1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Light sensor

Discussion in 'Prius v Audio and Electronics' started by pdp, Mar 30, 2012.

  1. pdp

    pdp New Member

    Joined:
    Oct 26, 2011
    162
    16
    0
    Location:
    Bay Area, CA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    I always thought the Prius v did not have a light sensor since it does not have automatic headlights (I'm talking about the v3, not sure about the v5 or v5+ATP). But the other day I noticed that when I pulled into the garage, my GPS display dimmed. So it seems it does have a light sensor. Can anyone tell me if the light sensor is used for anything else except for dimming the screen?
     
  2. Keiichi

    Keiichi Active Member

    Joined:
    Feb 1, 2012
    808
    79
    2
    Location:
    Goleta
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    The v 5 Trim has Automatic Lights. I presume the base system would have dash light dimming though.
     
  3. pdp

    pdp New Member

    Joined:
    Oct 26, 2011
    162
    16
    0
    Location:
    Bay Area, CA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Yes, it does have dash light dimming, but like most other cars, it appears to be controlled by if the headlights or parking lights are on. However, sometimes the ambient light also affects the dimming of the navigation screen. It appear there are two sources of control for the dimming.

    A good way to sum up my question:

    What is controlled by the light sensor and what is controlled by turning on the headlights? Again this is a v3
     
  4. jdcollins5

    jdcollins5 Senior Member

    Joined:
    Aug 30, 2009
    5,131
    1,338
    0
    Location:
    Wilmington, NC
    Vehicle:
    2010 Prius
    Model:
    III
    I know the Climate Control system uses the light sensor in its Fuzzy Logic to determine climate control based on daylight or darkness. I know the light sensor controls the dash and Nav brightness when going in a tunnel during daylight, etc.

    I do not have Auto lights but know that this does control the lights if available.

    Not sure what else it is used for.
     
  5. ProximalSuns

    ProximalSuns Senior Member

    Joined:
    Mar 24, 2012
    1,877
    21
    27
    Location:
    PNW
    Vehicle:
    2012 Prius
    Model:
    Three
    I'm going into Toyota on Thursday to (hopefully) have them add the Auto/On/Off light switch which I'm sure uses the same light sensor. Which makes Toyota not putting on key safety feature like auto/on/off lights maddening. I post if they can do it and how much they want.
     
  6. swg

    swg 12 Prius / 13 Volt

    Joined:
    Feb 26, 2012
    78
    5
    0
    Location:
    Atlanta
    Vehicle:
    2012 Prius
    Model:
    Three
    They probably assume we can all see that it is getting dark and its time to turn on the lights. It will turn off the lights if you leave them on, even in the 3.
     
  7. ProximalSuns

    ProximalSuns Senior Member

    Joined:
    Mar 24, 2012
    1,877
    21
    27
    Location:
    PNW
    Vehicle:
    2012 Prius
    Model:
    Three
    They are called DAYTIME running lights for reason. Toyota making them manual disables a proven safety feature.

    DRL and auto/on/off lights should be standard equipment especially on a high tech car like Prius with digital displays that require ambient light adjustment and mask dawn/dusk need to turn lights on.

    You are defending the indefensible.
     
  8. Keiichi

    Keiichi Active Member

    Joined:
    Feb 1, 2012
    808
    79
    2
    Location:
    Goleta
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    Actually, the US version of the Prius v has no DRL, Auto or not.
     
  9. swg

    swg 12 Prius / 13 Volt

    Joined:
    Feb 26, 2012
    78
    5
    0
    Location:
    Atlanta
    Vehicle:
    2012 Prius
    Model:
    Three
    Oh, please let us know how much it is to have them change out the headlight switch and activate a non-existent DRL. Thanks.
     
  10. ProximalSuns

    ProximalSuns Senior Member

    Joined:
    Mar 24, 2012
    1,877
    21
    27
    Location:
    PNW
    Vehicle:
    2012 Prius
    Model:
    Three
    Which is crazy. That Toyota then essentially disables them by making them manual in many cases when supplied is equally crazy.

    Nearly all published reports indicate DRLs reduce multiple-vehicle daytime crashes. A study examining the effect of Norway's DRL law from 1980 to 1990 found a 10 percent decline in daytime multiple-vehicle crashes. A Danish study reported a 7 percent reduction in DRL-relevant crashes in the first 15 months after DRL use was required and a 37 percent decline in left-turn crashes. In a second study covering 2 years and 9 months of Denmark's law, there was a 6 percent reduction in daytime multiple-vehicle crashes and a 34 percent reduction in left-turn crashes.3 A 1994 Transport Canada study comparing 1990 model year vehicles with DRLs to 1989 vehicles without them found that DRLs reduced relevant daytime multiple-vehicle crashes by 11 percent.

