Byung-Seop Song

Design of bi-directional and multi-channel miniaturized telemetry module for wireless endoscopy

A bi-directional and multi-channel wireless telemetry capsule, 11 mm in diameter, is presented that can transmit video images from inside the human body and receive a control signal from an external control unit. The proposed telemetry capsule includes transmitting and receiving antennas, a demodulator, decoder, four LEDs, and CMOS image sensor, along with their driving circuits. The receiver demodulates the received signal radiated from the external control unit. Next, the decoder receives the stream of control signals and interprets five of the binary digits as an address code. Thereafter, the remaining signal is interpreted as four bits of binary data. Consequently, the proposed telemetry module can demodulate external signals so as to control the behavior of the camera and four LEDs during the transmission of video images. The proposed telemetry capsule can simultaneously transmit a video signal and receive a control signal determining the behavior of the capsule itself. As a result, the total power consumption of the telemetry capsule can be reduced by turning off the camera power during dead time and separately controlling the LEDs for proper illumination of the intestine.

Implementation of a Transcutaneous Charger for Fully Implantable Middle Ear Hearing Device

A transcutaneous charger for the fully implantable middle ear hearing device (F-IMEHD), which can monitor the charging level of battery, has been designed and implemented. In order to recharge the battery of F-IMEHD, the electromagnetic coupling between primary coil at outer body and secondary coil at inner body has been used. Considering the implant condition of the F-IMEHD, the primary coil and the secondary coil have been designed. Using the resonance of LC tank circuit at each coil, transmission efficiency was increased. Since the primary and the secondary coil are magnetically coupled, the current variation of the primary coil is related with the impedance of internal resonant circuit. Using the principle mentioned above, the implanted module could transmit outward the information about charging state of battery or coupling between two coils by the changing internal impedance. As in the demonstrated results of experiment, the implemented charger has supplied the sufficient operating voltage for the implanted battery within about 10 mm distance. And also, it has been confirmed that the implanted module can transmit information outward by control of internal impedance

Microvibration transducer using silicon elastic body for an implantable middle ear hearing aid

Abstract In this paper, the microelectromagnetic vibration transducer is presented for the use of an implantable middle ear hearing aid, characterized by its small size, high efficiency and selective frequency bandwidth. In order to construct this, a new type of electromagnetic vibration transducer, composed of wound coil, a permanent magnet and a four-beam cross type silicon elastic body, is required. The fabricated transducer is useful for the application of 1–5 mA of a current source, 0.5–55 dyn of a vibration peak force and at a frequency range of a 100–7000 Hz.

Differential floating mass type vibration transducer for MEI system

A new of vibration transducer, a DFMT (differential floating mass type) is introduced for use in an MEI (middle ear implant) system. The DFMT transducer is not influenced by external noise magnetic flux and has a very high vibration efficiency because its two magnets, which are glued back to back with the same poles facing, are located in the coil.

Design of pillow type contactless recharging device for totally implantable middle ear systems

A contactless recharging device for totally implantable middle ear systems has been designed as a pillow type that the user can recharge the implanted battery with taking a rest. The proposed device uses the electromagnetic coupling between the transmitting coil and the receiving coil. To supply sufficient power for the implanted circuits, each coil uses LC resonance and the implanted device uses voltage doubler. A power MOSFET is used for switching the DC voltage of LC parallel circuit and the switching frequency demands on a programmable frequency generator which is controlled by microcontroller. In order to improve the electromagnetic coupling efficiency at specific positions of coil which may vary with the displacement of head, the optimal location of receiving coil was studied, and the 5 transmitting coils in a pillow for recharging the implant module was designed. From such a recharging experiment, it was found that the proposed device could provide the sufficient operating voltage within the distance of 4 cm between pillow and the implanted device.

Proposal of a piezoelectric floating mass transducer for implantable middle ear hearing devices

A new type of transducer, piezoelectric floating mass transducer (PFMT) which has advantages of piezoelectric and electromagnetic transducer has been proposed and implemented for the implantable middle ear hearing devices. By the uneven bonding of piezoelectric material to the inner bottom of transducer case, the PFMT can vibrate back-and-forth along the longitudinal axis of the transducer even though the piezoelectric material within the cylindrical case produces only the bilateral expansion and contraction according to the applied electrical signal. To improve efficiency of the PFMT, the multi-layered piezoelectric material has been adapted. The small number of components in the PFMT enables the simple manufacturing and the easy implanting into the middle ear. In order to examine the characteristics of vibration, mechanical modeling and finite element analyses of the proposed transducer have been performed. From the result of theoretical analyses and the measured data from the experiment, it is verified that the implemented PFMT can be used in implantable middle ear hearing devices.

Design and Implementation of a Controllable White Noise Generator for Tinnitus Therapy

The tinnitus which is the one of the auditory disease is a phenomenon that the patients feel the sound in the ear or the head when there is no sound sources. There have been many therapies for this tinnitus so far, but it is known that the TRT (Tinnitus Retraining Therapy) is the most effective therapy. So we designed and developed the controllable white noise generator for TRT. It must be designed as small as possible for user`s convenience, such as the ITE (In The Ear) type hearing aids. It used the thermal noise as the white noise source. And filter and tone control circuits are used at the end of the noise generation part to control the white noise characteristics. This link of the controllable circuits is used to change the white noise`s characteristic for the various tinnitus patients` characteristic. we can confirm that the designed and implemented controllable white noise generator which is a ITE type operates properly by the experiments of filter and tone control circuit.

Analysis and design of differential electromagnetic transducer for implantable middle ear using finite element method

A differential electromagnetic transducer (DET), which has similar frequency characteristics to those of the normal middle ear, has been designed and implemented for an implantable middle ear (IME). In order to optimize the DET characteristics that are practically determined by the electromagnetically forced vibration, a finite element analysis (FEA) simulation is carried out. The designed DET according to the simulation results is implemented using micro-machining technology. The vibrating displacement of the DET is about 200 nm in the range of 0.1 to 1.5 kHz when 1.5 mA/sub rms/ current is applied to the coil.

Implementation of miniaturized microphone unit for implantable hearing aid and its characteristics

In this paper the miniaturized microphone unit that can be utilized to the implantable middle car and inner ear is designed and implemented. The implantable microphone unit that planed to set up in the center of the pinna has been designed to ensure the necessary dynamic range and to improve the sensitivity of microphone unit. In addition to, the microphone unit is miniaturized and its biocompatibility of human body is considered. The microphone unit is composed of a minimized electric microphone, a titanium case which has 5.3 mm diameter and 3.7 mm height, a SUS316L vibrating membrane of 10 /spl mu/m thickness which is touched with a hypodermic tissue and adopted for the less attenuation of microphone sensitivity. Through the experiments of the fabricated microphone unit, it is verified that the implemented microphone unit operates up to the bandwidth of 5 kHz without declining of sensitivity in the 6 mm hypodermic tissue.

Implementation of Motorized Wheelchair using Speaker Independent Voice Recognition Chip and Wireless Microphone

For the disabled persons who can`t use their limbs, motorized wheelchair that is activated by voice recognition module employing speaker independent method, was implemented. The wireless voice transfer device was designed and employed for the user convenience. And the wheelchair was designed to operate using voice and keypad by selection of the user because they can manipulate it using keypad if necessary. The speaker independent method was used as the voice recognition module in order that anyone can manipulate the wheelchair in case of assistance. Using the implemented wheelchair, performance and motion of the system was examined and it has over than 97% of voice recognition rate and proper movements.