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Scratch-built rice harvester major attraction at STEM fair

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Lim Vannarith and the model rice harvester which caught the public’s attention at the exhibition in Banteay Meanchey province on August 16. SUPPLIED

Scratch-built rice harvester major attraction at STEM fair

Among booths showcasing technological items from 98 groups of students at the Serei Saophoan town fair under the theme “Together for Better Future Business”, a 14-year-old boy’s model rice harvester received a lot of appreciation from the public. He was widely praised for the way he had constructed it entirely from discarded scrap material.

Grade 8 student Lim Vannarith – from Prey Russey village, Sangkat Preah Ponlea, Serei Saophoan town – used hard paper, foam, radio, a remote controlled toy car and some skewers to make the harvester, at a cost of around $10.

“I used discarded items like cardboard boxes and skewers as they were very cheap. I built the engine using a dynamo from a discarded radio and the remote control from a toy car. The only parts I needed to buy were the battery and a sensor,” he explained.

His team had four members. His older sister decorated the harvester, while two other students collected the materials. Vannarith was the one who assembled the project and made it work. He explained that he was drawn to the project because he had seen how much of a contribution agricultural machinery had made to local farmers.

Chhou Bunroeung, director of the Banteay Meanchey provincial Department of Education, Youth and Sport who organised the 2022 STEM Fair (science, technology, mathematics and engineering), held on August 16 – said the fair was to showcase the work of 98 groups of students and the topics related to STEM (Science, Technology, Engineering and Mathematics).

He said that because of Vannarith’s use of discarded items, his work had received a lot of attention.

Bunroeung, who spent over two hours visiting all of the booths at the fair, told The Post: “We initially planned to show the work of students from 10th to 12th grades, but we ended up including some projects from 8th graders, too.”

He stressed that all of the inventions were closely related to physics, chemistry and mathematics. Public and private schools contributed teams, with sponsorship coming from Coca-Cola and various electronics companies.

“We predicted that about 4,000 people would see the fair, but in the end more than double that attended. We encouraged young people from Serei Saophoan town to join, as we felt that traffic safety concerns meant in may be dangerous for students from further away to travel to the fair,” he said.

Vannarith spent from one week to 10 days to build his harvester, utilising his spare time outside of school to work on it.

“If I had been on vacation, I would have completed it in less than a week, but because I am studying full time I could only work on it in the evenings. I have built excavators and dump trucks using similar techniques in as little as three days,” said Vannarith.

He used a drive belt and gears to operate the harvester, while straps and skewers were used to collect the rice. The cutting blades were made from cardboard and narrow pipe.

The public was surprised by his unique abilities, and even more impressed when they discovered that he had had no formal training.

“I just learned how to do it by myself. I look at the real machinery, and then I start by producing several models. Finally, when I think the model will work, I install the engine and electronics,” he told The Post.

However, he admitted that the production of the first prototype was difficult, and it took three attempts before he was ready to fit the dynamo and remote control pieces.

Vannarith said he did not receive training from anyone on the installation of the engine, although his electrician father told him “try more than you fail and you will be successful.”

Among the six models he built, he was only able to install an engine in one, due to a lack of finances.

Education department director Bunroeung was very interested in all of the items on display, and also expressed an interest in adding a rocket building contest into next year’s fair.

“This year we just organised a regular fair, with no prizes awarded – next year we will make it a competition,” he said.

Buth Sa Art, Vannarith’s 45-year-old mother, said she was overwhelmed by the public’s interest in her sons work.

“Next year there will be a competition, and I will be encouraging him to join,” she said.

In preparation for next year, Vannarith is planning to produce new machines that cost little money but provide large benefits.

“For next year’s competition, I will make a soil crushing machine and a water pump. I estimate that I will probably have to spend around 90,000 riel for these two machines, but I want to use some new parts, as sometimes it is easier than adapting old parts,” he said.

He also demonstrated his ambition, saying that he would like to compete in Phnom Penh in the future.

Regarding the study of STEM education in industry 4.0, his mother said that she cannot afford to send her son to study in Phnom Penh, and requested that schools or other institutions offer her passionate talented son access to scholarships.

“I would like to ask schools or donors to help my son to obtain a scholarship. He really wants to go Phnom Penh to study these skills because of his passion – and he’s talented,” she said.

“I very much want to study STEM skills. Unfortunately, I do not have the money to study these things, and in Serey Sophorn there is no in-depth teaching of them. I want to study in Phnom Penh because in the future I want to be a tech device designer,” added Vannarith.


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