Implantable medical devices usually require a battery to operate and this can represent a severe restriction. In most cases, the implantable medical devices must be surgically replaced because of the dead batteries; therefore, the longevity of the whole implantable medical device is determined by the battery lifespan. For this reason, researchers have been studying energy harvesting techniques from the human body in order to obtain batteryless implantable medical devices. The human body is a rich source of energy and this energy can be harvested from body heat, breathing, arm motion, leg motion or the motion of other body parts produced during walking or any other activity. In particular, the main human-body energy sources are kinetic energy and thermal energy. This paper reviews the state-of-art in kinetic and thermoelectric energy harvesters for powering implantable medical devices. Kinetic energy harvesters are based on electromagnetic, electrostatic and piezoelectric conversion. The different energy harvesters are analyzed highlighting their sizes, energy or power they produce and their relative applications. As they must be implanted, energy harvesting devices must be limited in size, typically about 1 cm3. The available energy depends on human-body positions; therefore, some positions are more advantageous than others. For example, favorable positions for piezoelectric harvesters are hip, knee and ankle where forces are significant. The energy harvesters here reported produce a power between 6 nW and 7.2 mW; these values are comparable with the supply requirements of the most common implantable medical devices; this demonstrates that energy harvesting techniques is a valid solution to design batteryless implantable medical devices.

The growing demand for wearable devices is imposed by the ability to monitor in real-time critical situations in the different areas of daily life. In many cases, power is the limiting factor for such devices. One aspect is the power supply with batteries that introduces issues due to the weight, the overall dimensions, and the disposal of the batteries. A viable solution to overcome the limitations of batteries as power source is to harvest ambient energy to power the devices directly. In this paper, a proposed wearable device with an energy harvesting module has been designed, manufactured, and tested for the measurement of vital signs. The energy-harvesting module is implemented to directly power the electronic circuit board by a flexible solar panel. This paper describes the proposed instrumented autonomous T-shirt powered by the flexible solar panel applied directly on the T-shirt. The instrumented T-shirt is capable of measuring respiration rate, heart rate, and movement of the body. The methodology adopted, the design choices, and the experimental results are clearly reported and discussed. The experimental results show the functioning even with poor outdoor lighting conditions and under specific indoor constraints.\ud Tests have been conducted aiming to compare the instrumented T-shirt’s output data with the data obtained via instruments as gold standards and to show that the overall system described in this paper is capable of producing reliable data compared with\ud the data obtained with these instruments

The blind's capacities to navigate in a particular place and to organize their daily activities are of vital importance for their health and well-being. Organizing any kind of simple daily activity can be especially difficult; it is not easy for the blind to distinguish the different items, such as packaged foods and drug containers just by touching with their hands. RFID, or radio frequency identification, is a technology that can provide a support for improving the organization and orientation during the daylight activities. RFID uses radio waves to deliver data from a tag, which stores information, to a reader, which can elaborate the information making decisions. This technology is very useful in many different contexts such as scanning passports, shipments and automatic highway toll collecting. As the RFID technology stands out for its inherent technical nature of any basic RFID system, it may involve additional improvements for numerous applications in the field of health care. In this paper, a RFID device designed as a support for the blind in searching some objects is presented; in particular, it has been develop for searching the medicines in a cabinet at home. The device is able to provide to the blind some pieces of information about the distance and simplify the search; besides identifying the medicines, the device is able to provide the user an acoustic signal in order to find easily the desired product as soon as possible. It is noteworthy the fact that it gives the blind some items of information about the distance of a defined object, that is how near or far it is. This application is obtained using the RSSI (Received Strength Signal Indicator) value, measuring the power of the received signal of the tag