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# Technology whose time has come

16 Jan 2014
Taken from the January 2014 issue of Physics World

Joshua Pearce describes how physicists can help bring simple, affordable and life-changing devices to people and laboratories all over the world, using the concept of open-source appropriate technology

Several years ago, I was teaching introductory physics lab courses at a small university. As is common at many universities, much of the equipment there was outdated, and the experiments – one of which actually included watching ice melt – left a lot to be desired in terms of igniting my students’ enthusiasm for the wonders of physics.

At the same time, as part of my own research on solar energy, I had just begun taking a serious look at the concept of appropriate technology (AT). This term comes from the world of economic development, and it refers to technology that can be easily and economically constructed using materials and techniques that are readily available to local crafts-people. In academic studies and early work by the World Health Organization (WHO), AT has been shown to play a central role in the alleviation of poverty in the developing world. Yet research and development on these technologies generally receives only modest support from institutions in richer countries. One reason for this lack of support is that the operation of many AT devices depends on relatively well-understood science. In fact, it depends on the sort of science that is accessible to pretty much anybody – including my introductory physics students.

### Fully formed

One particularly interesting recent area of OSAT development is “distributed additive manufacturing”, which uses 3D printing to make everything from solar-distillation devices to hand-cranked generators. Broadly speaking, 3D printers work by taking in a filament of the working material (a popular one is a plastic called ABS, which is used in making LEGO bricks), heating it and then extruding it through a nozzle to produce a single 2D layer. By raising the printer’s vertical axis and repeating the process many times, it is possible to construct a 3D object layer by layer (see September 2013 pp25–29).

Although some commercial 3D printers cost thousands of pounds, there is an open-source 3D printer known as a RepRap – the name is short for “self-replicating rapid prototyper” – that can be built for less than £400 and is capable of printing around 50% of its own components. RepRaps use computer-aided designs that can be shared over the Internet as easily as photographs. Hundreds of RepRap-friendly designs for OSAT devices exist already, including “recyclebots” that turn waste plastic into 3D printer filament. It is also worth noting that components of many scientific instruments can be made using RepRaps – a fact that could reshape the landscape of science education and research in developed countries as well as developing ones (see “Open-source 3D-printed scientific equipment”).

There is plenty of research left to do in this area, including improving local availability of feedstock for polymers and other materials (including ceramics and metal); increasing the maximum size of printed parts; improving the material properties of the printed objects; and using renewable-energy systems to power the production. My collaborators and I have already started working on solar-powered 3D printers that fit in a suitcase. However, more work is still needed to extend existing 3D printing technology before a complete, village-level OSAT fabrication process will become a reality.

### Getting involved

Physicists have a good track record of opening up science for the common good. We have been sharing our open-access e-prints on arXiv for more than 20 years, long before “open access” became a buzz-word. Given this background, I think it is time for physicists to take a serious look at OSAT.

If you are already doing research that could directly contribute to sustainable development, I suggest you start sharing your work on Appropedia. This advertising-free website works like Wikipedia – anyone is allowed to create and modify content directly from their Web browser – and it has become the primary site for collaborative solutions in sustainability, poverty reduction and international development. On it, you will find project examples, descriptions of best practice, “how tos”, ideas, designs, observations, experimental data, deployment logs and much more. Most of the projects on there have been created by development workers and students, and many of them would benefit from the analytical minds of physicists. In addition, Appropedia would welcome summaries of your latest results on technical topics related to the site’s mission. And of course, if you need field partners to help test some of your ideas, there are some perfect collaboration opportunities just waiting to happen.

By sharing equipment designs with the open-source community, you will help other groups lower their laboratory costs and make your equipment accessible to researchers in the developing world. Moreover, you will also benefit directly when members of the international open-source community hack your equipment to improve it and then share the new, enhanced design with everyone. With OSAT, we all win.

### Open-source 3D-printed scientific equipment

A number of designs for scientific equipment are available online. For example, some of my work on solar water purification requires heat exchangers, which needed very expensive prototyping with laser welding. We were able to build a digitally controlled laser welding system, using printed parts and open-source plans, for less than the price of a single heat-exchanger prototype. We also used a script in OpenSCAD to make a chemical oxygen demand analyser (see “Printable lab equipment”). This analyser runs on a simple version of an open-source Arduino Uno microcontroller and all the black components were synthesized using a RepRap 3D printer. We have shown that it is as accurate as commercial models but costs two orders of magnitude less.

If your research takes place on the nanoscale, you might be interested to hear that the University of Münster in Germany has developed an open-source scanning tunnelling microscope for a fraction of the cost of commercial systems. If your work requires optics, you might consider using a RepRap to print components from the open-source optics library. This library contains free designs to build a research-grade Michelson interferometer or a hand-held spectrometer, along with many other tools. And physics teachers, take note: a basic optics lab set-up for an entire class costs only about £300 to print, compared with a retail cost of about £9000. I have documented dozens of other examples in my book The Open-Source Lab: How to Build Your Own Hardware and Reduce Research Costs (2014 Elsevier).