Hong Kong students show off ‘Guide Tag’ app for visually-impaired at Joint School Science Exhibition 2019


The STEM enthusiasts from St Mark’s School built an application that measures the distance between objects via radio-frequency identification

Nicola Chan |

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(From left) St Mark's School students Boll Choi, Samson Wu and Kyle Hung were second runners-up at this year's Joint School Science Exhibition.

Samson Wu Chak-tin’s stroke of brilliance came one ordinary Monday evening while he was watching RTHK’s public affairs programme Hong Kong Connection. The episode explored the challenges that people with visual impairments face every day in Hong Kong. As Samson watched, the 19-year-old decided he needed to do something.

He recruited two of his St Mark’s School classmates, Boll Choi Chi-long and Kyle Hung Ka-hei, both 17. Together, they created Guide Tag, an app that allows people with impaired vision to enjoy indoor activities by themselves.

The app proved a huge hit at the Joint School Science Exhibition, held at the Hong Kong Central Library last month.

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The annual exhibition, co-organised by Hong Kong Science Museum and the Leisure and Cultural Services Department, invites students to showcase scientific innovations inspired by a particular theme. This year’s theme, “Journey”, required students to focus on improving the public’s travel experience. The boys came in third place for their app, while the first and second prize went to St Joseph’s College and Salesian English School respectively.”

“White canes can only help the visually impaired to avoid [road] obstacles, and guide dogs must be trained to guide them to certain places. But Guide Tag would make it possible
for people to visit a new indoor environment, such as a shopping centre or exhibition hall, without assistance,” said Samson, speaking to Young Post.

Students from St Mark's School explain how their app works to Joint School Science Exhibition judges.
Photo courtesy of Szeto Ka-yee

The app uses radio-frequency identification (RFID) to work out the location of the user, as well as any obstacles in their path. When the distance between the person and the obstacle is less than two metres, the app sounds out an alert via a text-to-speech message.

Using the strength of the RFID signals to work out the distance between a user and an obstacle caused the boys a lot of headaches, as there wasn’t much room for error.

“We could not copy one of the equations we found online, as it had been formulated for more advanced programmes,” Samson explained.

Although figuring out how to convert the data was “time consuming,” the maths prodigy eventually managed to generate a new equation and apply it to the collected data, using the data assessment techniques he learned in his physics and chemistry lessons.

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Trying to make an app that was totally one-of-a-kind wasn’t easy, either.

“Since the technology we were using has already been used around the world for other purposes, we were really worried that our idea might already exist,” Boll said. “So we spent lot of time researching and formulating our idea.”

The students also had to think about how to best present their product to the judges and the general public. “After listening to the feedback during the official rehearsal before the exhibition, I realised the importance of being able to explain abstract theories in simple everyday terms,” admitted Boll.

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Kyle felt the opportunity to share ideas with university professors was a rare treat.

“We learned a lot from them,” he said. “I remember one suggested that the technology could also be used in AI robots so that they could identify objects, or in car parks to make it easier for drivers to find their cars.”

A number of audience members also showed an interest in Guide Tag, to the boys’ delight. “I was so happy when a father asked us for our contacts so he could learn about the future development of our product,” recalled Samson. “One woman also told us that if the product ever went on the market, her company would gladly invest in one for a colleague who’s visually impaired.”

Edited by Charlotte Ames-Ettridge