Guiding people with visual impairmentsusing wireless technologies.
A visual impairment does not have to imply total loss of vision. Instead a visual disability can be anything from a non-correctable blurring of the visual field to a limited possibility of detecting light and darkness. Even though total loss of vision is the most commonly considered visual disability, the remaining types can be almost as disabling when it comes to navigation.
There are many projects that have focused on local navigation, as complementary tools to the Hoover cane, i.e., tools that will support the user in finding obstacles and other things detectable through different kind of sensors, such as ultra-sound, laser and infrared sensors. There are many problems involved in this kind of supportive tools, not least when it comes to how the sensors can interact with the user. Sound feedback has the main problem of shadowing other important sounds that will assist the user to navigate in the natural environment.
Another type of navigation tool uses the idea of spatial triangulation, using GPS positioning for navigation outdoors. This, however, has one big problem, namely that it is not as precise as would be necessary for the close navigation, and the GPS signals can also be hidden or reflected by buildings, bridges and tunnels. It is also not enough for indoor navigation.
This proposal takes a slightly different approach to the navigation issue, which can be exemplified by a small example. At the department there are signs written in Braille on the doors. However, not all doors are marked this way, which brings up a certain issue, namely: How can a person find the Braille markers on the doors if they are only available for some of the doors? In the initial idea gathering for this project, one possibility was to use rFid tags and trackers, that can be proactive, both notifying the user about the existence of a tag, and even provide content stored in the rFid tagging.
With this as a starting point we in this project proposal suggest an initial investigation of the practical usability of different wireless technologies as supportive tools for semi-local localization and/or the acquisition of publicly available information such as room numbers, but also for other more complex information, such as the bus traffic at a certain bus stop.
It is possible that this kind of tool will make use of several technologies, but here are some important factors that will influence the design:
- Maximum distance for detection
- Energy requirements, both for user and sender
- Precision in location detection
- Information density
- Dependence on wireless information, either by mobile network or wi-fi
- Degree of lagging
- Local or Cloud storage
All these factors will of course influence the final design of the device, and the goal of the project is to provide a first prototype or proof of concept, where the actual usability, in terms of size, communication manner and accessibility will be of secondary importance.
The project work will be constituted by two main parts:
- A literature study about wireless techniques and their suitability (according to the properties above.
- An implementation of a prototypical device, where we can use microcontrollers (e.g., Arduino boards) in combination with sensors to show how this kind of device could be implemented and used. In case this becomes too large, we can also implement the prototype partially, as a demonstrator.
Necessary electronics and similar material will be provided by the department within reasonable limits.
The project will be positively supported by knowledge (courses) about:
- Programming in C (Arduino) and Python or Java.
- Human-Computer Interaction studies
- Wireless and wired data communication techniques
- Basic electronics
- Navigation techniques (e.g., principles of GPS navigation)
- Some knowledge about visual impairments.
Unification of Ideals
Figure 1. The user is walking along the corridor. At each door opening there
is a mounted beacon combo, which uses open bluetooth connections to be visible to the user’s application (blue lightning). Each beacon has it’s own identity, and contains a small amount of information about its location, such as room number, office owner, etc. The bluetooth beacon would also be able to send its physical location (to the left or the right of the person’s path in the corridor), this information can be used by the user application to determine (depending on which direction the person is moving physically) to give the user a hint about which direction to go. Signal strength might provide a possibility to determine the distance. This situation changes when the user comes closer to the beacon, and…
Figure 2. … the Bluetooth beacon is replaced by an RFID (or QR-code on the wall). This short range locator (pink lightning) can then be used to provide the user with sources to additional information about the location, and provide a link to other accessible information sources (this might be more interesting in case this is used for more advanced location services, such as bus stop information etc.
If the location is outside of a building the Bluetooth connection could be complemented by a GPS-driven map application that keeps track of all the servers. The GPS is, however, not fine-grained enough to be able to let the user find the exact location of the information source.
This extension in functionality will not be part of the current thesis work.
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