TOOLBOX AGE OF THE ARDUINO A booming market for small, cheap ‘single-board computers’ offers researchers a helping hand in fields such as automation, networking and data collection. ILLUSTRATION BY THE PROJECT TWINS THE PROJECT BY ILLUSTRATION BY DANIEL CRESSEY configurable computing devices that have taken to (and transmit data from) remote field transformed the field of homebrew and do-it- locations. All it takes is a little ingenuity. research subject watches a brush slowly yourself electronics. Increasingly, they are stroking a rubber hand on a table in transforming the research community too NO EXPERIENCE NECESSARY front of her, while her own hand — (see ‘March of the mini-computers’). Avail- Although researchers have been custom- Ahidden from view — experiences the same able for as little as £4 (US$5) for the basic izing computers and integrating them into stimulation. Eventually, the subject starts to circuit board, or about £50 for a kit including their experiments for decades, the market think that rubber hand is her own. power supply, case and cables, these systems for small, cheap, ‘single-board computers’ This rubber-hand illusion is a trick of the have little in the way of bells and whistles, and has boomed in recent years. The Raspberry mind. But it is also a trick of design. Normally, the learning curve can be steep. Yet Arduinos Pi — a fully fledged computer that can run the illusion is created by people who have care- and similar devices, such as the Raspberry Pi, the Linux operating system — appeared in fully practised using brushes to stroke the real pack considerable power on their diminutive 2012; by September 2016, 10 million had been and rubber hands simultaneously. But Isa Rao, boards, providing tremendous opportuni- sold. Arduinos — technically, programma- a psychology PhD student at the University of ties for automation, networking and data ble microcontrollers rather than computers Glasgow, UK, who uses this set-up to gain collection and analysis. — have been similarly popular since their insight into how people relate to their own For researchers, those features can translate launch in 2005. Off-the-shelf accessories for bodies, has built an automated rig that deliv- into benefits both economic and practical. these devices include cameras, motion sensors, ers the stimuli without a trained assistant. At its Users can shoehorn the systems into tiny thermometers and Bluetooth adaptors. There’s heart is an Arduino microcontroller. spaces, deploy them without monitors or even an all-in-one system developed for an Arduinos are one of a growing num- keyboards, buy them in bulk, and pack them outreach project on the International Space ber of low-cost, stripped-down, and highly into autonomous devices that need to be Station; the system combines a gyroscope, ©2017 Mac millan Publishers Li mited, part of Spri nger Nature. All ri ghts r6es eAPRILrved. 2017 | VOL 544 | NATURE | 125 TOOLBOX an accelerometer, a magnetometer and can transmit its data to another computer for sensors to measure temperature, barometric MARCH OF THE MINI-COMPUTERS analysis, for example, or that integrates with pressure and humidity. The number of papers including the terms a camera or external sensor for more com- ‘Raspberry Pi’ or ‘Arduino’ has been rising in Here on Earth, Raspberry Pis, Arduinos and databases of scientic publications. plicated studies. In De Souza’s bee study, the similar devices have been used to build under- bees were fitted with tiny radio-frequency- 400 water sound recorders for marine research, identification chips that trigger a scanner as Scopus robots for assembling gene-editing tools and PubMed the animals pass by. The Edison computer, systems that can rapidly identify drug-resistant 300 located inside the hive, processes the resulting SOURCE: SCOPUS AND PUBMED pathogens from human samples. data and uploads them for analysis. Hakho Lee, who researches medical “Consider the options available and diagnostic systems at Harvard University 200 perhaps review the requirements to see what in Cambridge, Massachusetts, and who has you might be able get away without,” says developed a system to diagnose antibiotic- De Souza. And be prepared to update your resistant bacterial infections, says he initially Number of articles 100 equipment as systems evolve. For his bee- tried to build that system using smartphones monitoring project, for instance, De Souza as the central computers, but the phones were 0 has migrated from another single-board com- hard to break apart and reconfigure. By con- 2010 2012 2014 2016 puter, made by a company called Ledato, to trast, systems such as the Arduino and the Pi a Raspberry Pi; from there to a Galileo; and cry out for customization, making them ideal finally to an Edison. for integration into scientific sensors. recordings, in an easy-to-use package, makes “The Arduino system in this case is perfect,” [the Arduino] an