초록 ▼

A telltale for sensing and responding to ambient light levels. A photosensor monitors light levels and causes a bulb or other controlled element to be energized if ambient levels reach a threshold. In one embodiment a time delay is instituted between sensing the threshold light level and bulb energi

A telltale for sensing and responding to ambient light levels. A photosensor monitors light levels and causes a bulb or other controlled element to be energized if ambient levels reach a threshold. In one embodiment a time delay is instituted between sensing the threshold light level and bulb energization. This prevents false triggering on transitory conditions. An additional embodiment has a threshold level that uses hysteresis to avoid unstable sensing near the threshold level. A preferred use for the telltale is in apprising a motor vehicle operator when to turn on the vehicle headlamps.

대표청구항 ▼

Sensing apparatus for use in a motor vehicle comprising: energization means for providing an energization signal; sensor means for monitoring an ambient light level and producing a sensed signal related to said ambient light level; a timer coupled to the sensor means for generating an indicating out

Sensing apparatus for use in a motor vehicle comprising: energization means for providing an energization signal; sensor means for monitoring an ambient light level and producing a sensed signal related to said ambient light level; a timer coupled to the sensor means for generating an indicating output in response to a sensed signal corresponding to a threshold ambient light level; and a light source energized by the energization signal and coupled to the timer to respond to the indicating output if the ambient light level sensed by the sensor means reaches the threshold ambient light level; said timer responsive to said sensor means to energize said light source for a first time period and then de-energize said light source to allow the sensor means to sense ambient light levels without interference from the light output from the source.