Solving Indoor Navigational Needs for a Person with a Visual Impairment (University of Pittsburgh)

Janele Archibald, Hana Casalnova, Josh Singer, Victor Rivera, Jessica Burkman

ABSTRACT

Navigation on campus and in the community is difficult for students with disabilities (SWDs).  Once overcoming this challenge, they still face many disadvantages especially in STEM related classes.  The classes lack the assistive technology (AT) necessary for SWDs to fully participate in the hands-on activities required for learning. One such area of concern is the workshop where safety is of paramount importance and even more crucial for people with visual impairments.  The mission of this client-based project was to develop a navigation system that allows for universal workshop access and learning. Based on client feedback, user needs and specifications were defined. The solution designed to meet these specifications integrates Estimote’s Bluetooth Low Energy beacons and an iOS application. The navigation system, implemented in the University of Pittsburgh’s workshop, guides individuals with (or without) a visual impairment and provides machine specific information. No longer is the workshop a place that the client avoids, and his curiosity about the machines is satisfied.

BACKGROUND

Education in the fields of science, technology, engineering and math (STEM) includes many hands-on learning activities. Unfortunately, students with disabilities (SWDs) are at a significant disadvantage with STEM learning. Many schools, universities, and other facilities are not properly equipped with AT that will enable SWDs to participate fully in activities even though legislation exists that requires SWDs to have equal access to education [(1)]. The goal is to design systems and products that allow SWDs and any other student to engage in hands-on learning.

Specifically, the workshop could benefit from the implementation of universal design principles.  Fabrication is a fundamental part of many engineering design courses, but a workshop is filled with dangerous equipment.  Safety is crucial, and many aspects of the workshop are currently inaccessible to students with disabilities, especially those with a visual impairment like the client involved in this project.

Problem and Need Statements

Although workshops are areas where important educational and learning activities occur, they are largely inaccessible to those with disabilities. In particular, navigating through a workshop to reach a particular location or technology is very difficult and potentially dangerous for visually impaired individuals.

There is a need for a solution which will enable universal access to workshops, as well as other lab environments, and equal opportunity for educational experiences while also providing a unique learning experience that will increase skills and knowledge.

METHODS

Client-Centered Design

A client centered design approach is important in developing AT. By gathering client feedback regularly throughout the design process, the end product is more likely to be useable and meet specific user needs, and less likely to be abandoned. There are numerous physical limitations that arise from disabilities, making a client-centered approach crucial in developing AT.

In our design, client feedback directed us toward aspects of the navigation system that were not initially considered. For example, additional features were added such as textured floor tape to mark important intersections and areas in the workshop, and an initial safety training to alert the user to potential hazards and risks [(2), (3)].

User Needs and Specifications

The needs finding process consisted of regular client feedback to ensure the client’s concerns and suggestions were accounted for in the design process. Feedback was gathered at regular intervals from the client and user needs were developed through client, classmate, and professor feedback.

Table 1. User needs and corresponding specifications. Measurable specifications were developed to test the degree to which the navigation system met the user needs

After finalizing the list of user needs, specifications for the navigation system technology were developed. The specifications include metrics to explicitly characterize a system design that meets the user needs.  The performance of the design was validated against these specifications (Table 1).

System Design

Based on the user needs and specifications, a system integrating Bluetooth Low Energy (BLE) beacon technology and an iOS application has been developed. BLE beacon technology has been used for applications such as indoor positioning systems, and can enable a bluetooth capable device to perform actions depending on its proximity to a beacon. The beacons used in this project were purchased from Estimote, Inc. The beacons are strategically placed throughout the workshop and communicate with the user’s smartphone. The system incorporates two main features: navigation assistance and machine/equipment learning. The navigation assistance provided by the system exists as contextual and navigational cues that are presented based on the user’s position in the shop; however, complete navigation through the workshop for a visually impaired user is dependent on an initial training of the routes and destinations in the workshop. Such an initial training for a visually impaired individual is typically performed by their assistant for any new/unfamiliar area. Machine/equipment learning occurs once the user has reached their destination. For the scope of this project, a proof of concept prototype includes navigation to and learning of the following destinations in the workshop: wire EDM, technical computer lab, laser cutter, and rapid prototyping (3D printing) room. These machines and areas were chosen due to their relative safeness for people with visual impairments to use. Thus, if individuals could safely navigate to these locations, they could actually use these pieces of equipment.

Estimote Beacons and Workshop Layout

The workshop was divided into three regions, containing the four destinations. Seven beacons were placed throughout the workshop and assigned as either a region or destination beacon. Figure 1 shows the layout of the workshop and regions, as well as the placement of the beacons. The yellow circles indicate a destination beacon while the red circles indicate a region beacon.

Figure 1. Workshop layout including regions and beacons

User Interface/Use Scenario and Software Design

Upon entering the workshop and opening the application, the user interface (UI) presents a home screen displaying the destination options. Selecting a destination will display relevant contextual overview information, such as where that destination is located in relation to the regions of the shop. Such a scenario is depicted in Figure 2.

