Today, 40 secondary school students from the greater Dublin area learned to build their own ultra-low-cost heart rate monitors using the Arduino Nano. The signal we measured is called the photoplethysmogram (PPG). We detected small changes in blood vessel dilation caused by the variation in blood pressure occurring during each heartbeat.
Dr. Ted Burke was the main mastermind behind this particular design — the electronic circuit and the code to make it work. Dr. Damon Berry works on bio-medical applications like this, too, and today he explained that this PPG device is the same technology used in your smartwatch — except that this monitor is more precise (and also more delicate). A host of electrical and electronics lecturers and PhD researchers from TU Dublin helped deliver the workshop.
Ultimately, the students each built a monitor and learned how to manipulate the code to present data in different ways (e.g., the spike for a single heartbeat, versus a smooth curve line, or the raw read-out, which is a more spiked line affected by external interference).
I learned new things, too. Now I know how those stock market graphs are made where you can see a smoother line over time as opposed to the jumpy hour-to-hour or day-to-day line…. Thats’ what I call integration of learning right there! (Thanks, Ted! And, please correct me if I’m wrong on that.)
The students were happy to see the images from yesterday’s trip and asked if the tour leaders can gather more, so look for additions later this weekend. For now, I’m posting images of the morning’s monitor-building activity. Unfortunately, I had to step out to make a Teams call for a grant project right when things got most exciting — when everyone’s monitors started to pick up signals. Nevertheless, the process of building was also fun!
You see the first monitor to successfully and consistently record a heartbeat in the slides below. Congratulations to all the participants for a job well done!
I hope the pics below will help you see yourself as an engineer! We will be delighted to welcome you to TU Dublin if you choose a career in engineering!
Please see the page https://roboslam.wordpress.com/bioslam-ppg/ to see the build instructions.