Characterization and Fabrication of Low-Cost Flexible Tattoo Electrodes for Continuous Heart Rate Detection

Wearable electrodes are transforming health monitoring by enabling continuous, non-invasive tracking of physiological signals, offering significant benefits for personalized medicine and remote patient care. This study focuses on the design, fabrication, and evaluation of a flexible tattoo electrode for heart rate monitoring, printed using a desktop conductive printer, Voltera V-One. Characterization tests demonstrated that flexible conductive traces fabricated on PET substrates maintained stable resistance (with a maximum variation of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.6 \Omega$</tex>) under mechanical bending and temperature variations, ensuring signal reliability in wearable applications. The electrode uses biocompatible conductive material that resembles a tattoo. Using bench equipment and human trials, the performance of the electrode was tested. The experimental process focused on acquiring a signal that displayed the user's heart rate and then filtering it to produce a more refined signal with 39 dB SNR. The electrode successfully detected a heart signal. The produced outcome is a promising alternative for long-term ECG monitoring. The advancement of the electrode has the potential to improve wearable health monitoring and the care of remote patients.