Figure 2. UI of home screen before and after destination selection

When the user is ready to navigate through the shop or to their specific destination, they select the ‘START’ button, at which time the application transitions to the ‘navigation screen’ and the device begins to search for beacons. The closest beacon to the device is found, and the navigation screen displays the name and type of that beacon, along with a set of information specific to the beacon including proximity, distance, and contextual/navigational cue. There are three proximity zones for a beacon: immediate (approximately 1 meter or less), near (approximately 1 to 3 meters), and far (approximately greater than 3 meters). If the closest beacon is a destination beacon and the user is at least within the near zone to that beacon, a ‘Learn’ button will also be displayed. When selected, the application will transition to the ‘learn screen’ where educational information specific to the destination is presented. Figure 3 represents a detected region beacon as closest, while Figures 4 and 5 represent a detected destination beacon and associated ‘learn screen’, respectively.

Figure 3. UI when region beacon is detected

Figure 4. UI when destination beacon is detected

Figure 5. UI when learn option is selected

A final feature to note is the application’s compatibility with Apple’s VoiceOver screen reader. With VoiceOver, all text on the interface can be read out audibly, therefore increasing accessibility for visually impaired users.

RESULTS

Feasibility Testing

Feasibility tests were performed to verify the degree to which the system could meet the users needs. The results of the feasibility studies were used to make changes to the system.  Feasibility tests were conducted to ensure the beacons correctly picked up the bluetooth low frequency signals, and the navigation system application detected the correct beacon and proximity zone. Additionally, further feasibility testing was performed to determine the best placement for the beacons in the workshop to reduce interference and allow for the strongest signal. The locational accuracy of the beacons was measured to determine the level of detail which could be provided to the user. The final feasibility testing involved testing the information provided to the user in  the application on an unbiased subject to make certain the navigational cues were provided in the most helpful and clear manner. Based on the results of the testing, the beacons were moved to the most ideal location within the workshop.  Additionally, the directions were made to be more concise and very specific.

Usability Testing

Usability testing was conducted to evaluate how the navigation system would perform in the workshop.  A usability test was designed and performed to determine how the performance of the navigation system varies under different walking speeds. The point at which the beacon detected should change when walking from one beacon to another was identified for each contiguous pair of beacons (labeled as locations of intersection in Figure 6) by walking slowly to eliminate any potential lag in the system – noted as reference points. This was repeated for each location of intersection walking at medium and fast walking speeds, and the distance between the points for each speed and reference were measured, as shown in Figure 6.  A recommendation was made for the walking speed which would achieve the best results based on usability testing.

Figure 6. Location of intersection vs. Deviation from reference point for different walking speeds

Validation Testing

Validation testing was performed to ensure that the design meets the needs of the client as well as meeting the specifications to evaluate the success of the final design. A summary of the validation tests and the specifications that they address can be found in Table 2.

Table 2. Validation tests performed and the specifications they address.

DISCUSSION

Design Evaluation

The system design was customized to the University of Pittsburgh workshop setting by adjusting beacon placement, beacon advertising interval and broadcasting power, the information and training provided, and user walking speed, among other system functionalities. These variables were shown to greatly influence the success of the system. For example, varying beacon placement, including location and orientation, as well as beacon advertising interval and broadcasting power, changed the point at which the application detected each beacon. Additionally, a lag between the detection of beacons became apparent as user walking speed increased.

Testing of the navigation system showed that the system met all of the specifications developed for the client’s user needs.  The proof of concept system proved to be useful in aiding a visually impaired individual with both navigation and learning in the University of Pittsburgh workshop. However, the feasibility and practicality of this  navigation system as it is expanded into further prototypes and additional settings will be largely determined by the design parameters mentioned above.

Conclusion

A navigation system using bluetooth beacon technology was developed to allow our client as well as other individuals to navigate through and learn about a new space. Navigational and directional cues allow the user to determine their position in relation to existing objects, while information provided increases knowledge and understanding of the machines.  Implementation of the system in the workshop allows for universal accessibility and equal opportunity for educational experiences in a STEM environment that was previously largely inaccessible to the visually impaired. This AT will both promote independence and allow users to safely and effectively navigate through a new, unfamiliar space. Although limitations with current beacon technology restrict use to providing proximity awareness, future improvements may provide more detailed location awareness to the user. Future work for this project will aim to further develop the system functionality, accuracy, and reliability, as it relates to the University of Pittsburgh workshop as well as other settings.

REFERENCES

1. Duerstock, B. S., & C. A. Shingledecker, E. (2014). From College to Careers: Fostering Inclusion of Persons with Disabilities in STEM. Science/AAAS.
2. Tapes. (2015, February 22). Retrieved from emedco: http://www.emedco.com/
3.  3M. (2015, February 20). Your Steps Matter. Retrieved from 3M Safety-Walk Slip-Resistant Tapes and Treads:http://multimedia.3m.com/mws/media/224334O/3mtm-safety-walktm-slip-resistant-tapes-and-treads.pdf

ACKNOWLEDGEMENTS

We would like to thank our client, Bobby, for it was a great experience working with him.  We would also like to thank the workshop staff at HERL for accommodating us throughout the project.  Finally, Dr. Jon Pearlman, Dr. Mary Goldberg, Mahi, and all of our classmates have provided valuable feedback and shared their expertise and advice which was extremely helpful for our project.

APPENDIX: BOM

The following table demonstrates the material costs of the system design (Table A1-1).

 Table A1-1. Bill of Materials.