A wearable magnetic sensing device for identifying the presence of static magnetic fields

Nowadays, the ever growing use of electronic equipment in everyday life raises issues regarding the safety of specific population groups, such as patients carrying EMI sensitive implantable devices (e.g. cardiac pacemakers, surgical stents, etc.). In this respect, the need for wearable magnetic monitoring systems, able of detecting the presence of possibly hazardous magnetic fields of various different origins may become obvious. In this work, a wearable magnetic sensing device has been constructed in order to assess its ability to identify the presence of static magnetic fields of magnetic flux density up to 6 Gauss. Magnetostrictive delay lines (MDLs) have been employed as the sensing elements, due to their fibrous form and minimal thickness, which allows integration in textile and clothing products. Two different amorphous magnetostrictive materials, in ribbon and wire form respectively, have been tested in order to reveal the most appropriate solution for the application under consideration. Moreover, different performance aspects, such as uniformity of sensor's response as well as temperature effects have been examined. The experimental results indicate that the proposed system can effectively operate within the required magnetic flux density range. Moreover, the fibrous character of the MDL makes it a perfectly suitable material for wearable applications.