My name is Piotr Lazarek. I’m a 19 year old engineer studying at Dulwich College in London. Because of the pandemic, I was forced to fly back to Poland for quarantine. To be frank, it wasn’t an easy time for me—after a week, I was practically dying of boredom. Thankfully, around that time, I received an invitation for a project called “COVID-19 Challenge”. The project was aimed at sixth form and university students who were passionate about science. We were supposed to work in groups of five people and find a solution for the following challenge: “How can we leverage technology—hardware and/or software—to mitigate the economic, social, or medical impacts of COVID-19?” We had exactly seven days to come up with an idea, create a product, and present our solution to the judges.
At the beginning, we discussed the most significant challenges posed by the disease and agreed to focus on finding an efficient way to track its spread. We did some research and found many mobile applications designed to do precisely what we were trying to achieve. Nevertheless, we didn’t give up and brainstormed ideas until someone mentioned the older generation. It was brilliant! We realized that the most endangered group in society was probably the least likely to benefit from these tracking applications, because they are less likely to use smartphones! This is how we came up with our solution—a small wearable device with a Bluetooth module on board, capable of tracking interactions with any other tracking devices or smartphones.
Since I was the only one on our team who was interested in engineering, I decided to design a printed circuit board on my own in Altium Designer®. At the beginning, I spent some time studying technical documentation of modules I intended to use in my device. Right after I chose every component, I started designing the schematic. The first step was to create the schematic library. This part was significantly simplified, thanks to the Altium Vault, which had symbols of nearly every element I needed. The rest was all about uploading these symbols from the library into the schematic and connecting them. This is the end result:
As you can see in the picture, the device is powered by a rechargeable Li-Ion coin cell battery and equipped with a Li-Ion battery charger module. The linear voltage regulator is being used to provide a 3.3V power supply to an STM32 microcontroller and a Bluetooth module. The microcontroller communicates with the Bluetooth module using a UART interface and multiple GPIOs. The data from the microcontroller can be synced with the database via either Bluetooth or micro USB connection.
The Layers Design
Right after I finished the schematic, I started working on the layers design. Firstly, I had to create a PCB library and design all the footprints I needed. Thanks to the footprint wizard available in Altium Designer, this task came down to just copying data from the datasheet. In the end, all I had to do was put everything together and create a 3D PCB model. Surprisingly I have learned something fundamental during the process. To be honest, I have never designed any devices capable of communicating wirelessly before. This is why I decided to read the Bluetooth module documentation carefully. It was a good thing I did, because otherwise, I would have made a terrible mistake! I realized that I couldn’t place any elements, ground planes, or even traces below the antenna, because they could effectively decrease its efficiency. With this essential information in mind, I have created the final design:
The Production Cost
When I was choosing which elements to use in my design, I had several criteria. First of all, I wanted to design a tiny device which could fit anywhere, so it had to be very small. Secondly, I was looking for modules with a low power consumption. And finally, they had to be as cheap as possible. I spent a couple of hours searching through practically every online store I could find, and I came up with only one conclusion: the device could be affordable, but only if we decided to mass-produce it. This is why we estimated the manufacturing cost of the device based on a production of 100,000 pieces (shown below).
To summarize, the older generation is the most vulnerable group in society to the global pandemic. According to the researchers, more than 60% of people aged 65 and older don’t use smartphones. To put that number into perspective, in London, there are roughly 650 thousand people aged 65+ who are unable to benefit from mobile applications meant to track the spread of COVID-19. During this week-long project, we designed a solution for this situation: a wearable tracking device capable of notifying its user of any potential interactions with ill people in the past.