Hiromichi Maki

A mobile phone-based Safety Support System for wandering elderly persons

A new safety support system has been developed to detect and transmit notification of a wandering elderly persons location. The system employs a low transmitting power mobile phone (PHS) and a personal computer (PC). The PHS is carried with the elderly person as a pendant. The PHS location is identified within 100m from the receiving antenna ID. Therefore, the system can detect whether the wandering elderly person is in or out of their home. When the wandering elderly person is away from home, the system automatically informs the caregiver via voice mode and sends the wandering elderly persons location map by e-mail.

A system for monitoring cardiac vibration, respiration, and body movement in bed using an infrared

We have developed a non-invasive system for monitoring cardiac vibrations, respiration and body movement of in-bed hospitalized patients and elderly people who need constant care. These physiological parameters are recorded by an infrared emitting diode and a photo transistor, which are attached between spring coils in bed mattress. The infrared emitting diode diffuses infrared light into the mattress. The diffusion of this energy is changed by mattress shape variations and spring coil vibrations, which modulate the intensity of the received infrared signal. The intensity is also modulated by physiological parameters such as heart pulse, respiration and body movement. The physiological parameters are detected from the received infrared intensity signal by low, high and band pass filters.

A remote monitor of bed patient cardiac vibration, respiration and movement

We have developed a remote system for monitoring heart rate, respiration rate and movement behavior of at-home elderly people who are living alone. The system consists of a 40 kHz ultrasonic transmitter and receiver, linear integrated circuits, a low-power 8-bit single chip microcomputer and an Internet server computer. The 40 kHz ultrasonic transmitter and receiver are installed into a bed mattress. The transmitted signal diffuses into the bed mattress, and the amplitude of the received ultrasonic wave is modulated by the shape of the mattress and parameters such as respiration, cardiac vibration and movement. The modulated ultrasonic signal is received and demodulated by an envelope detection circuit. Low, high and band pass filters separate the respiration, cardiac vibration and movement signals, which are fed into the microcontroller and digitized at a sampling rate of 50 Hz by 8-bit A/D converters. The digitized data are sent to the server computer as a serial signal. This computer stores the data and also creates a graphic chart of the latest hour. The person’s family or caregiver can download this chart via the Internet at any time.

A daily living activity remote monitoring system for solitary elderly people

A daily living activity remote monitoring system has been developed for supporting solitary elderly people. The monitoring system consists of a tri-axis accelerometer, six low-power active filters, a low-power 8-bit microcontroller (MC), a 1GB SD memory card (SDMC) and a 2.4 GHz low transmitting power mobile phone (PHS). The tri-axis accelerometer attached to the subjects chest can simultaneously measure dynamic and static acceleration forces produced by heart sound, respiration, posture and behavior. The heart rate, respiration rate, activity, posture and behavior are detected from the dynamic and static acceleration forces. These data are stored in the SD. The MC sends the data to the server computer every hour. The server computer stores the data and makes a graphic chart from the data. When the caregiver calls from his/her mobile phone to the server computer, the server computer sends the graphical chart via the PHS. The caregivers mobile phone displays the chart to the monitor graphically.

A new drip infusion solution monitoring system with a free-flow detection function

A new drip infusion solution monitoring system has been developed for hospital and care facility use. The system detects the fall of each drip chamber drop of fluid and also a free-flow situation. Three non-contacting copper foil electrodes are used. The electrodes are wrapped around the infusion supply polyvinyl chloride (PVC) tube from the solution bag, the drip chamber, and the infusion PVC tube from the drip chamber. Drip infusion fluids have electrical conductivity, so a capacitor is formed between the infusion fluid and each electrode. A thirty kHz sine wave is applied to the electrode wrapped around the infusion supply PVC tube from the solution bag. The capacity-coupled signal on the drip chamber electrode is the transducer output. When an infusion fluid drop is forming, its length and diameter, and therefore the drip chamber capacitance, are increasing, causing change in the output signal. The drip chamber electrode can detect the fall of each drip chamber drop of fluid. When the infusion solution becomes free-flow, an infusion fluid drop is not forming and the infusion fluid flows continuously. Therefore, the capacitance of the electrode around drip chamber does not change the output signal. On the other hand, the electrode wrapped around the infusion supply polyvinyl chloride tube under the drip chamber detects the thirty kHz sine wave conducted by the infusion fluid. The drip chamber electrodes and the infusion supply PVC tube under the drip chamber detect each drop of fluid and free-flow, respectively.

