RFID-Based Road Guiding Cane System for the Visually Impaired

I was leading an inter-disciplinal team to design a smart cane for the visually impaired. With the road guiding cane reading the RFID labels, the visually impaired can locate themselves, be aware of traffic light signals, and find business information near them on the road. This cane was tested with real users for its effectiveness.


Summary

The RFID-based road guiding cane is a navigation system especially designed for the visually impaired. Geographic location, traffic light signals, and business information are saved in a series of RFID labels constructed beneath the sidewalk. With the road guiding cane reading the RFID labels, the visually impaired can locate themselves, be aware of traffic light signals, and find business information near them on the road. After users set the destination, the cane automatically directs the routes for users via voice by specifying the current location and keeping track of previous locations.

Compared with the Global Positioning System, the RFID-based road guiding cane system is more reliable, more accurate, cost-saving, and versatile in providing precise location-based services for the visually impaired.


Background

Transportation safety can be a major issue for many people, especially those who are visually challenged. They could find themselves in very dangerous situations once they become lost and fail to receive help. Business information is also of great importance for them. Without knowing the surrounding environment, many people can have trouble finding shops or even a toilet when away from home on the road. Because few location-based services are often provided, the activity scope of the visually impaired becomes highly restricted.

Feb. 2012 - Feb. 2013


Team

5 Industrial Engineering students, 1 Art & Design student, 1 professor


Responsibilities

  • Team leader
  • Preliminary idea generation
  • User requirements gathering and analysis
  • Preliminary function designs
  • High-fidelity prototype (C) development and testing
  • User evaluation with real subjects
  • Paper writing and presenting in HCII2013
  • Participation in the competition "Challenge Cup", Tsinghua University, 2011


Process

USER REQUIREMENTS GATHERING: AN INTERVIEW

User requirements gathering through an interview

In December 2011, we conducted interviews with 10 visually-impaired people (8 males, 2 females; ages: 53 to 74) to learn about the transportation difficulties they encounter in real life. The subjects were interviewed at a social welfare organization called “Hong Dandan” in Beijing China. From the interview it was found out that visually-impaired people had three main difficulties in their lives:

  1. Turn-by-turn navigation from location A to location B
  2. Going back home when getting lost
  3. Acquiring business information on the street (e.g. finding a restaurant, a supermarket or a toilet)

Among those subjects,

  • 9 of 10 expressed their needs for a navigation cane
  • 8 of 10 preferred the cane with a function to report traffic-light signals

And this has shed lights on the development of a new cane system.


SYSTEM DESIGN AND DEVELOPMENT

Navigation Mode

  • Location and business information are previously stored in the RFID tags
  • According to the type of tags discerned, the cane provides a real-time navigation, or presents the business information to the user


Traffic-Lights Signal Mode

  • Dynamic information in the tags is changed from an RFID transmitter connected to the traffic lights
  • This information about signals is discerned by the cane accordingly and voice messages are prompted


Obstacle-Detection Mode

  • A tag with obstacle information content will be sticked onto any obstacles
  • When the user comes nearby, his cane will read out this obstacle information and give him an alert


USER EVALUATION

6 visually-impaired people participated in our experiment which was carried out in a private yard to ensure their safety. The inclusion of the RFID cane (with the RFID cane, with a normal cane), and the type of tasks (navigation, traffic-lights signals, business information) were selected as independent variables, and dependent variables were set as their subjective evaluation related to the ease of use, usefulness, and enjoyment. A 2*3 full-factorial design was performed in the yard where the cane system was successfully setup.

The result of the experiment showed:

  • Evaluation scores of the RFID device were above average, while that of a normal cane were most negative
  • If the RFID cane was compared against the normal cane using a one-way ANOVA, the difference between these two on Ease of use, Usefulness, and Enjoyment were all significant under a significant level of 0.05.
  • If the type of tasks were included in the analysis, the RFID and normal cane had a strong significant difference in terms of Navigation, but a slight difference in the other two tasks, which led us to find more usability issues about them


DISCUSSION & CONCLUSIONS

Compared to the Global Positioning System (GPS), the RFID-based system is better for:

  • More accuracy in positioning
    • GPS: 10 meters (33ft)
    • RFID: 1 meter (3.3ft)
  • Richer functions
    • GPS: outdoor navigation
    • RFID: outdoor/ indoor navigation, traffic-lights signals, business information, obstacle detection, ...
  • Lower costs and easier to update
    • The cost of one UHF RFID tag is less than $0.1 and the road guiding cane is around $100.
    • Tags are easier to update because all information stored inside could be rewritten by a secured RFID transmitter distantly


Learnings & achievements

  • Coordination ability of the whole team on a UCD project
  • How to code C program with given hardware/ software APIs
  • Basic knowledge of RFID, Bluetooth, and Single-Chip Unit
  • 1 EI-Indexed conference paper published in HCII2013
  • First Prize of 29th Tsinghua Challenge Cup Competition (04.2011)


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© Chen Liao, Last update on May 19th, 2017