take it up).
  • Publicity so that disabled people are aware (e. g., the significance of the tactile danger warning on packaging containing dangerous substances).
4. Towards the smart elevator
Following the concepts presented in the previous sections, some implications that could be applied to the case of the elevator and its functionality, making it more smart and adaptive to the users needs, especially the disabled one, could be proposed. These are defined through specific disability scenarios.
4.1 Elevator Access
4.1.1 Blind or Visually Impaired People
Transferring the notion of RFID-based navigation for the blind or visually impaired people to the area of the elevator, the first similarity that comes to mind is the coding of the area around the elevator using RFID tags. The configurationproposed in the SeasamoNet Project (Medaglia et al., 2007) could easily be adopted in the case of the elevator. In particular, the idea consists in using RFID passive transponders (i.e., microchips) to create a path guiding a visually impaired person through a location; Fig. 4 shows an example of such guidance to the escalator.
From a closer look, the configuration could include embedded RFID tags in the floor that form the path which guides the blind person to the elevator door. These RFID tags could be passive; hence, there is no need for any electric power supply. An antenna (with a Bluetooth transmitter) which detects/reads the RFID transponders could be embedded in the walking stick. Each transponder sends a signal via the antenna to a Smart Phone or Pocket PC, equipped with a database with information on the elevator characteristics. This could relate, for example, to the specific building, floor, area sector, location of elevator door, etc. Through a Bluetooth headset, the user could receive information on the path (e.g., how to reach the elevator door). This procedure is shown in Fig. 5.
When the blind person reaches the elevator, an RFID reader on the elevator side could automatically identify the existence of the user in front of the elevator door, based on an RFID tag that s/he carries (or already embedded at the top of the cane), and could act in an assistive way, like evoking automatic lift call or giving out speech messages with instructions.
4.1.2 Physically Impaired People
For the case of physically impaired people who use a wheelchair, RFID tags could be placed on the wheelchair (near the front wheels) and an RFID reader on the elevator (probably on the door or on the door frame at the floor level). In this case, UHF RFID tags can be used, so the elevator could recognize the early arrival of the wheelchair (at a distance of 1–2 m). In this way, whenever the existence of a wheelchair is identified (see Fig. 6), the elevatorcould automatically be called and be instructed to allow more time and give audible and visible indicators. Consequently, safety in the access of the elevator could be supported.
4.2 Elevator Safety and Use
In a more general perspective of the users safety, two RFID readers could be placed on the internal side of the elevator door (one top and one bottom) and could identify the existence of the elevator movable chamber behind the elevator door. The elevator movable chamber could be equipped with two LF RFID tags (one top and one bottom), so their low range could be used for more detailed evaluation of the existence of the elevator movable chamber at the correct position relevant to the elevator door; when both RFID readers identify the LF RFID tags and sustain their identification above a time threshold, the elevator could activate audio messages that the elevator has arrived and it is safe to be used. Moreover, as an additional option, another UHF RFID tag could be placed on the elevator movable chamber (top) and could be read from the RFID reader placed at the bottom, on the internal side of the elevator door, to monitor the arrival of the elevator movable chamber when reaching the callers floor. In this way, audio information could be provided to the blind or visually impaired user about the forthcoming arrival of the elevator.
Using the information from the users RFID tag, an RFID reader embedded in the elevator movable chamber could detect the presence of a disabled person within the elevator and adapt its functionality, accordingly. For instance, a voice recognition interface could be activated and through simple voice-commands the blind or physically impaired user could handle the functioning of the elevator. In addition, emergency scenarios with appropriate interface could be available in case of a malfunction (e. g., automatic placement of an emergency call to the elevator monitoring center using voice command for the blind, touch-buttons and visual information for the deaf, etc). Finally, RFID tags could be embedded in the elevator floor and could guide the blind user to correctly find the exit (mostly in cases when the elevator entrance is in different direction than its exit).
