A study published in the journal Scientific Reports showed that researchers from the University of California, San Diego, have developed a simple, low-cost clip that uses a smartphones camera and flash to monitor blood pressure at the users fingertip.

The researchers revealed that to measure their blood pressure, the user simply presses on the clip with a fingertip. A custom smartphone app will guide the user on how hard and long to press during the measurement.

The clip is a 3D-printed plastic accessory that fits over the camera and flash of a smartphone. It has an optical design that is akin to a pinhole camera. When the user pushes the clip, the flash of the smartphone illuminates the users fingertip. That light is then projected to the camera as an image of a red circle through a pinhole-sized channel.

A spring within the clip allows the user to push with varying degrees of force. The larger the red circle on the camera, the harder the user presses. The red circle is used by the smartphone app to extract two key bits of information. The software can measure the amount of pressure applied by the users fingertip by looking at the size of the circle.

The app can also quantify the volume of blood flowing into and out of the fingertip by analysing the brightness of the circle. This data is converted into systolic and diastolic blood pressure measurements via an algorithm.

The footage was evaluated on 24 participants from the UC San Diego Medical Centre by the researchers. The findings were equivalent to those obtained using a blood pressure cuff. 

(Source:https://www.india.com/science/new-low-cost-clip-can-monitor-bp-using-your-smartphones-camera-6090411/ )