An ECG electrode-mounted heart rate, respiratory rhythm, posture and behavior recording system

R-R interval, respiration rhythm, posture and behavior recording system has been developed for monitoring a patients cardiovascular regulatory system in daily life. The recording system consists of three ECG chest electrodes, a variable gain instrumentation amplifier, a dual axis accelerometer, a low power 8-bit single-chip microcomputer and a 1024 KB EEPROM. The complete system is mounted on the chest electrodes. R-R interval and respiration rhythm are calculated by the R waves detected from the ECG. Posture and behavior such as walking and running are detected from the body movements recorded by the accelerometer. The detected data are stored by the EEPROM and, after recording, are downloaded to a desktop computer for analysis.

A new safety support system for wandering elderly persons

We have developed a new mobile phone-based safety support system for transmitting information of a wandering elderly persons location and the environmental sounds around that person. The system consists of a wearable sensor and a conventional desktop PC with Internet access acting as the server computer. The wearable sensor, which is attached behind the neck of the elderly persons shirt, is composed of a low transmitting power mobile phone (W-SIM), a small microphone and a one chip microcontroller. The wandering elderly persons location is identified within 100 m from the mobile phone companys antenna ID via the W-SIM. The caregiver sets the elderly persons movement area by specialized computer software. When the elderly person goes out of the area, the sensor automatically records the environmental sound around the wandering elderly person for the presumption of the persons situation with the small microphone. The W-SIM sends both the wandering elderly persons location and the environmental sound to the server computer. The server computer informs automatically the caregiver by the e-mail. The caregiver can monitor the sound and the map of the wandering persons location via Internet. The sound enables the presumption of an accurate location and the situation of the wandering elderly person.

A microcontroller-based implantable telemetry system for sympathetic nerve activity and ECG measurement

A passive implantable telemetry system employing a low power 8 bit microcontroller has been designed for chronic unanesthetized small animal studies. The implantable renal nerve activity and ECG system is powered by induction coupling. The gains of the neural signal (NS) and ECG amplifiers are microprocessor-controlled by on-off-keying of transmitted power modulated at 144 bps. Analog signals from the NS and ECG amplifiers are each converted to an 8-bit serial digital format. This is accomplished by two 8-bit A/D converters included in the single microcontroller. The converted binary code is applied to a passive RLC serial resonant circuit and transmitted by electromagnetic wave.

A wireless breathing-training support system for kinesitherapy

We have developed a new wireless breathing-training support system for kinesitherapy. The system consists of an optical sensor, an accelerometer, a microcontroller, a Bluetooth module and a laptop computer. The optical sensor, which is attached to the patient’s chest, measures chest circumference. The low frequency components of circumference are mainly generated by breathing. The optical sensor outputs the circumference as serial digital data. The accelerometer measures the dynamic acceleration force produced by exercise, such as walking. The microcontroller sequentially samples this force. The acceleration force and chest circumference are sent sequentially via Bluetooth to a physical therapist’s laptop computer, which receives and stores the data. The computer simultaneously displays these data so that the physical therapist can monitor the patient’s breathing and acceleration waveforms and give instructions to the patient in real time during exercise. Moreover, the system enables a quantitative training evaluation and calculation the volume of air inspired and expired by the lungs.

An implantable telemetry system powered by a capacitor having high capacitance

An implantable telemetry system, using a capacitor having high capacitance instead of the rechargeable batteries, has been designed for chronic unanaesthetized animal studies. This system can simultaneously record the cardiac sympathetic nerve activity and ECG. The power of the system is inductively coupled and transmitted to a 2.5 farad capacitor. The system, which is constructed by ultralow power analog and digital standard integrated circuits, has a transmission range up to 5 m, depending on intervening tissue depth and FM receiver characteristics. With the capacitor charging time of 5 minutes, the system can be driven for 120 minutes.