Best place to mount photosensor?

sxtnitehawk · 03-10-2009, 10:59 PM

I want to have automatic headlights as a feature for my skin...where would be the best place to mount the photosensor so that it wont get bad readings from things like street lights, or oncoming traffic? dont want my headlights turning off at night because of a street light i'm passing....

corvettecrazy · 03-10-2009, 11:24 PM

Most OEM sensors are mounted on the flat piece where the defroster vent normally is. This is where I would mount one.

Since it sounds like you are integrating it, you should be able to say it has to be darker than X for X amount of time before they go on and lighter than X for X amount of time before they go off. That should eliminate the street light variable.

sxtnitehawk · 03-10-2009, 11:37 PM

cool, that's what i figured...

i knew i'de have to have a timer to determine when they should be on...

Chester · 03-11-2009, 12:01 AM

I think that you need a rolling average on the pickup from the photosensor anyway, as you want it to register a lack of outside lighting for a period of time (4-5 seconds?) before it triggers or kills the headlights.

That means you could mount the photosensor up behind the rear view mirror, which I think is where most of the new systems are done as well.

But you would need the average over a certain time to stop the unit from cycling on and off under streetlamps, bridges etc.

Edit: That will teach me for having the window open for an hour before answering!! Beaten!!

sxtnitehawk · 03-11-2009, 12:05 AM

yeah, i'm thinkin more like 10-15 seconds though...

it could take more than 4-5 seconds to pass a bright street lamp at night (for instance, state highways)

Chester · 03-11-2009, 07:57 AM

I have seen the Camry's over in Australia, their automatic headlights will turn on from driving under anything larger than a 2 lane bridge overhead, so I don't think they are set to turn on for anything more than 4-5 seconds, but maybe have the turn off average set to something a lot longer....end of the day its fine to have them come on when not really needed, but not turn off before its definately NOT needed.

Nomader · 03-11-2009, 08:05 AM

i would place the sensor inside the car under the steering wheel.. in a place that only gets ambient light..

sxtnitehawk · 03-11-2009, 08:43 AM

under the steering wheel wouldn't be a good idea, you wouldn't be able to get an accurate reading down there...once i get the carpc together and in the car, i'll test out different locations to see what's best... I'll most likely put it up on the dash, center, right at the base of the windsheild...

worst case scenario, if i cant get a good reading anywhere, i'll have the headlights just come on and stay on all the time when the computer is running......like my parents' subaru, lol