Pranay Devnani MSIE 2016

Emily Scott

A recent ISE graduate research project could potentially change the way cell phones are refurbished.

Pranay Devnani, a 2016 graduate of the Industrial Engineering master’s program, published his research on using existing sensors in cell phones to determine quality at the end of the life cycle. The paper won best track paper in Sustainable Development at the 2016 Industrial and Systems Engineering Research Conference.

Devnani got the idea after thinking about how an accelerometer, an instrument present in cell phones, can tell you how many times a phone has been dropped.

“I kept thinking about other sensors that already exist in a phone, and how they can be used to predict the quality of a phone,” he says.

So he spoke to his advisor, Professor Deborah Thurston, and they decided to explore the idea through further research. For the next few months, Devnani and Thurston worked on figuring out how phone manufacturers could use these pre-existing sensors in smartphones to estimate their value.

“Today, if you want to sell your cell phone, you have to go on Best Buy or Amazon and mention which model it is, you tell them the condition of the phone, and based on that they give you a price,” Devnani says.

This approximation process leaves room for error, which could lead people with low-quality phones to be overpaid, and those with high-quality phones to be underpaid.

Devnani wanted to see if there was a better way to estimate the quality of the phone before it is sent in for refurbishment. He examined the four sensors already present in most smartphones: a battery sensor, a thermometer, a humidity indicator, and an accelerometer, which in this case measures how many times a phone has been dropped.

“What I’m doing is repurposing the same sensors and the same data to predict the value and quality of a phone once the life cycle is over,” Devnani says.

This method could provide more accuracy, lower the cost of inspecting refurbished phones, and reduce e-waste, a growing environmental problem.

“What this research aims to do is try to reduce the environmental impact any manufacturing company makes,” Devnani says. “This also will increase the profitability of a company by making a product once and selling it twice.”

Additionally, this method could help manufacturers hand pick the best quality phones for a second life, as opposed to randomly testing and selecting phones that are sent back.

But the method Devnani proposes could expand past cell phones and apply to any device with a sensor, such as washing machines, cars, and medical devices.

In the future, Devnani says it would be more accurate to create new, better-designed sensors, rather than repurposing existing sensors, to help predict the value of a device.

“My contribution to this is introducing a new method of solving an age-old problem,” he says. “The next step would be to collect this data, collect sensor data for its entire life cycle, and try to convert it into actual data points. Using these data points, you can actually predict what the value of the quality of the phone is.”

After graduation, Devnani was hired at Apple as a product quality engineer for the iPhone team.

“It’s pretty good to join such a big company in a good position,” he says. “I think it’s a good start to my career.”

Pranay Devnani presenting his research at the Graduate Poster Symposium.
Pranay Devnani presenting his research at the Graduate Poster Symposium.



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All ISE undergraduate and graduate students are invited to submit a graphic, visualization, or photograph of one of their own current or recent engineering projects, to win a cash prize and official, wide-spread recognition.


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