Abstract: An electric whistle has a power circuit, an inductor, an electric switch, a buzzer, a tone-set resistor and a sound IC. The sound IC generates an audio control signal to activate the electric switch. When the electric switch is activated, the inductor produces an induction voltage to activate the buzzer. The oscillation frequency of the audio control signal is determined by the single tone-set resistor without a capacitor. Therefore, few passive devices are used. The electric whistle of the present invention is compact and portable.

Abstract: A vibration frequency adjusting system and method measures energy of a vibration generated by a vibrator of an electronic device, and converts the vibration energy to a level of electric charge. The system and method further compares the level of electric charge with preset electric charge thresholds, and adjusts the level of electric charge to a preset level of electric charge according to the comparison. Then, the system and method converts the adjusted preset level of electric charge to a voltage, and outputs the voltage to vibrator, so as to adjust the frequency of the vibration according to the voltage.

Abstract: A solar-powered wind chime has a solar energy system for powering an electrical subsystem. The electrical subsystem may include lighting elements for illuminating the wind chime and the area around the wind chime in a decorative and functional manner.

Abstract: An elimination-absorber monitoring system addresses diaper-monitoring problems with a unique, low cost, multi-layer disposable sensor structure that absorbs small volumes of urine, yet allows most urine volume to flow unimpeded through it, and into the diaper below. When connected with a reusable, miniature monitor/indicator unit, the sensor presents a clear and on-going change of measurement condition upon experiencing a rapid influx into the diaper of a significant volume of urine, and/or upon a significant reduction in the available absorbency of the diaper's top surface. The sensor additionally provides recessed, protected elements for similarly presenting a clear and on-going change in measurement condition upon experiencing the presence of fecal matter. Further provided is the monitor unit employing narrow, widely-spaced, fast rise-time, fast transition-time pulses for conductivity measurement and alarm activation.