The Relexer phone and the wrist that reports to the doctor

What it was

In November 2009, design blogs picked up a phone concept called Relexer by Chinese designer Lu Yin. It was aimed at city workers with packed schedules: a phone that also kept an eye on the body.

The published renders show two parts. One is a white, pen-shaped body with a screen that pulls out sideways like a scroll. The other is a thin flexible band, described as a thermometer worn around the wrist like a bracelet, with a color scale that runs from blue through green to red. The phone was meant to notice when readings drifted and to send a daily or weekly summary to a doctor.

That is about all anyone knew. When Concept Phones covered the Relexer in July 2010, it said it had no further details and could only suppose that the screen was a flexible display. We found no sensor specification, working model or manufacturer.

The Relexer put the thermometer on the wrist and the doctor on the line, and the industry kept both and dropped the special phone.

Where the idea went

The Relexer itself went nowhere. In 2019 the finance site Lovemoney included it in a gallery of clever ideas that failed, and added that smartwatches had since taken on much of what it promised.

That is a fair summary. In September 2014 Apple announced the Apple Watch with a built-in heart rate sensor. In September 2018 the Series 4 added an electrical heart sensor and an ECG app, which received a De Novo classification from the US Food and Drug Administration.

The other two promises took longer. In June 2021 Apple said iOS 15 would let users in the United States share Health app data, such as heart rate and hours of sleep, with doctors at participating healthcare organizations. In September 2022 the Apple Watch Series 8 added two temperature sensors that sample the wrist every five seconds during sleep and register changes as small as 0.1 °C.

What it means now

Lu Yin got the location right. The wrist turned out to be the place where a device can read the body all day without asking for attention. The concept also saw that a reading matters most when it travels: a trend a doctor can look at is worth more than a number on a screen.

It was wrong about the object. The phone did not need to become a medical instrument. The sensing moved into a watch or a band, and the phone became the place where the numbers are stored and shared.

The makers are also more careful than the concept was. Apple states that its temperature feature is not a medical device and is not intended for diagnosis. That is a more modest claim than a phone that spots an illness before it starts.