- Cell Phone Spectrometers Bring Tech to Classrooms
- A scientist has developed a low-cost, cell-phone-based spectrometer—a basic device used in chemistry and other sciences. He hopes that the tool will bring critical thinking to classrooms and inspire other developers.Some high schools might soon need to rethink their policies against cell phone use in the classroom. A researcher at the University of Illinois has developed a low-cost, easy-to-use analytical chemistry instrument that uses students’ cell phones to bring technology to the classroom.
The spectrometer is one of the most important basic chemistry instruments. The tool shines white light through a sample solution and allows scientists to determine chemical makeup depending on how much light is absorbed. The machine is used in most physical and biological sciences for identifying and quantifying substances.
A standard spectrometer can cost several hundred dollars, while a high-end machine can cost thousands. Naturally, most high schools lack the budget to stock many of these machines. Even when the device is available, it fails to teach students the underlying properties of chemistry, since they’re likely to just use the machine and copy down numbers.
Made of simple, low-cost components, the cell phone spectrometer costs under $3 (source: L. Brian Stauffer).
A chemistry professor at the University of Illinois, Alexander Scheeline, has frequently dealt with these problems. “Science is basically about using your senses to see things,” he said in a statement. “It’s just that we’ve got so much technology that now it’s all hidden.”
“The student gets the impression that a measurement is something that goes on inside a box and it’s completely inaccessible, not understandable—the purview of expert engineers,” he said. “That’s not what you want them to learn. In order to get across the idea, ‘I can do it, and I can see it, and I can understand it,’ they’ve go to build the instrument themselves.”
Setting out to address these issues with spectrometers, Scheeline has designed a low-cost, simple, and open-interface machine. Although he realized that such a spectrometer might not be particularly sensitive or accurate, he saw these shortcomings as educational opportunities.
“If you’re trying to teach someone an instrument’s limitations, it’s a lot easier to teach them when they’re blatant than when they’re subtle. Everything goes wrong out in the open,” he said.
Scheeline’s spectrometer has remarkably simple and inexpensive components: just one light-emitting diode (LED) powered by a 3-volt battery—the type used to remotely unlock a car. Diffraction gratings and cuvettes, which hold sample solutions, cost just a few cents each and are readily available from scientific supply companies. Together, all of the parts cost less than three dollars. But Scheeline’s spectrometer still needed one crucial element: a photodetector, which could capture a spectrum for analysis.
“All of a sudden, this light bulb went off in my head: a photodetector that everybody already has! Almost everybody has a cell phone, and almost all phones have a camera,” Scheeline said. “I realized, if you can get the picture into the computer, it’s only software that keeps you from building a cheap spectrophotometer.”
Alexander Scheeline hopes his device will inspire other developers to bring low-cost technology to the classroom (source: L. Brian Stauffer).
Scheeline wrote a computer program that analyzes spectra captured in JPEG photo files and posted it for free downloads online. He even uploaded instructions for how to build and use the cell phone spectrometer.
Scheeline has successfully tested out his device in high school science programs in Atlanta and with students in Hanoi, Vietnam.
“The potential is here to make analytical chemistry a subject for the masses rather than something that is only done by specialists,” Scheeline said. “There’s no doubt that getting the cost of equipment down to the point where more people can afford them in the education system is a boon for everybody.”
Scheeline recently wrote about the potential of his device in the journal Applied Spectroscopy. He hopes that his device will inspire other scientists to develop low-cost, cell phone-based tools for classrooms.