Low-cost vital signs monitoring system could transform smartphones

Low-cost vital signs monitoring system could transform smartphones

Technology News |
By Rich Pell

The company is pursuing medical regulatory approval for its technology in the United States and Europe and 12 other territories that together cover 97 percent of the available smartphone market. The five vital signs are temperature, pulse and respiration rates, blood oxygen levels and blood pressure and give rise to the name of the module – V sensor. The LMD technology will enable users to check their health in 60 seconds, the company said.

Mark-Eric Jones, CEO of Leman Micro Devices

Importantly for LMD’s business model of selling approved medical modules to go inside smartphones, LMD has obtained agreement from medical regulators — including the US Food and Drugs Administration (FDA) — to treat the smartphone into which LMD’s technology is fitted as an “accessory” to the medical device.

This means that smartphone makers will not have to seek their own medical approval. Mark-Eric Jones, co-founder and CEO of Leman Micro Devices (LMD), told eeNews Europe that he expects approvals from these authorities within months and to have design wins for the V sensor module in smartphones in the second half of 2017.

Jones said that the module would cost less than $5 initially but in time it would reduce to less than $1 and effectively all smartphones could be equipped with a vital-signs monitor system, just as today they come with a dual camera.

Next: How the measurements are made

The blood pressure measurements are made using the same scientific principles as the cuff used by professional medical equipment and like the cuff does not require calibration, according to LMD.

Leman envisions that the sensor module will be incorporated in the edge of a mobile phone and the user presses their index finger. An application on the smartphone with an in-built game helps the user to vary the pressure and data on the pulse is obtained using an infrared LED and photodetector.

A conventional temperature-calibrated MEMS sensor is used to measure pressure and IR photoplethysmography (PPG) can then detect the variations in the systolic and diastolic pulse at different pressures just as the cuff does using the Riva-Rocci arterial occlusion method.

CAD rendition of V sensor module. Source: LMD

The module, which measures 15mm by 5mm by 4mm is based on bare die and also includes an infrared thermopile for non-contact measurement of temperature and uses the IR PPG to measure heart and respiration rates. A red LED is used alongside the IR LED to measure blood oxygen levels.

The module also contains a custom ASIC, designed by LMD and manufactured by TSMC in 180nm CMOS, to condition the signals coming from the various sensors and to send the data out to the application processor which hosts the vital signs app, which is known as Elemdy.

Module prototype show next to millimeter-divided scale. Source: LMD.
Block diagram of V sensor module shows multiple sensors, emitters and ASIC. Source: LMD

LMD’s first key patents have already been granted in several territories and it has an IP pipeline of six families of patents.

“Hypertension is one of the world’s most neglected killers, affecting a quarter of the adult population. It’s easily treated if you know you’ve got it; a reliable blood-pressure measuring device costing less than $5 would save many lives,” said Sir George Alleyne, director emeritus of the Pan American Health Organisation, in a statement issued by LMD.

Next: More business

LMD’s initial revenues will come from the sale of modules to Smartphone companies. Over the past two years, LMD has industrialised the module with several of the world’s largest assemblers and packagers of electronic technology to ensure it is in a position to go to high-production volumes.

Although almost one billion health sensors have been incorporated into smartphones in the past three years, none have been certified to medical accuracy by regulators (FDA, CE etc.), according to LMD. Nor have they been able to measure all five vital signs including blood pressure.

Other companies trying a similar approach include Valencell Inc. (Raleigh, NC) who are performing active signal processing to remove motion and exercise artifacts from the datastream acquired by the photodetector. In Sensifree’s case the principle of measurement is electromagnetic. An RF sensor is used to sense movement in the radial artery wall to track heart rate – and it is hoped blood pressure.

After the pulse is taken, digital signal processing is used to extract more information. Sensifree make the claim that RF consumes 10 percent of the power of an optical LED sensor, which in turn makes it more suitable for battery-operated fitness, well-being and medical applications.

LMD is funded by business angels, venture capital and “two major players in the smartphone sector,” according to the company’s website. Jones is also a director of another Lausanne company, Bright Sensors SA. Meanwhile LMD is also closing a Series C round of finance but Jones declined to name investors or say how much money the company has raised to date.

Jones is an experienced entrepreneur having founded one of the first companies to provide circuits in the form of IP cores under his own initials MEJ and which he eventually sold to Mentor Graphics in 1995. Between 2004 and 2011 Jones was CEO of Innovative Silicon SA in Lausanne, a company that worked on floating body memory technology.

Related articles:
Wearable medical devices: Blurring the lines
Hyperspectral smartphone demonstrated
RF sensor startup teams with Switzerland’s CSEM

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