His experiments have yielded unexpected dividends - soon, under the label Freetronics, several products built using the Arduino as a base, will start appearing on the shelves of Jaycar Electronics, a popular store in Australia.
Interest in open hardware has also grown to the point where it is beginning to look likely that an open hardware conference may take place in Melbourne this year.
Oxer told iTWire that five resellers in Australia, two in New Zealand and one in Germany would sell the products, things like an ethernet shield and ethernet midspan injector.
The Arduino is a cheap, tiny computer system that was originally designed as a teaching tool and building block for people who want to add some intelligence to objects such as kinetic sculptures and other gadgets.
"That's (the Jaycar deal) obviously a huge deal for us as a business, but it's also very significant to the open hardware community in general because it means that, possibly for the very first time, a major Australian retailer will be selling hardware licensed under the TAPR Open Hardware Licence," Oxer (left) said.
"It's a major validation of the whole concept of open hardware, just like in the early days of Linux it was significant when major companies like IBM started supporting open source commercially."
The development of products came about as a spinoff after Oxer wrote a book called Practical Arduino. "When working on the book, my expectation was that I was going to provide parts of this information so people could go off and build their own projects," he said.
"But what happened was that a lot of people contacted us afterwards and wanted to buy kits and other things related to the book. So I started investigating how hard it would be to put together some hardware.
"This is where one of the interesting differences between open hardware and open software come in - with open software it's quite easy to publish the source code and the whole tool chain, like compilers or whatever else is necessary. You can give everybody, at zero cost essentially, everything they need to reproduce your work and to develop and build on it.
"With open hardware it's quite different. I can give someone the design parts for a project but then they need the actual materials or the tools and resources to reproduce it in order to improve on it or collaborate with me." (Below: the ethernet shield with PoE)
The cost is relatively small but there is some specialist knowledge involved. "There are certain things that you can go and buy off the shelf but there are some things which are purpose-built for a project. There will be a circuit board which will have a custom design just for that project and then other parts that you can then buy off the shelf. Buying the shelf parts is not a problem. Things like printed circuit board manufacturing is a problem."
When Oxer wanted to put together some kits for his book, he started looking into what would be involved. "I talked to some people who have done PCB manufacturing before and they gave me some advice, told me whom to talk to and helped me out designing a few circuit boards and came up with some designs.
"We sent them off to a fabrication company to have them manufactured. One of the things about circuit boards is that - with electronics in general - economies of scale kick in very fast. Doing one of something and doing 10 of something costs about the same.
"Hence, rather than doing one or two circuit boards yourself, you might as well do a hundred. The actual incremental cost is very small. I ended up having circuit boards manufactured in reasonable numbers, like in the hundreds. I started making them available online for people who wanted to buy them and it all went from there. It turned out to be very popular and a lot of people have been buying them."
Oxer says lots of little things can be built with the Arduino, depending on one's imagination. "One of the devices that we've worked on recently is an equivalent to an Arduino; it's the main micro-controller board that you would use as a general purpose board for lots of different projects.
"Just recently I heard that it's been used in vending machines in New Zealand. At the moment we're using it in rocket avionics systems. People build them into remote control cars or home automation systems."
He does not intend to focus on retail sales. "What I'm interested in is providing a mechanism for people who have ideas for designs to be able to have them produced in a professional way. I didn't want to end up creating a business where I would have shelves of commodity parts that you can also buy down the street.
"We're really only selling the things that we design or the things that we manufacture on behalf of other people. They're all open designs - all the designs are published under an open hardware licence or a creative commons licence."
One of the little boards he has produced is called MobSenDat - a mobile sensor data logger. "That's a little micro-controller board, about seven centimetres by about five centimetres; it has some memory on it, a flash memory card, so it can record data. It also has an accelerometer, a barometric pressure sensor, temperature sensor, GPS and a couple of radio transmitter options. It can be put into something like a high-altitude balloon project."
One of these boards was recently flown to an altitude of 30 kilometres by the Adelaide-based Project Horus. It recorded all the flight details, like the temperature and air pressure for example.
One of Oxer's recent designs is an RFID door lock shield which is an expansion board for an Arduino. "It allows you to connect an RFID reader, typically used on buildings for access control, and it has an output to control an electric striker plate," Oxer says.
"It can control the door lock. This is what I use on the front door of my house. When I walk up to the front door I put an RFID tag near the door and the door unlocks."
He has also built a security sensor shield. "What that does is it lays an interface of typical security sensors like motion detectors into an Arduino. You can then use them in either a security system-type application or more generally you might use motion detectors in something like an art installation." (Below: the 16x2 LCD shield)
Fiddling around with the Arduino is not limited to the hardcore techie. "One of the interesting things about the Arduino is that it has a very low barrier to entry technically, which means that it's not limited to just engineering types or computer science people," says Oxer.
"A lot of people who use it are artists or people who have other interests. They might have an idea and not really know how to implement it, how to put it into practice.
"The Arduino is a really simple building block that they can then use to bring their idea to life. What we're seeing is people like artists using something like a motion detector from the security system to detect when someone walks up to an installation, and have the installation start moving or reacting in some way. That sort of thing is quite easy to achieve because a lot of the building blocks are there already. It's a matter of taking those building blocks and plugging them together in a different way, and setting up some sort of behaviour."
Oxer ran a mini-conference on the Arduino at the 2010 Australian national Linux conference; this year, he ran a practical Arduino mini-conference.
"One of the big growth areas in the last couple of years has been hackerspaces," he says. "A hackerspace is a shared environment which could be as simple as someone's garage, like the hackerspace in Melbourne.
"There are a number of tools and there are times scheduled for people to come together and collaborate on projects, to talk about what they're working on and get help from each other, or use tools they don't necessarily possess themselves. It's a way of getting people started.
"It provides mentoring and access to facilities they wouldn't otherwise have. In the last couple of years, hackerspaces have grown up around Australia and around the world.
"A lot of people participating in hackerspaces don't necessarily come from a technical background but it gives them an opportunity to get into this sort of thing. A lot of the training is not really formal, like sitting down in a class or a tutorial.
"It's coming along to these informal events and then learning from people who have already been through the process. One of the other things, though, is that there has been so much interest in open hardware at the recent Linux conference (in Brisbane) and various other things that just over the last couple of days there has been talk about running an open hardware conference." (Below: the 4-Channel Power-over-Ethernet Midspan Injector)