    In the United States, a 1985 Institute study determined that commercial fleet passenger vehicles modified to operate with DRLs were involved in 7 percent fewer daytime multiple-vehicle crashes than similar vehicles without DRLs. A small-scale fleet study conducted in the 1960s found an 18 percent lower daytime multiple-vehicle crash rate for DRL-equipped vehicles. Multiple-vehicle daytime crashes account for about half of all police-reported crashes in the United States. A 2002 Institute study reported a 3 percent decline in daytime multiple-vehicle crash risk in nine US states concurrent with the introduction of DRLs.

    Federal researchers, using data collected nationwide from 1995-2001, concluded that there was a 5 percent decline in daytime, two-vehicle, opposite-direction crashes and a 12 percent decline in fatal crashes with pedestrians and bicyclists. However, a 2008 federal study concluded that DRLs have no significant effect on either of these crash types.
     
  11. anewhouse

    anewhouse Active Member

    Joined:
    Mar 26, 2012
    191
    105
    0
    Location:
    CNY
    Vehicle:
    2012 Prius v wagon
    Model:
    Three

    I'll be very curious to see how this turns out. In some cases, just changing the stalk switch allows new "features" that were not previously present on the car. In my previous car (Scion xD), there were no variable intermittent wipers. The options were very slow, slow, and high. After doing some forum reading, I bought a different wiper control stalk (actually from a Prius), which had the control ring to adjust the variable intermittent wipers. The size and wiring harness were identical, so it was a relatively easy to swap out the old stalk for the new one. Presto - variable intermittent wipers on my Scion, with no other wiring or mechanical changes.
    So I wouldn't be too surprised if replacing the stalk (with one that has an "auto" option on the switch) allows automatic headlight control on the v2/v3. I also wouldn't be too surprised if a headlight stalk from some other Toyota vehicle (Rav4? Tacoma? Prius? Camry?) is a direct replacement for the one in the v. I'd love to figure out if this is the case - auto headlights would be a great feature, and I'm also surprised that they're not included on a vehicle that's otherwise so full-featured.
    Andy
     
  12. ProximalSuns

    ProximalSuns Senior Member

    Joined:
    Mar 24, 2012
    1,877
    21
    27
    Location:
    PNW
    Vehicle:
    2012 Prius
    Model:
    Three
    I suspect that is the case since the light sensor is already talking to the computer and various devices are using that information already, nav and dash display.

    The stalk for Auto/On/Off likely requires plugging into existing ports and using existing information from the existing light sensor.

    Adding to the plot, Canadian Prius have to have automatic DRL's which are done with no real cost extra.
     
  13. pdp

    pdp New Member

    Joined:
    Oct 26, 2011
    162
    16
    0
    Location:
    Bay Area, CA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    This is exactly why I was wondering what else the light sensor controls in the Prius v... I never even knew the v 3 had one until one day I noticed the GPS display dimmed even without me turning on the headlights. Thanks, I'm going to look into this as well.
     
  14. pdp

    pdp New Member

    Joined:
    Oct 26, 2011
    162
    16
    0
    Location:
    Bay Area, CA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    I think I found the reason why it seems the light switch sometimes controls the dash dimmer and sometimes the light sensor controls the dash dimmer. Maybe it's been posted somewhere else before, but here are my observations. Again, this is a v3 which doesn't have auto headlights.

    The dash dimmer is ultimately controlled by the light switch; if the light switch isn't on (parking or full headlights), the dash will never dim. HOWEVER, the light sensor has the ability to override the dash dimmer when the light switch it on. So say I turn on my headlights when it is bright outside, the light sensor will not let the dash dim. But if I leave the headlights on and it slowly gets darker outside, the dash will dim on its own when it's dark enough. But the reverse will not happen: if it gets dark outside but the headlights are not on, the dash will never dim.

    This behavior is really cool IMO. I think someone mentioned in another thread that they leave their lights on 24/7 so they never forgot to turn it on. My complaint about that was the dash would also dim in broad daylight, because I assumed the dash would immediately dim when the lights are switch on. But with this discovery, that isn't a concern anymore.

    If anyone wants to confirm my observations, it would be nice to see if I missed anything.