*Communication* **50/60 Hz Power Grid Noise as a Skin Contact Measure of Textile ECG Electrodes**

**Khorolsuren Tuvshinbayar <sup>1</sup> , Guido Ehrmann <sup>2</sup> and Andrea Ehrmann 1,\***


**Abstract:** The electrocardiogram (ECG) is one of the most commonly measured biosignals. In particular, textile electrodes allow for the measuring of long-term ECG without skin irritation or other discomforts for the patient. Such textile electrodes, however, usually suffer from insufficient or unreliable skin contact. Thus, developing textile electrodes is impeded by the often-complicated differentiation between signal artifacts due to moving and breathing and artifacts related to unreliable skin contact. Here, we suggest a simple method of using 50/60 Hz power grid noise to evaluate the skin contact of different textile electrodes in comparison with commercial glued electrodes. We use this method to show the drying of wetted skin under an embroidered electrode as well as sweating of the originally dry skin under a coated electrode with high water vapor resistance.

**Keywords:** electrocardiogram (ECG); Arduino; electrodes; conductive coating; conductive yarn; sensor
