| 摘要 |
An untied shoelace warning system with a shoelace receiver and first and second sensors coupled to an indicator that activates when the system senses a shoelace segment, but senses it in an untied condition. The first and second sensors couple the indicator to a battery, and may all be contained within a housing. The first sensor is normally closed, but opens when a shoelace segment rests against it in a tied condition, and closes if the shoelace segment falls off the sensor, activating the indicator by coupling it to the battery. The second sensor is normally open, closing when it detects a shoelace segment. The system activates the indicator when a shoelace segment is not sensed by the first sensor, but is sensed by the second sensor. The system does not activate the indicator when a shoelace segment is not in the system, because neither the first nor the second sensor senses the shoelace. This way, the untied shoelace warning system does not activate the indicator when the shoe is not being worn. The indicator may be a sound device, e.g., a piezoelectric buzzer, a light or a series of lights, e.g., light emitting diodes or LED's, a vibrating device, or a combination of the aforementioned devices. |
