Medical Devices

Perspective: How my injury helped me develop a tech solution

As part of an occasional series that aims to get personal insight into the changing technology industry, tech careers, and the effects of new technology on our lives, Lola Oyelayo, Director of Strategy & UX at Head London, explains how she worked with Head London to create a piece of wearable tech to aid her recovery from a ligament injury.

As a runner, tearing your anterior cruciate ligament (ACL) is a pain. Literally. I found this out for myself late last year when I fell over while training.

As a technology specialist, however, I was surprised at how little data healthcare professionals have to work with when this sort of injury occurs. In the months leading up to my operation I only saw my physiotherapist Jessica Harland twice a week. In the interim I was left wondering if I was doing the exercises correctly and if I was doing too much or not enough.

In fact, there was a complete lack of joint movement data. According to Jessica, the only data health professionals have is what they observe in checkups and what the patients say. And that’s when inspiration struck: a data-collecting brace would fill in the gaps between check-ups and help physios and consultants ensure patients are sticking to their exercise regimes. Plus it could show if the joint is recovering as expected.

My colleagues at Head helped design the wearable technology I needed. It had to sit on the side of a knee brace and analyse the angle of the knee flexion between 0 and 110 degrees. It had to keep track of flexion (the angle your knee joint opens to) and steps. These are two metrics that we could track with one sensor, a simple potentiometer.


We mounted the potentiometer over the pivot point of the knee on the brace to measure the knee bend. A Particle Photon microcontroller receives the input from the potentiometer, stores it on an SD card and sends data to the cloud via Wi-Fi. The technology also features a live Exercise Mode where the real-time flexion data is delivered via websockets to the web app, from which users can see their range of motion animated on screen in real time. 

The Photon is an inexpensive, tiny piece of kit with an onboard Wi-Fi antennae and cost $19. All the other components, in fact, didn’t exceed £20. Meanwhile, mobile phone charging batteries provided just over 24 hours of recording time.

The first challenge was to construct the potentiometer pivot arm, which was solved through both bespoke 3D-printed parts and, of all things, Meccano. Creating a suitable sensor mount meant combining an Allan key we cut down with a hacksaw and a Meccano beam to relay lower leg movement to the potentiometer. A lot of Velcro and some Sugru mouldable glue added a bit of weather-proofing.

The unobtrusive technology had to send real-time data to a dedicated API that converted the data into graphs. We researched health and fitness apps to get some ideas for tropes our web user interface could use and built the data visualisation system, while the hardware team limped around the office with laptops plugged into the prototype.

The API had its challenges too: we introduced an inactivity detection mechanism to increase the likelihood of data transmission when I wasn’t moving. But while the SD card was a roomy 8Gb, the internal memory of the Photon limited how much data could be sent to the API in one request and it had to be read off in chunks, affecting real-time performance.

Our compromise was that the inactivity detection delays sending the data to the API up to a point. Once it reaches a hard limit of around 10 minutes, the brace stops what it’s doing and performs a mass upload.

But importantly, these challenges could be overcome. We got it to work – and my physio is now able to log in and analyse real and accurate data on my knee from anywhere in the world. It also allows her to adapt and create bespoke recovery exercises and is being trialled by ten other patients besides myself. It’s a real example of the Internet of Things in action.

And what’s the best thing about this whole project? The connected brace (and I) now go by the moniker ‘RoboLola’ in the Head office. You can’t buy that sort of rep.


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