The former CSIRO scientist sparked a global movement, capturing the imagination of people all around the world in her quest to take old dolls and make them something not only new but accessible for kids.
"I am surprised that so many people thought that I set out to make a statement, because I'm not really a political person," she says.
"But what I've done has brought forward the opinions of a lot of parents and children and what they want to see in toys."
The story became a viral hit, being viewed over 45 million times and seeing Singh interviewed by media outlets in the US.
"A lot of them are second-hand Bratz dolls," says Singh.
"What Tree Change Dolls is all about is giving some old toys a more down-to-earth, natural looking style.
"I've just been overwhelmed with the responses from people. I did not expect them to go viral.
"Most of my life I've tried to remain quite anonymous ... it's just a little bit crazy.
"I'm surprised that I've done something which has managed to appeal to so many different people in so many different ways.
"What I really love to see is people haven't been just inspired by me, but they've come up with their own take on it which I think is really, really wonderful to see my idea not just grow but branch out into different areas."
One of those people is Wiradjuri woman and mother Lorna Munro.
In the Sydney suburb of Redfern, more than 1600kms away from Sonia's home in Hobart, she is making her own re-styled dolls - Koori Doll Creations.
"I've lived in the Redfern community my whole life and I paint dolls, I play with dolls," she laughs.
"When I saw the video I thought I'd just give it a go and try to make them like the beautiful, black woman that I know.
"Culturally appropriate dolls made by Aboriginal people just aren't out there.
"It really just sort of dawned on me how important it is for children to see themselves in these dolls."
Munro has been working on her dolls from home, using possum and kangaroo fur to give them authentic clothing and details of her ancestors.
"What I would like to see is just that little black girls and boys come to the realisation that they are special and that they are beautiful," she says.
Munro and Singh had an opportunity to meet in person and bond over their shared love of both dolls and making them for all people, of all races and ages.
"It's great for people to realise that you can take some action yourself and you can change things," says Singh.
"What Lorna's doing is really important because I've received lots of emails (from people) saying that they loved their dolls as a child, but they never felt any of dolls looked like them and how that affected that self-esteem.
"I can see that things are changing a little bit.
"I think a lot of people find it surprising that this has turned into such a big thing, I mean, they're just dolls.
"But from all the response I get they just touch peoples hearts. I guess in the end they're not just dolls, they're something really important."