Wayne Lewis has recruited someone who he reckons is the best tester in the world for his iPad app - his seven year old son Ciaran.
"He has found a lot of my bugs, actually," says Lewis, who developed the Communicate Easy iPad app for children with autism and special learning needs.
Ciaran is one such child. He is non-verbal and needs help to complete daily tasks like getting dressed.
Lewis, a senior software developer at Datacom, says the idea for the app "just came naturally".
"I needed to do it," he says.
"I am very much focused on my son."
Lewis started working on the app nearly two years ago when he read how the iPad can be used as a tool to help children like Ciaran.
"When the iPad first came out I thought it was just an oversized iPod or something like that," says Lewis.
He saw it differently after reading the article and checking out the features of the iPad. "I got excited."
Lewis looked at some of the apps that were already available for children with autism. He says that while some of these were good, there were times Ciaran struggled to use them.
"I will just try to knock out something," he says.
"It became a baby, really," he says, smiling, as he estimates it took nine months to develop the app and prepare it for downloading at the iTunes store ($2.59).
It took this long because he was developing the app in the evenings, after the kids were in bed. He was starting at 9.30pm and some nights not finishing until 2am.
While his son played a key role in defining the features of the app, colleagues also provided input. A Datacom workmate gave him some advice on the design, while another colleague at Tower Insurance, where he was assigned for a Datacom project, helped him with search engine optimisation.
The first version appeared in July 2012, and was initially available in several countries including the United States, Australia, the United Kingdom and New Zealand.
Today, he estimates there have been around 750 downloads, half of which come from users in the United States. The second highest number of downloads is from New Zealand.
Lewis is giving a percentage of the sales revenue to Autism New Zealand (100 per cent of local sales, and 10 per cent from global sales). The proceeds from the app will also help pay for Ciaran's therapy.
Alison Molloy, Autism New Zealand chief executive, says Lewis had approached the organisation after he and his wife attended a programme for parents of children with autism who are under five years old.
"Wayne's product was one of the better ones that we have seen," says Molloy.
"Technology is something that is becoming much more of a reality for everybody and enabling children to both communicate in a way that does not make them anxious is very important."
Lewis says developing the app was "very different from his day job" where he works with Microsoft technology.
"App development is a tricky thing to get into and if you are looking to do an app you really have to do your homework," he says.
"Make sure you got something unique and that you do the right marketing to get yourself in these sites and that you are visible out there."
On the development side, he says, "I learned about iOS and the iPad itself. It is not different from my everyday job in that respect in that the more you do it, the more you find out about it."
Market research is important, says Lewis.
"Spend a lot of time thinking about what is out there, how you are going to improve it and think of innovation. Think of things maybe nobody else has thought of."
When he started work on the app, there were only a few similar apps available, but by the time it was released, there was more competition.
Lewis says he had to do a lot of research on trademark laws, and was careful in choosing the name of the company just in case it has already been trademarked.
He decided to combine the names of his cats Pluto and Jasper to come out with Pluja Apps Limited. He then learned the word also means 'rain' in Catalan.
"Once I got the app out there things were very slow in taking off," he says.
"I thought I spent all this time developing this app and no one is getting the benefit of it. I just want people to use it but I don't want it to be free because a lot of hard work has been put into it."
He says his IT background has helped him make the app more intuitive and user friendly and he has followed standard app behaviours to help ensure the finished product was robust and less error prone.
"A lot of thought was put into the initial design and how it may be extended in the future," he says.
"Therefore the app is extensible; making future changes is easier - without needing to redesign parts of the app."
The ultimate test was his son's reaction. "He responded very quickly," says Lewis.
"I filled it up with things he likes - his DVD, his books, and some out and about things he likes to do."
Lewis continues to work on the app and the next release will include a lockdown option for functions.
This came about when they were using the app to complete the six functions for toilet training. Ciaran "was just having a field day," hitting the back button, which meant he could not tick each step for the task as he completed them.
This new feature means he will not be able to leave the page until the schedule is completed.
"He is forced to do the whole thing. It is something that came out of necessity from my own situation but I think it will be very useful... that is one of the advantages of a developer of an app having an autistic child."