attractive option,” he says. FOLLOW THE BEATEN PATH he says. “They already have so many different For those starting out, there are advantages to flavours and they’re modular. Which means MONEY DOWN sticking to the most popular devices — namely if I want to add Bluetooth, all I have to do is Before researchers can start building, they the Raspberry Pi and Arduinos. purchase that module and plug that into the must decide what to buy — in what has User forums for both systems are extremely motherboard.” become a bewilderingly crowded marketplace. popular, with millions of posts and hundreds Although Lee has a long history with Three generations of the standard Raspberry of thousands of members, providing a useful gadgetry and electronics, such a background Pi are now available, plus a basic $5 ‘Pi Zero’ resource for novices. Researchers have turned isn’t necessary; the plug-and-play nature of version and a low-power version. Arduinos to these forums for assistance with anything the devices has attracted researchers with no come in even more flavours. Then there are from using Arduinos to accurately calculate previous experience in electronics or program- the Galileo and Edison boards from Intel, the the girth of trees, to setting up temperature ming. Turning the Raspberry Pi board into a open-source Banana Pi, the Odroid (based on sensors. The foundation behind Raspberry Pi functioning computer is as simple as slotting the Android operating system) and more. even has a series of videos and a list of common in an SD card preloaded with a Pi operating Choosing a device involves thinking mistakes on its website, to help newcomers get system, and plugging in a monitor, keyboard, carefully about three variables, says up and running. mouse and power supply. Programming the Paulo De Souza, who works on microsens- “What you really don’t want to do is be fixing device takes a bit more work, but detailed ing technology and systems at Australia’s technical problems that people have already descriptions online should provide more than Commonwealth Scientific and Industrial solved,” says David White, a computer scientist enough help for most people. Research Organisation, a governmental at University College London who has worked Indeed, the Raspberry Pi was originally research agency based in Canberra. These extensively with Raspberry Pis. “It would save designed to teach variables are cost, capability and size, he says. you a lot of time if you go with standard solu- children in British “You can just “Generally, you need to pick two of the three; tions. You can just harness the popularity of schools about pro- harness the it is difficult to get low cost, small size and high these devices — there’s so much out there.” gramming. Pis and popularity of levels of capability in a single device.” Assistance does not have to come from the Arduinos speak lan- these devices — For example, De Souza has worked on Internet, however. “Sit down with someone guages based on C++, there’s so much autonomous machines, including submarines else who has worked with these before- so a background in out there.” and rovers, that need to be power-efficient and hand,” says White. Or, says De Souza, bring that programming able to process complex sensor data. His team in postgraduate students with backgrounds language is useful, but not essential to getting picked the Odroid XU3 (now superseded by in information technology. “IT students are started, says Takeo Katsuki, a researcher at the $60 XU4), which is more expensive than a passionate about their area and are always up- the Kavli Institute for Brain and Mind, part of Pi, but much more powerful. But for a project to-date with the latest solutions,” he says. the University of California, San Diego. “Pick studying bees, he used an Intel Edison, which Some researchers eventually find that a project and start tinkering with it.” (One has lower power requirements and can even their experiments demand too much of Pi or possibility is a variant on the ‘Hello, world!’ run on solar energy. Arduino components. Katsuki switched to the exercise familiar to programmers. Usually, the Scientists also need to consider how their myRIO controller from National Instruments goal is to display that message on the screen; computer will talk to other elements in their when he found that the software clock in his here, the idea is to direct the board’s built-in experiment. Raspberry Pis connect to stand- Arduinos was not accurate enough for the LED to blink on and off.) ard monitors, USB keyboards and mice. But Flyception system. Lee plans to upgrade to Katsuki placed an Arduino at the heart of a as microprocessors, Arduinos must be linked another device — the Jetson, from California- system he developed called Flyception, which to a computer using cables so that they can be based firm NVIDIA — to gain greater process- allows researchers to monitor brain activity in programmed.