Mr Mitra started with the simple concept in 1999. He used computers from NIIT, a computer learning centre where he used to work, and put them up with Internet connections on the walls of a slum in Delhi. He observed children as they tired their hands on these machines, and learn using the Internet and get basic knowledge of various subjects like science and mathematics.
Mr Mitra recorded these self-learning classes with the help of a hidden camera. In a few years, his idea transformed the lives of many slum children.
"When I first came here, there was no keypad, no mouse. I thought this was a video game. Then I realised this has a lot of knowledge too. Gradually, I got a hang of it. Then when computers came to my school, people realised I already knew about them. It made me very proud," says 18-year-old Rubina, who lives in Delhi's Madangir slum. Her mother works as a maid in the area; her father died many years ago.
"When these computers were installed here, she was 12, and her mother wanted to get her married. Now she is above 18 and is pursuing a bachelors' degree and is not married," says Ritu Dangwal, a senior consultant at the 'Hole in the Wall' systems.
After Delhi, where there are about 100 such self-learning points now, Mr Mitra and his team set up such computer systems in Madhya Pradesh, Uttar Pradesh, Maharashtra, and even in a few countries across the world.
Mr Mitra says he was amazed by the response to his little experiment. "A boy from Maharashtra spoke about a magazine he read on a 'Hole in the Wall' computer. It's called 'New Scientist'. It's something read by scientists. I met him last year again. He's got a Yale PhD now. And I said to myself, 'Oh my God! This boy has made it'," he recalls.
But Mr Mitra is not resting yet. The scientist now wants to make a 'School in the Could' , an experiment that will use the Internet and mediums of online conversation like Skype to build online learning centres to help underprivileged children get information, and use it online.
From our side, it's best of luck to Dr Mitra.