5. Conclusive remarks
From the examples presented in this paper , it is apparent that the use of RFID technology can increase flexibility, accessibility and safety to the elevator use, providing an easy way to transmit valuable information that could adapt the elevator functionality to the users needs. This is of great importance as disabled people are everyday users of the elevators. Considering the benefits of the RFID technology, its transfer to the area of the elevator, in eneral, could contribute to:
- Decreased Cycle Time and Taking Costs Out
  • Since RFID scanning is not a serial process, like traditional Barcode scanning, identical tasks can be performed much more quickly.
- Reduced Rework
  • As RFID scanning has a greater first time pass accuracy this reduces the number of errors that are generated and retries needed.
- Reduced Business Risk & Control of Assets
  • RFID tagging enables better audit and asset control. The ability to track and trace items better means assets can be located more easily. The opportunity for enhanced data collection leads to increased accuracy of record keeping and improved asset maintenance. Regulatory compliance can be achieved more effectively.
- Improved Security & Service
  • Being able to validate information relating to an item enables increased security. This individual identification contributes to more effective access control, reductions in shrinkage and other losses and the ability to provide fast and efficient services at the point of need. Ability to authenticate information can prevent activities like counterfeiting and fraud.
- Improved Utilization of Resources
  • information obtained by RFID scanning can be used to improve planning. Processes can be improved, time can be saved, assets can be utilized better.
- Exception Management
  • RFID enables processes and procedures to be measured better. Until a process can be measured accurately it often cannot be improved. Decisions that are based on limited, inaccurate, out-of-date information are often poor decisions. The contribution information captured by RFID offers better management.
Clearly, the evolution of the technology has created new options for re-thinking about solutions that have so long been established. The concept of the elevator belongs to such category, as its use as a vertical transportation means goes back to the works of the Roman architect Vitruvius, who reported that Archimedes built his first elevator, probably, in 236 and accessibility for disabled people B.C. Apparently, the trajectory from that original idea to Crispens first residential elevator in 1929 and to the present form of the elevator leaves some space that could be further explored, in order to integrate advanced technological aspects in its functionality, for the benefit of the users practice. As it was described in this paper, such approach could be beneficial for people with deficiency, providing a normalization of the technology to their needs and not vice versa.
6. Acknowledgement
The author would like to acknowledge the support of KLEEMANN HELLAS and especially Mr. Nikos Spyropoulos (Codes & Standards Manager) for his motivation.
References
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Gill, J. (2004). Access-Ability: Making Technology More Useable by People with Disabilities, RNIB, London.
Gill, J. (2007). Accessibility for Visitors, RNIB, London. Golledge, R. G., Loomis, J. M., and Klatzky, R. L. (1991). Designing a personal guidance system to aid navigation without sight: progress on the GIS component. International Journal of Geographical Information Systems, Vol.5 (4), pp.373-395.
Kitsas, I. K., Panoulas, K. J., Kosmidou, V. E., Taplidou, S. A., Saragiotis, C. D., Hadjileontiadis, L. J., and Panas, S. M. (2006). SmartEyes: An efficient mobile phone/ navigator for blind or visually impaired people. Proc. of the Forum for the ICT Professionals Congress (FITCE 2006), Athens, Greece.
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Naohiko, S., Kentaro, H., Masafumi, I., Takuya, I., and Koichi, S. (2004). The Recognition System of Person Movement Based on RFID and Stereo Camera. Joho Shori Gakkai Kenkyu Hokoku, Vol.2004 (112) (UBI-6), pp.9-14 (in Japaneese).
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Ran, L., Helal, A., and Moore, S. E. (2004). Drishti: An Integrated Indoor/Outdoor Blind Navigation System and Service. In Proceeings of the Second IEEE Annual Conference on Pervasive Compuing and Communications (PerCom.04), pp.23–30. RFID Center (2008), www.rfi dc.com
Strothotte, T., Fritz, S., Michel, R., Raab, A., Petrie, H., Johnson, V., Reichert, L., and Shalt, A. (1996). Development of dialogue systems for a mobility aid for blind people: initial design and usability testing. ACM SIGACCESS Conference on Assistive Technologies, Proceedings of the second annual ACM conference on Assistive technologies.
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