My rear view mirror got knocked off windshield
02-01-2014, 08:23 PM
#16
Rennlist Member
No. There is a infrared LED shining shining at an angle on the glass providing the IR light and a sensor detecting how much IR light is reflected by the glass. Here's a diagram describing it:
And here is the whole article: http://www.gcoastautoglass.com/winds...s/rain-sensor/. It explains it better than I can.
And here is the whole article: http://www.gcoastautoglass.com/winds...s/rain-sensor/. It explains it better than I can.
02-03-2014, 04:32 PM
#17
Drifting
It works for similar reasons to why radio works when the sun emits a broad spectrum of electromagnetic waves as well. Tuning to a specific carrier frequency.
Solar IR, and IR from other external sources, will be broad spectrum, its energy content is spread across a wide range of frequencies. The IR emitter in the system pulses off and on at a very specific frequency. The receiver paired with it in the mirror is tuned to only pay attention to IR input at that frequency - filters out the rest. So it can easily detect a change in the reflection of only that light which originates inside the car sensor, vs the IR that comes form all the other sources.
Solar IR, and IR from other external sources, will be broad spectrum, its energy content is spread across a wide range of frequencies. The IR emitter in the system pulses off and on at a very specific frequency. The receiver paired with it in the mirror is tuned to only pay attention to IR input at that frequency - filters out the rest. So it can easily detect a change in the reflection of only that light which originates inside the car sensor, vs the IR that comes form all the other sources.
02-06-2014, 10:16 AM
#18
Drifting
As a kid I knocked the rear view mirror off my car. No internet or Google yet. I believe I tried super glue. Well the heat of the glue curing, cracked the windshield. $10 for the superglue. $1ooo for a new windshield. Ooops.
