CubiKG: DiY heart and activity tracking device

Maybe it was caused by work-related stress, or maybe by something else, but while writing my PhD thesis I felt that my heart started to act differently. In particular I felt odd, noticeable and unannounced poundings. Hoping that the problem would be temporary, I waited a couple of weeks for it to wear off, but it didn’t so a visit to the doctor was scheduled for further analysis. In the meanwhile, BITalino (http://www.bitalino.com) has become a staple in my stash of DiY hardware tools, and in the days preceding my medical appointment, I thought that doing some Electrocardiography (EKG) recordings of my pounding heart would at least be a memento of this period. Interestingly, even a medical layman like myself could see from the EKG that every now and then the heart sort of skipped a beat or was too eager to beat (these are called arrhythmias). On the day of my medical appointment, a standard EKG screening (with a couple of minutes worth of data) showed arrhythmias nowhere to be found. However, before the doctor sent me on my way, I thought that showing him the data I had collected wouldn’t hurt. After some quick fiddling with Python, the EKG strip shown in Figure 1 pops up to the doctor. Then after a more detailed examination - including an echocardiogram - the confirmation… I do have an arrhythmic heart, which turns out to be pretty common and nothing to worry about when the heart is structurally sound (as the echocardiogram confirmed in my case). Nevertheless, the doctor did recommend keeping an eye on whether the arrhythmias increase (which could mean trouble). Although I could keep slapping a bunch of cables and a PCB on me every day (Figure 2), miniaturized physiological computing devices are pretty fun to build and play with (at least for me) so I decided to make something more practical. The process resulted in CubiKG (https://opensource.com/life/15/6/how-build-diy-activity-tracking-device), a wearable Holter-like device that can be used at home or during sleep for Lead I EKG and activity tracking. CubiKG works with the open source Android app BITadroid for data logging (https://play.google.com/store/apps/details?id=ceu.marten.bitadroid&hl=en) and with freeware software like Kubios (http://www.kubios.com/hrv-standard/) for analysis.